tag:theconversation.com,2011:/fr/topics/fiber-optics-22274/articlesFiber optics – The Conversation2024-02-27T14:08:45Ztag:theconversation.com,2011:article/2229052024-02-27T14:08:45Z2024-02-27T14:08:45ZAfrica needs China for its digital development – but at what price?<p>Digital technologies have many potential benefits for people in African countries. They can support the delivery of healthcare services, promote access to education and lifelong learning, and enhance financial inclusion. </p>
<p>But there are obstacles to realising these benefits. The backbone infrastructure needed to connect communities is missing in places. Technology and finance are lacking too. </p>
<p>In 2023, only <a href="https://www.itu.int/en/ITU-D/Statistics/Documents/facts/ITU_regional_global_Key_ICT_indicator_aggregates_Nov_2023.xlsx">83%</a> of the population of sub-Saharan Africa was covered by at least a 3G mobile network. In all other regions the coverage was more than 95%. In the same year, <a href="https://www.itu.int/en/ITU-D/Statistics/Documents/facts/ITU_regional_global_Key_ICT_indicator_aggregates_Nov_2023.xlsx">less than half of Africa’s population</a> had an active mobile broadband subscription, lagging behind Arab states (75%) and the Asia-Pacific region (88%). Therefore, Africans made up a substantial share of the estimated <a href="https://www.itu.int/en/mediacentre/Pages/PR-2023-09-12-universal-and-meaningful-connectivity-by-2030.aspx#:%7E:text=The%20number%20of%20people%20worldwide,global%20population%20unconnected%20in%202023.">2.6 billion</a> people globally who remained offline in 2023.</p>
<p>A <a href="https://gga.org/china-expands-its-digital-sovereignty-to-africa/">key partner</a> in Africa in unclogging this bottleneck is China. Several African countries depend on China as their main technology provider and sponsor of large digital infrastructural projects.</p>
<p>This relationship is the subject of a <a href="https://www.tandfonline.com/doi/full/10.1080/09692290.2023.2297363">study</a> I published recently. The study showed that at least 38 countries worked closely with Chinese companies to advance their domestic fibre-optic network and data centre infrastructure or their technological know-how. </p>
<p>China’s involvement was critical as African countries made great strides in digital development. Despite the persisting digital divide between Africa and other regions, 3G network coverage <a href="https://www.itu.int/en/ITU-D/Statistics/Documents/facts/ITU_regional_global_Key_ICT_indicator_aggregates_Nov_2023.xlsx">increased from 22% to 83%</a> between 2010 and 2023. Active mobile broadband subscriptions increased <a href="https://www.itu.int/en/ITU-D/Statistics/Documents/facts/ITU_regional_global_Key_ICT_indicator_aggregates_Nov_2023.xlsx">from less than 2% in 2010 to 48% in 2023</a>. </p>
<p>For governments, however, there is a risk that foreign-driven digital development will keep existing dependence structures in place.</p>
<h2>Reasons for dependence on foreign technology and finance</h2>
<p>The <a href="https://www.tandfonline.com/doi/full/10.1080/09692290.2023.2297363">global market</a> for information and communication technology (ICT) infrastructure is controlled by a handful of producers. For instance, the main suppliers of fibre-optic cables, a network component that enables high-speed internet, are China-based Huawei and ZTE and the Swedish company Ericsson. </p>
<p>Many African countries, with limited internal revenues, can’t afford these network components. Infrastructure investments depend on foreign finance, including concessional loans, commercial credits, or public-private partnerships. These may also <a href="https://www.sciencedirect.com/science/article/pii/S0308596124000107">influence a state’s choice of infrastructure provider</a>.</p>
<p>The African continent’s terrain adds to the technological and financial difficulties. Vast lands and challenging topographies make the roll-out of infrastructure very expensive. Private investors avoid sparsely populated areas because it doesn’t pay them to deliver a service there. </p>
<p>Landlocked states depend on the infrastructure and goodwill of coastal countries to connect to international fibre-optic landing stations.</p>
<h2>A full-package solution</h2>
<p>It is sometimes assumed that African leaders choose Chinese providers because they offer the cheapest technology. <a href="https://www.zdnet.com/home-and-office/networking/uganda-orders-probe-into-huaweis-fiber-project/">Anecdotal evidence suggests otherwise</a>. Chinese contractors are attractive partners because they can offer full-package solutions that include finance. </p>
<p>Under the so-called <a href="https://pdf.usaid.gov/pdf_docs/PA00TN5G.pdf">“EPC+F”</a> (Engineer, Procure, Construct + Fund/Finance) scheme, Chinese companies like Huawei and ZTE oversee the engineering, procurement and construction while Chinese banks provide state-backed finance. Angola, Uganda and Zambia are just some of the countries which seem to have benefited from this type of deal.</p>
<p>All-round solutions like this appeal to African countries. </p>
<h2>What is in it for China?</h2>
<p>As part of its <a href="https://link.springer.com/chapter/10.1007/978-1-137-57813-6_6">“go-global”</a> strategy, the Chinese government encourages Chinese companies to invest and operate overseas. The government offers financial backing and expects companies to raise the global competitiveness of Chinese products and the national economy. </p>
<p>In the long term, Beijing seeks to establish and promote Chinese digital standards and norms. Research partnerships and training opportunities expose a growing number of students to Chinese technology. The Chinese government’s expectation is that mobile applications and startups in Africa will increasingly reflect Beijing’s technological and ideological principles. That includes China’s interpretation of human rights, data privacy and freedom of speech. </p>
<p>This aligns with the vision of China’s “<a href="https://www.orfonline.org/research/the-digital-silk-road-in-the-indo-pacific-mapping-china-s-vision-for-global-tech-expansion">Digital Silk Road</a>”, which complements its <a href="https://www.cfr.org/backgrounder/chinas-massive-belt-and-road-initiative">Belt and Road Initiative</a>, creating new trade routes. </p>
<p>In the digital realm, the goal is technological primacy and greater autonomy from western suppliers. The government is striving for a more <a href="https://thediplomat.com/2021/04/chinas-digital-silk-road-and-the-global-digital-order/">Sino-centric global digital order</a>. Infrastructure investments and training partnerships in African countries offer a starting point. </p>
<h2>Long-term implications</h2>
<p>From a technological perspective, over-reliance on a single infrastructure supplier makes the client state more vulnerable. When a customer depends heavily on a particular supplier, it’s difficult and costly to switch to a different provider. African countries could become locked into the Chinese digital ecosystem.</p>
<p>Researchers like <a href="https://www.researchgate.net/profile/Arthur-Gwagwa">Arthur Gwagwa</a> from the Ethics Institute at Utrecht University (Netherlands) believe that China’s export of critical infrastructure components will <a href="https://www.dw.com/en/africa-embraces-huawei-technology-despite-security-concerns/a-60665700">enable military and industrial espionage</a>. These claims assert that Chinese-made equipment is designed in a way that could facilitate cyber attacks. </p>
<p>Human Rights Watch, an international NGO that conducts research and advocacy on human rights, has <a href="https://www.hrw.org/news/2023/05/09/future-technology-lessons-china-and-us">raised concerns</a> that Chinese infrastructure increases the risk of technology-enabled authoritarianism. In particular, Huawei has been <a href="https://www.wsj.com/articles/huawei-technicians-helped-african-governments-spy-on-political-opponents-11565793017">accused</a> of colluding with governments to spy on political opponents in Uganda and Zambia. Huawei has <a href="https://www.scmp.com/news/china/diplomacy/article/3023215/huawei-denies-helping-governments-uganda-and-zambia-spy">denied</a> the allegations. </p>
<h2>The way forward</h2>
<p>Chinese involvement provides a rapid path to digital progress for African nations. It also exposes African states to the risk of long-term dependence. The remedy is to diversify infrastructure supply, training opportunities and partnerships. </p>
<p>There is also a need to call for interoperability in international forums such as the <a href="https://www.itu.int/en/Pages/default.aspx">International Telecommunications Union</a>, a UN agency responsible for issues related to information and communication technologies. Interoperability allows a product or system to interact with other products and systems. It means clients can buy technological components from different providers and switch to other technological solutions. It favours market competition and higher quality solutions by preventing users from being locked in to one vendor. </p>
<p>Finally, in the long term African countries should produce their own infrastructure and become less dependent.</p><img src="https://counter.theconversation.com/content/222905/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephanie Arnold does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In sub-Saharan Africa, most governments welcome China’s investment in digital infrastructure.Stephanie Arnold, PhD Candidate, Università di BolognaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1443242020-09-02T12:24:00Z2020-09-02T12:24:00ZCOVID-19 lockdowns expose the digital have-nots in rural areas – here’s which policies can get them connected<figure><img src="https://images.theconversation.com/files/355879/original/file-20200901-22-vy5wj4.jpg?ixlib=rb-1.1.0&rect=1262%2C36%2C3575%2C2690&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">High-speed internet is harder to come by in the country.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-using-laptop-on-wooden-dock-in-field-royalty-free-image/88586463">Martin Barraud/Stone via Getty Images</a></span></figcaption></figure><p>The current public health emergency <a href="https://www.pewresearch.org/internet/2020/04/30/53-of-americans-say-the-internet-has-been-essential-during-the-covid-19-outbreak/">has shown just how critical</a> adequate and affordable broadband infrastructure is for communities and individuals trying to work, access health care and attempt to teach kids from home. </p>
<p>Yet <a href="https://docs.fcc.gov/public/attachments/FCC-20-50A1.pdf">over one-fifth of rural Americans lack access to broadband</a>, while some estimates suggest that figure could be <a href="https://broadbandnow.com/research/fcc-underestimates-unserved-by-50-percent">much higher</a>. </p>
<p>The problem has spurred many state governments to <a href="https://www.pewtrusts.org/en/research-and-analysis/data-visualizations/2019/state-broadband-policy-explorer">take an active role</a> in trying to connect more rural communities to high-speed internet, whether it’s by incentivizing providers to serve rural areas or creating dedicated offices aimed at helping more people get online. </p>
<p>As part of <a href="https://scholar.google.com/citations?user=UDypQAkAAAAJ&hl=en">our ongoing research</a> on how broadband access affects economic development, <a href="https://doi.org/10.1016/j.telpol.2020.102025">we conducted a study</a> that examined which of these state policies are actually working. </p>
<h2>Why broadband matters</h2>
<p>The pandemic has brought home the importance of high-speed internet access in all manner of everyday life. </p>
<p>Recent studies have found that broadband matters for <a href="https://www.doi.org/10.1007/s00168-014-0637-x">jobs, income</a>, <a href="https://doi.org/10.1093/ajae/aaw082">business relocation</a>, <a href="https://www.doi.org/10.1080/15575330.2016.1212910">civic engagement</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/31108509/">health</a>.</p>
<p>While availability has generally increased over the past decade, there is still a significant “<a href="https://www.pewresearch.org/fact-tank/2019/05/31/digital-gap-between-rural-and-nonrural-america-persists/">digital divide</a>” in terms of who has access to broadband. The latest data available shows that in some states, <a href="https://docs.fcc.gov/public/attachments/FCC-20-50A2.pdf">less than 50% of rural residents have a broadband connection available</a> where they live. </p>
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<h2>Policies meant to increase access</h2>
<p>Many state governments have adopted one or more of three approaches that can affect broadband availability: establishing broadband offices, increasing funding and restricting municipal networks. </p>
<p>In 2018, 25 states, including <a href="https://mn.gov/deed/programs-services/broadband/">Minnesota</a>, <a href="https://www.tn.gov/ecd/rural-development/tnecd-broadband-initiative.html">Tennessee</a> and <a href="https://www.ncbroadband.gov/">North Carolina</a>, had offices with full-time employees devoted to getting more residents connected to high-speed internet. In general, they <a href="https://ded.mo.gov/content/broadband-development">work with providers and communities</a> to find ways to connect those without high-speed connections and to improve adoption rates where broadband already exists. </p>
<p>A total of 18 states, such as <a href="https://cdola.colorado.gov/funding-programs/broadband-program">Colorado</a> and <a href="https://www.cpuc.ca.gov/General.aspx?id=8246">California</a>, had special funding programs that help subsidize broadband deployment in rural areas. These programs offer <a href="https://www.ny.gov/programs/broadband-all">financial incentives to providers</a> to install broadband infrastructure in lower-density areas where obtaining a profit is more difficult.</p>
<p><a href="https://www.newamerica.org/oti/reports/community-broadband/overcoming-state-laws-for-municipal-broadband-networks/">Utah</a>, <a href="https://docs.legis.wisconsin.gov/statutes/statutes/66/IV/0422">Wisconsin</a> and 18 other states have adopted <a href="https://muninetworks.org/content/preemption-detente-municipal-broadband-networks-face-barriers-19-states">policies that restrict the ability</a> of cities, utilities and other public entities to build their own broadband networks. Supporters of these restrictions, which aren’t intended to increase access, argue that <a href="https://www.telecompetitor.com/anti-municipal-broadband-legislation-progresses-at-state-level/">municipal networks represent unfair competition to private providers</a>. </p>
<p>We wanted to know how these policies affected the share of rural Americans connected to either standard broadband – with download speeds of at least 25 megabits per second – or a <a href="https://www.otelco.com/why-fiber/">fiber-optic network</a>. We also considered how the policies affected competition, defined as access to two or more providers. We <a href="https://www.pewtrusts.org/en/research-and-analysis/data-visualizations/2019/state-broadband-policy-explorer">analyzed data from 2012 to 2018</a> on all 3,143 U.S. counties and focused on the changes in <a href="https://www.census.gov/programs-surveys/geography/guidance/geo-areas/urban-rural.html">the rural portions of each county</a> since a policy was put in place. We performed a regression analysis to tease out the impact of each individual policy in states that implemented more than one. </p>
<p>We controlled for a variety of characteristics that might also affect broadband availability, such as population density, income and education. We also factored in political ideology, under the assumption that more conservative residents and legislatures are <a href="http://broadbandbreakfast.com/2020/05/partisan-disagreement-delays-broadband-funding-that-might-come-through-heroes-act/">less likely to support a broadband office or funding</a> and <a href="https://muninetworks.org/content/national-journal-traces-growth-partisanship-municipal-broadband-debate">more likely to impose municipal broadband restrictions</a>. </p>
<h2>Assessing the impact</h2>
<p>Overall, rural areas saw an average increase in broadband availability of 47 percentage points, rising from 24% in 2012 – around when many states began implementing policies – to 71% in 2018. Access to faster fiber climbed 16.5 points to 23%. </p>
<p>But these figures varied widely depending on which state a rural American lived in – and what policies were in place. </p>
<p>Having a dedicated funding program turned out to have the greatest positive impact on getting more people in rural areas connected to broadband and fiber. Our analysis found that the policy increased broadband access by an average of 1.8 percentage points compared with states without the policy in place. Gains for fiber were even higher at 2.1 percentage points. The share of counties with access to more than one broadband provider climbed 1.4 points above what would otherwise be expected. </p>
<p>Imposing restrictions on municipal broadband, on the other hand, had a significant dampening effect on internet access. Counties whose states imposed such restrictions experienced broadband access gains 3.7 percentage points less than what they would have enjoyed without the policies in place. Fiber access was 1.6 points less, while the policy had a negligible impact on competition. </p>
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<p>We found that state broadband offices had little impact on the availability of broadband or on the number of competitors, though they did lead to higher fiber availability, raising access by 1.5 percentage points more than in states without the policy. Recent research has emphasized the importance of the faster speeds that fiber provides <a href="https://doi.org/10.1016/j.telpol.2019.02.005">for economic growth and employment</a>.</p>
<p>But since broadband offices are relatively new, we believe the jury is still out on how effective they are. <a href="https://www.pewtrusts.org/-/media/assets/2020/03/broadband_report0320_final.pdf">Other research has found benefits to broadband offices</a>, such as better planning and outreach. It may just take more time for more of their benefits to show up in the data. </p>
<h2>Moving in the right direction</h2>
<p>Putting it all together, we would estimate that a state like Louisiana – with restrictions on municipal broadband and no dedicated funding program – could improve rural access to broadband by 5 percentage points above their normal rates of growth over the next six to seven years by changing those two policies. </p>
<p>And it seems like some states may already be aware of the advantages of doing so. In 2019, <a href="https://www.pewtrusts.org/en/research-and-analysis/articles/2020/04/23/progress-made-by-states-in-2019-is-key-to-increasing-broadband">seven more states put in place</a> funding programs to encourage broadband, and five softened their restrictions on municipal networks. Tennessee <a href="http://wapp.capitol.tn.gov/apps/BillInfo/Default.aspx?BillNumber=HB0819">is currently considering removing</a> its restrictions entirely. </p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p>
<p>On the whole, states have made significant gains in narrowing the rural-urban digital divide. Hopefully, states that have seen less improvement <a href="https://www.pewtrusts.org/en/research-and-analysis/reports/2020/02/how-states-are-expanding-broadband-access">will learn from their neighbors</a>. </p>
<p>But access is only part of the equation. Another <a href="https://www.digitalinclusion.org/blog/2019/05/30/fcc-broadband-report-ignores-affordability-issue/">important factor is affordability</a>, which is why it’s important for states to pursue policies that can increase competition and reduce prices, too.</p><img src="https://counter.theconversation.com/content/144324/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Whitacre receives funding from USDA Rural Utilities Service, USDA Economic Research Service, U.S. Department of Health and Human Services, Regional Rural Development Centers, Institute of Museum and Library Services, Health Research Services Administration, and the Oklahoma State Department of Health.</span></em></p><p class="fine-print"><em><span>Roberto Gallardo receives funding from USDA, EDA and several Indiana state agencies. </span></em></p>Americans depend more than ever on high-speed internet to connect to jobs, get health care and socialize. What policies really work to close the rural-urban digital divide?Brian Whitacre, Professor and Neustadt Chair in Agricultural Economics, Oklahoma State UniversityRoberto Gallardo, Director of the Purdue Center for Regional Development, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/966942018-06-12T19:59:58Z2018-06-12T19:59:58ZIn physics, a famous paradox that hangs by a thread of light…<figure><img src="https://images.theconversation.com/files/219379/original/file-20180517-155573-15imsa5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">file pwxht</span> </figcaption></figure><p>Imagine a metal bar that has been heated at one end. Instead of the heat gradually spreading over its entire length, the bar eventually becomes hot again at the place where it was originally. The fact that, paradoxically, a complex system returns to its original state instead of evolving toward equilibrium has drawn the attention of physicists for more than 60 years. Thanks to a series of advances in optical fibres, much richer and complete than before, our French-Italian team of researchers has just taken a crucial step in better understanding this phenomenon.</p>
<p><a href="https://www.researchgate.net/publication/324162686_Fibre_multi-wave_mixing_combs_reveal_the_broken_symmetry_of_Fermi-Pasta-Ulam_recurrence">Our publication</a>, which describes his progress, was featured on the cover of <em>Nature Photonics</em>. These are not only top results in fundamental physics but also of primary interest for the general public – the process in question is at the heart of phenomena such as the formation of rogue ocean waves or the design of high-precision optical clocks.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=744&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=744&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=744&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=934&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=934&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217226/original/file-20180502-153891-xotn7t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=934&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Enrico Fermi.</span>
<span class="attribution"><a class="source" href="https://fr.wikipedia.org/wiki/Enrico_Fermi#/media/File:Enrico_Fermi_1943-49.jpg">Department of Energy/Wikipedia</a></span>
</figcaption>
</figure>
<h2>The Manhattan project at the origin of the paradox</h2>
<p>The paradox was first discovered in 1954 by leading scientists, some of whom were involved in the <a href="https://www.britannica.com/event/Manhattan-Project">Manhattan Project</a>, which would provide the United States with the atomic bomb. They were <a href="https://en.wikipedia.org/wiki/Stanislaw_Ulam">Stanislaw Ulam</a>, <a href="https://en.wikipedia.org/wiki/John_Pasta">John Pasta</a>, and <a href="https://en.wikipedia.org/wiki/Mary_Tsingou">Mary Tsingou</a>, and <a href="https://en.wikipedia.org/wiki/Enrico_Fermi">Enrico Fermi</a>, winner of the 1938 Nobel Prize in physics. Fermi has the idea of using one of the first-ever computers to explore new complex physical phenomena whose resolution was not possible by calculation. This marks the beginning of a revolution – numerical simulations – that has become essential in all areas of physics.</p>
<p>But for Fermi and his colleagues, the results of the first computer test revealed some completely unexpected behaviour: The system they were studying returned to its initial state.</p>
<p>Since then, the problem has been studied and written about extensively. The repeated efforts of physicists to solve it have been particularly fruitful for many branches of physics where it can be observed. In particular, they led to the discovery of the theory of <a href="https://en.wikipedia.org/wiki/Soliton">solitons</a>, pulses that propagate without deformation that can be observed in oceans, plasma physics and optics.</p>
<p>Some models predicted that the Fermi, Pasta and Ulam phenomenon was actually cyclical – the system returning several times to its initial state. But the experiments that had highlighted it had never detected anything more than a return to the original state: intrinsic losses of the system mitigated its manifestations too quickly.</p>
<h2>Optical fibres observe the paradox</h2>
<p>Our research team, based at the University of Lille’s <a href="http://www.phlam.univ-lille1.fr/">PHLAM Laboratory</a> and associated with an Italian theorist from the University of Ferrara, has managed to find a way to compensate these losses over more than 8 kilometres of optical fibre by adding a light source of a very different colour that served as an energy reservoir. This unprecedented process allowed us to observe for the first time a second return to the initial state. The experiment took place at the <a href="http://fibertech.univ-lille.fr/presentation">FiberTech Lille</a> facility, part of the <a href="http://www.ircica.univ-lille1.fr/">IRCICA</a> research institution.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217185/original/file-20180502-153914-1q248c6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Light scattering in an optical fibre.</span>
</figcaption>
</figure>
<p>Thanks to an ingenious device that looked at diffusion of light by impurities within the fibre, known as <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html">Rayleigh scattering</a>, we were able to measure not only the intensity of the light but also what the optical specialists call its phase, and this along the whole fibre length. We then observed an unprecedented behaviour: recurrent shifts from one cycle to another, the maxima taking the place of the minima.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=607&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=607&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=607&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=762&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=762&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217259/original/file-20180502-153888-lgno7r.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=762&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Several Fermi-Pasta-Ulam recurrences, with alternating maxima (red) and minima (light blue).</span>
</figcaption>
</figure>
<p>This result, predicted by some models, opens a new way in the understanding of this phenomenon, which at the root of many other complex processes: <a href="https://en.wikipedia.org/wiki/Frequency_comb">frequency combs</a>. These “laser rules”, advancing swiftly in recent years, bring light into a large number of new applications, ranging from distance measurement for autonomous cars to the discovery of exoplanets, to name just a few.</p><img src="https://counter.theconversation.com/content/96694/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnaud Mussot has received funding from the Agence Nationale de la Recherche (ANR), the Labex Centre Europeen pour les Mathematiques, la Physique et leurs Interactions (CEMPI), the FLUX team and the Hauts-de-France region. He is a member of the Institut Universitaire de France.</span></em></p><p class="fine-print"><em><span>Matteo Conforti has received funding from Agence Nationale de la Recherche (ANR) under projects NoAWE and CEMPI, and the Hauts-de-France region.
</span></em></p><p class="fine-print"><em><span>Stefano Trillo receives funding from Italian Ministry of University and Research (MIUR) under PRIN action, and from University of Ferrara under FAR action.</span></em></p>In 1954, three scientists observed a paradox to which they gave their name: the Fermi-Pasta-Ulam recurrence. Now, fibre optics are on the way to finally providing an explanation.Arnaud Mussot, Professeur au Laboratoire de Physique des Lasers Atomes et Molécules (PHLAM), CNRS UMR8523, IRCICA, Université de LilleMatteo Conforti, Chercheur au Laboratoire de Physique des Lasers, Atomes et Molécules, Université de LilleStefano Trillo, Professor of Optics, University of FerraraLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/860752017-10-25T19:52:25Z2017-10-25T19:52:25ZAnd suddenly, the dam broke, letting the grains of light gush forth…<figure><img src="https://images.theconversation.com/files/191178/original/file-20171020-22945-1ie7o54.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Example of nonlinear effect which can be observed in an optical fiber. All the colors of the rainbow are generated at the output while only one color is present at the entrance. We're talking about supercontinuum.</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Physicists from the University of Lille, in collaboration with the University of Ferrara in Italy, have introduced a river into an optical laboratory… They have just observed the rupture of a photon barrier in an optical fibre, a phenomenon directly comparable with the rupture of a dam placed on the bed of a river.</p>
<p>We and our colleagues have taken advantage of the analogy between the propagation of waves in rivers and the propagation of light pulses in optical fibres to study in detail the formation of the unfurling wave that immediately follows the break of a dam on a river. And this, comfortably installed in our optical laboratory without risk.</p>
<h2>Drops of water in an optical fibre?</h2>
<p>It is more than an analogy: under certain conditions, the equations governing the propagation of these waves are strictly identical for each of these media. It is thus surprising that the behaviour of these two physical systems, <em>a priori</em> completely different, is identical. More precisely, we have shown that the tiny drops of water trapped behind the dam behave like grains of light – the photons – of a laser beam when they propagate in an optical fibre. We point out that this analogy had been used more than ten years ago to study the <a href="https://www.nature.com/nature/journal/v450/n7172/full/nature06402.html">formation of rogue waves</a>.</p>
<p>The situation we have studied is completely different. It is a dam placed on the bed of a river that breaks suddenly (nothing to do with a rogue wave). In order to mimic the rupture of a dam in an optical fibre, French and Italian physicists injected into a fibre a laser beam whose variations in intensity versus time corresponds to the difference in water levels located upstream and downstream of the dam.</p>
<p>To do this, the laser is forced to emit a burst of light in the form of a stair step, the level of the steps corresponding to the luminosity of the laser. A first step, of very low intensity followed by a second of very strong luminous intensity. The levels of light intensity are then similar to the levels of water in the river. It is important to emphasize that in order for the correspondence to be valid it is essential that the transition be extremely rapid between these two steps : usually 20 picoseconds or 20 billionths of a millisecond, which makes these experiments very tricky both for the generation of the signals as for their characterization. High-performance devices are needed to achieve this level of accuracy.</p>
<h2>Staircase pulses</h2>
<p>During its propagation in the optical fibre, the temporal appearance of the laser pulse, initially in the step of the staircase, is modified because, on the one hand, new colours are generated and, on the other hand, these colours do not travel at the same speed. The sudden transition between these two steps gradually and inextricably evolves towards a smoother transition. The dam is broken! The unfurling wave leads by the generation of a shock wave and rarefaction wave that connect the two stairs.</p>
<p>These two waves provide the transition between the two levels of intensity in the laser frame, or both levels of water in a dam on a river. Let us emphasize, it is important, that the set of experimental observations has been validated by numerical simulations. This confirms that the model used precisely describes the phenomenon and therefore reinforces the strength of the analogy.</p>
<p>The main difference lies in the fact that in optics, evolution takes place along the fibre length, whereas in the case of a river, the evolution parameter is the time. Thus, to follow the formation of the wave following the breaking of a dam, it is necessary to record the temporal shape of the laser for different fibre lengths, as shown in the figure below.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191167/original/file-20171020-28451-gn43tz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Breaking of a dam based on numerical simulations on a river/in an optical fibre.</span>
<span class="attribution"><span class="source">Author</span></span>
</figcaption>
</figure>
<p>Unlike breaking a dam on a river, the experiment performed in an optical laboratory is risk-free, repeatable and the set of parameters finely adjusted. It is indeed very easy to change the power of the laser, its colour or the type of optical fibre. Thus, it is possible to scan a wide range of parameters to achieve a fine understanding of the phenomenon (we used the <a href="http://fibretech.univ-lille.fr/presentation"><em>FibreTech Lille</em></a> drawing tower of the PHLAM laboratory, based in <a href="http://www.ircica.univ-lille1.fr/">IRCICA</a> to develop and manufacture optical fibres optimized for this experiment).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191166/original/file-20171020-28445-ebd8zi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Equipment of the <em>Fibretech Lille</em> fibre-optic drawing tower.</span>
<span class="attribution"><span class="source">Author</span></span>
</figcaption>
</figure>
<h2>Scientific approach and perspectives</h2>
<p>Because of the formal analogy between these two domains, all the conclusions and interpretations can be transposed to the case of the breaking of a dam on a river. This work constitutes the first experimental validation of predictions based on a celebrated theory developed by the mathematician <a href="https://en.wikipedia.org/wiki/Gerald_B._Whitham">G.B. Whitham</a> several decades ago and the experimental system implemented will allow us to study a more general problem posed by the famous mathematician <a href="https://en.wikipedia.org/wiki/Bernhard_Riemann">Riemann</a> in the nineteenth century.</p>
<p>Finally, this work illustrates the approach that physicists follow in everyday life. They develop the most universal models possible to describe and predict what is observed in nature, by collaborating with experts from different countries. </p>
<hr>
<p><em>This article is based on paper published in the journal Physical Review Letters, <a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.254101">“Dispersive Dam-Break Flow of a Photon Fluid”</a>.</em></p><img src="https://counter.theconversation.com/content/86075/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnaud Mussot is a member of the Iinstitut universitaire de France.</span></em></p><p class="fine-print"><em><span>Matteo Conforti has received support from the Agence nationale de la recherche.</span></em></p><p class="fine-print"><em><span>Stefano Trillo has received funding from italian Ministry of Research</span></em></p>To understand what is happening in an optical fibre, physicists can mimic a rupture of the flow of grains of light – the photons – thanks to a laser device.Arnaud Mussot, Professeur au Laboratoire de Physique des Lasers Atomes et Molécules (PHLAM), CNRS UMR8523, IRCICA, Université de LilleMatteo Conforti, Chercheur au Laboratoire de Physique des Lasers, Atomes et Molécules, Université de Lille - initiative d'excellenceStefano Trillo, Professor of Optics, University of FerraraLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/716762017-03-06T02:14:44Z2017-03-06T02:14:44ZAmerica’s broadband market needs more competition<figure><img src="https://images.theconversation.com/files/158608/original/image-20170227-26326-15wvoq5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How many people are trying to connect America's cities?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/technicians-connecting-network-cable-connection-concept-88451932">Network workers via shutterstock.com</a></span></figcaption></figure><p>The United States is home to some of the most creative people and businesses on the planet. Our filmmakers, artists, software engineers and scientists entertain the world and expand the boundaries of human knowledge. Their creative process is often a mystery, but their tools are not. Among these tools, few are more critical than the internet, which fosters creativity and innovation by facilitating access to information and supporting collaborative work. It is the enzyme that accelerates the creative economy, much like waterways, railroads and roads fueled the industrial era.</p>
<p>But there is a catch: Our world-class creators live in communities where internet access services are far from world-class. Take the example of Los Angeles, a major creativity hub: Using data from the California Public Utilities Commission, <a href="http://usc-annenberg.maps.arcgis.com/apps/webappviewer/index.html?id=8f4cee8ba8fa478396e947cb595674f3">we mapped</a> the availability of different home internet services across Los Angeles County. We then combined the results with demographic data, which allowed us to analyze the interplay between internet infrastructure and community demographics in close geographical detail.</p>
<p>Our results show that <a href="http://arnicusc.org/publications/c2ig-policy-brief-1/">nearly two-thirds of Angelenos live in areas served by just one internet provider</a> that offers speeds meeting the Federal Communications Commission’s current definition of “broadband” service – <a href="https://www.fcc.gov/reports-research/reports/broadband-progress-reports/2016-broadband-progress-report">25 Mbps download and 3 Mbps upload</a>. Competition is slightly stronger in the wealthier areas of the county, along the coast and in the San Fernando Valley.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=848&fit=crop&dpr=1 600w, https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=848&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=848&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1065&fit=crop&dpr=1 754w, https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1065&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/158609/original/image-20170227-26298-1x7hu6u.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1065&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Only one-third of Los Angeles County residents have more than one option for internet service that meets the FCC’s broadband standard.</span>
<span class="attribution"><span class="source">Hernán Galperin</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Weak competition yields high prices for consumers and little pressure for companies to upgrade their networks to offer better service. For example, in LA County, fiber-based services (capable of delivering speeds far faster than legacy technologies like cable or DSL) are available in less than a quarter of census blocks. By comparison, fiber coverage in cities like Stockholm and Paris (where residents have a choice of at least <a href="https://www.publicintegrity.org/2015/04/01/16998/us-internet-users-pay-more-and-have-fewer-choices-europeans">six providers</a>) is approaching <a href="https://observatoire.francethd.fr/">100 percent</a>. Further, the speeds offered in monopoly areas are 35 percent lower than those offered in areas with three or more competitors. This suggests that increasing competition in America’s broadband market would offer a better on-ramp to the creative lifeline of the internet.</p>
<h2>Little head-to-head competition</h2>
<p>The situation in LA County reflects two major trends in U.S. broadband markets:</p>
<p>1) The ongoing <a href="http://www.npr.org/sections/thetwo-way/2016/10/22/498996253/timeline-at-ts-merger-with-time-warner-follows-decades-of-industry-deals">industry consolidation</a> in the telecom and cable TV markets;</p>
<p>2) <a href="https://www.publicintegrity.org/2015/04/01/16933/how-broadband-providers-seem-avoid-competition">Weak competition</a> between DSL (which uses existing landline telephone wires to deliver broadband) and cable-internet services.</p>
<p>One of our key findings is that there is almost no geographical overlap between competitors with the same technology. Of the more than 73,000 census blocks in LA County – the smallest unit of geography government data can be broken into – only about 2,500 (3 percent) are served by more than one DSL provider. Likewise, only 850 blocks (about 1 percent) are served by more than one cable-internet provider. Alas, most households have to choose between one cable provider and one DSL provider; often, one of them fails to meet the FCC’s broadband speed threshold.</p>
<p>Competition has reached such lows that recent mergers aren’t making much difference. Take, for example, Charter Communications’ acquisition of Time Warner Cable in May 2016, a mega-merger of cable rivals that was <a href="http://www.latimes.com/business/lazarus/la-fi-lazarus-spectrum-cable-bills-20161004-snap-story.html">expected</a> to reduce competition and increase prices throughout LA County. But fewer than 1 percent of Angelenos lived in areas previously served by both operators. The merger couldn’t reduce competition because there was so little tto begin with, as companies divvy up territory to avoid competition.</p>
<p>The most recent <a href="https://www.fcc.gov/reports-research/reports/broadband-progress-reports/2016-broadband-progress-report">FCC Broadband Report</a> finds that the situation in Los Angeles is typical of other large metro areas. And it is worse in rural America, where 40 percent of residents lack access to broadband services.</p>
<h2>Communities stand up for themselves</h2>
<p>A key barrier to more competition is the expense of installing wired networks across large areas. In the past, federal policies required the few companies with existing networks to allow competing providers to serve customers over those same wires. But <a href="http://scrawford.net/wp-content/uploads/2011/08/The-communications-crisis-in-America-final.pdf">those days are gone</a>, largely because the incumbent cable and phone companies successfully fought them in court.</p>
<p>As a result, many local governments have <a href="https://theconversation.com/municipal-broadband-offers-hope-for-lagging-us-internet-36473">taken matters into their own hands</a>. In 2014, LA Mayor Eric Garcetti launched <a href="http://citylinkla.org/">CityLinkLA</a> seeking to secure private investments in high-speed internet networks that would provide every resident with a basic level of internet service for free, or at very low cost. The system Garcetti envisioned would also be able to offer much faster speeds than today’s commercial service – 1 Gbps or more – at competitive rates.</p>
<p>So far, however, CityLinkLA has not attracted large investments in new broadband infrastructure, particularly for gigabit-speed services. Moreover, our analysis shows that fiber-optic investments have been concentrated in wealthier communities, exacerbating the <a href="http://www.pewinternet.org/2015/12/21/home-broadband-2015/">growing divide</a> between those with lightning-speed home connections and a digital underclass forced to rely on their smartphones and mobile data plans.</p>
<p>Geography and demographics present numerous challenges to the roll-out of advanced network infrastructure in many U.S. cities, including Los Angeles. However, an <a href="https://www.publicintegrity.org/2015/04/01/16998/us-internet-users-pay-more-and-have-fewer-choices-europeans">analysis</a> by the Center for Public Integrity shows that, when comparing US and French cities with similar population densities (such as Nice and Columbus, OH), Americans paid more and had less choice in broadband. If our people and businesses are to continue thriving in a knowledge-based economy, and if we seek to build new opportunities for struggling communities, we must do better. </p>
<p>Help is unlikely to come from Washington, where the newly appointed FCC chairman has <a href="https://arstechnica.com/tech-policy/2017/02/fcc-makes-it-harder-for-poor-people-to-get-subsidized-broadband/">consistently voted</a> against federal subsidies for broadband expansion projects. Rather, we should look at the example of communities across America, large and small, that are building upon existing city assets to accelerate the equitable deployment of next-generation internet infrastructure. For example, the city of Los Angeles already owns over 800 miles of fiber optic cable, and there is <a href="http://citylinkla.org/rfp/RFP-CityLinkLA-6-16-15-c2.pdf">significant spare capacity</a>. This and other locally owned assets can be leveraged to offer Angelenos, and Americans, the world-class internet service they deserve.</p><img src="https://counter.theconversation.com/content/71676/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>World-class fiber-based internet service is available in less than a quarter of Los Angeles County. By contrast, it’s almost ubiquitous in Stockholm and Paris.Hernán Galperin, Research Associate Professor of Communication, USC Annenberg School for Communication and JournalismAnnette M. Kim, Associate Professor of Public Policy, University of Southern CaliforniaFrançois Bar, Professor of Communication and Spatial Sciences, USC Annenberg School for Communication and JournalismLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/573402016-04-07T20:05:44Z2016-04-07T20:05:44ZTwisted light could dramatically boost internet speeds<figure><img src="https://images.theconversation.com/files/117780/original/image-20160407-13983-3puq0t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A new development could mean vastly increase data transfer over optical fibre cables.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><a href="http://www.explainthatstuff.com/fiberoptics.html">Fibre optics</a> allow for the communication of data at the speed of light.</p>
<p>But the amount of data that can be sent along any optic fibre is limited by how much information you can encode into the light wave travelling through it.</p>
<p>Currently, optic fibre technology uses several different properties of light to encode information, including brightness, colour, polarisation and direction of propagation. </p>
<p>But if we want to cram even more information through optic fibre, we need to use other features of light to encode more information, without disrupting currently used properties.</p>
<p>Such a feature could help boost the bandwidth of optic fibre technology, including our internet speeds. </p>
<h2>Detecting the twist</h2>
<p>If the light wave travelling through the optic fibre is twisted helically – like a spring – then it has angular momentum, which is a measure of its momentum when it rotates around a point.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/iWSu6U0Ujs8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A quick primer on angular momentum.</span></figcaption>
</figure>
<p>But there was a major problem with using angular momentum to decode the information from the optic fibre. We needed a material with tiny nanoscale helical structures that could detect the twisted light.</p>
<p>Our research, published today in <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aaf1112">Science</a>, shows how we can control the angular momentum of light at a nanoscale using an integrated photonic chip.</p>
<p>So for the first time, we have a chip with a series of elaborate nano-apertures and nano-grooves that allow for the on-chip manipulation of twisted light.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117765/original/image-20160407-13987-1junztc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The nanophotonic chip magnified 2,000 times. Each indentation on the image is a single unit of the chip, like a single pixel in a display panel, made up of semi-circle nano-grooves and nano-apertures engraved in a metallic film.</span>
<span class="attribution"><span class="source">RMIT University</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The helical design of these tiny apertures and grooves removes the need for any other bulky interference-based optics to detect the angular momentum signals.</p>
<p>So if you send an optical data signal to a photonic chip, which is a microchip that uses light instead of electrons, then it is important to know where the data is going, otherwise information will be lost.</p>
<p>Using our nanophotonic chip, we can precisely guide angular momentum data signals without losing the information they carry.</p>
<p>What’s more, the angular momentum information of many different signals can be processed at the same time through the chip.</p>
<p>This means we can potentially achieve an ultra-wide bandwidth, with six-orders magnitude of increased data access compared to current technology.</p>
<h2>Technology for today</h2>
<p>Owing to the rapid development of nano-fabrication technology, we believe there is no technical challenge to the mass production of this chip today.</p>
<p>This breakthrough opens an entirely new perspective in employing light for chip-scale information generation, transmission and retrieval of images, videos, sounds and so on.</p>
<p>It could be used in applications such as data transmission, ultra-high definition displays, ultra-high capacity optical communications and ultra-secure optical encryption.</p>
<p>For example, the communication speed on the National Broadband Network can be boosted through the parallel processing of the angular momentum.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/117766/original/image-20160407-13952-vj8k6t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Professor Min Gu with the nanophotonic chip that can harness the angular momentum of light.</span>
<span class="attribution"><span class="source">RMIT University</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Since the chip consists of an array of individually-controlled single units, and each single unit is capable of independently processing the angular momentum information, this chip device allows for parallel processing of optical information.</p>
<p>A large number of optical fibres in one fibre bundle can be processed through the chip in parallel, which means the processing speed can be significantly increased by considering how large the array is.</p>
<p>For example, if we take 100 by 100 of such units in the array for the chip, then the speed could be boosted by four orders of magnitude.</p>
<p>This quirk of physics could one day lead to significantly faster internet speeds along with a host of other useful applications.</p><img src="https://counter.theconversation.com/content/57340/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Min Gu receives funding from the Australian Research Council Laureate Fellowship program (FL100100099) and from the Australian Research Council Centre of Excellence for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS) (project number CE110001018).</span></em></p><p class="fine-print"><em><span>Haoran Ren and Qiming Zhang do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The design of a new chip to detect the twisted nature of light waves could pave the way for next generation of optical communication technologies.Min Gu, Associate Deputy Vice-Chancellor for Research Innovation and Entrepreneurship, RMIT UniversityHaoran Ren, PhD candidate, Swinburne University of TechnologyQiming Zhang, Senior Research Fellow, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/509412015-11-30T05:50:55Z2015-11-30T05:50:55ZA full fibre network is the only way to future-proof Britain’s digital economy<p>Another day, another government announcement heralding the coming of high-speed broadband for all – in this case the call, by the prime minister, David Cameron, call to <a href="http://www.independent.co.uk/life-style/gadgets-and-tech/news/legal-right-fast-broadband-by-2020-universal-service-obligation-rural-internet-a6727156.html">make broadband a universal service obligation</a> that would put broadband on the same footing as the water supply. But such statements are two-a-penny, while the decisions and resources needed to make them a reality are sadly scarce.</p>
<p>The government acknowledges the enormous demand for fast broadband – <a href="https://www.gov.uk/government/publications/the-digital-communications-infrastructure-strategy/the-digital-communications-infrastructure-strategy">growing around 40% every year</a> – but it has adopted the wrong approach to meeting that demand.</p>
<p>If the communications network is to be considered as <a href="http://www.cpni.gov.uk/about/cnic">critical national infrastructure</a>, as suggested by the <a href="http://www.parliament.uk/business/committees/committees-a-z/lords-select/digital-skills-committee/news/report-published/">House of Lords</a> and the prime minister, then investment must be considered over the long term. Yet the current strategy only makes sense for the private sector communications industry. Just as the shareholder value of a water company is based on profits from its customers rather than the public health benefit of a fresh water supply, shareholders of communications companies consider only short-term financial return from customers, rather than the national economic return of a truly digital economy.</p>
<p>With 95% of UK homes expected to have 24Mbps by 2017, the updated aim for every home to have 10Mbps (megabits per second) broadband by 2020 is a welcome increase from the <a href="http://www.ispreview.co.uk/index.php/2012/11/ofcom-report-finds-65-of-uk-premises-can-get-superfast-broadband.html">previous minimum of 2Mbps</a>. But this is orders of magnitude behind what’s available: more than half of Japanese and South Korean homes are connected to a fibre service faster than 1Gbps (gigbits per second) – and countries as diverse as Estonia, Turkey and Denmark are investing in fibre services <a href="http://telecoms.com/7807/danish-call-for-big-bang-approach-to-fibre/">faster than 10Gbps</a>. </p>
<p>Contrast this with UK telecoms regulator Ofcom’s definition of high-speed (or “superfast”) broadband as <a href="http://stakeholders.ofcom.org.uk/binaries/research/infrastructure/2014/IR_3.pdf">above 30Mbps</a>, while the OECD specifies anything below 50Mbps as “mid speed”. We are aiming far too low. Transformative changes to people’s lives through new digital services in personalised medicine, education and communication are most likely to be pioneered in those societies with the widest roll-out of high-speed broadband – already more than 1,000 times higher than UK recommendations.</p>
<h2>Don’t believe the advertising</h2>
<p>There have been <a href="http://www.bbc.co.uk/news/technology-33164725">complaints</a> about how broadband products are advertised, using the weaselly expression “up to” a certain speed to hide an enormous range of service quality. The same applies to the use of “fibre service”. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/102641/original/image-20151120-428-1eyp2nz.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The irony is that fibre has literally only reached this cabinet.</span>
<span class="attribution"><span class="source">Rept0n1x</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The <a href="http://www.oecd.org/sti/broadband/oecdbroadbandportal.htm">OECD definition</a> is where the entire circuit from network backbone through the local exchange to a customer’s property is via fibre-optic cable (known as fibre-to-the-home or fibre-to-the-premises). This is the fastest available. But in Britain, the broadband roll-out carried out by Openreach under the government’s <a href="https://www.gov.uk/guidance/broadband-delivery-uk">Broadband Delivery UK</a> provides fibre-optic connections only to the telephone street cabinets (fibre-to-the-cabinet). This means that the “last mile” connection to the customer’s house – which may be far more than a mile – is through copper telephone cable, resulting in a dramatic drop in speed. </p>
<p>The same applies to Virgin Media advertising broadband via its cable television network as “fibre”. BT’s <a href="http://www.computerweekly.com/news/4500255882/Is-Gfast-the-answer-to-the-UKs-fibre-vs-copper-debate">upgrade to G.Fast</a>, a mix of fibre-optic and copper cable that promises speeds “up-to” 1Gbps, is still a fibre-to-the-cabinet solution. That means a costly, lengthy cabinet upgrade process that will ultimately still only provide a strongly distance-dependant service: those far from the exchange and poorly served before will be poorly served after.</p>
<p>Calling these a “fibre service” hides the fact that they are at best a stop-gap measure, the costs of which would, in the long term, be better spent on building a nationwide, high–capacity fibre-optic infrastructure that will stand the UK well into the future. True fibre-to-the-home could be deployed today with a <em>starting</em> speed of 1Gbps and seamless upgrades to higher capacities – and would deliver the advertised speed regardless of distance from the exchange. This would allow real-time streaming of uncompressed, broadcast-quality 4k television – but, more importantly, it would fundamentally change the way we do things online. Sweden has the third largest penetration of fibre in the world at 40%; the UK’s fibre-to-the-cabinet does not even make the chart.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/103918/original/image-20151201-26568-pgvt61.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fibre connections as percentage of total broadband connections among countries reporting fibre services, Dec 2014.</span>
<span class="attribution"><a class="source" href="http://www.oecd.org/sti/broadband/oecdbroadbandportal.htm">OECD</a></span>
</figcaption>
</figure>
<p>Of course, the initial installation cost is higher and depends on the exact solution used. But the overall cost of a complete fibre-to-the-home network, ignoring any existing infrastructure, is still less than half the cost of HS2, and would provide significant cost savings in the long run. Recent <a href="http://eandt.theiet.org/news/2013/dec/broadband-survey.cfm">surveys by the IET</a> suggest this would be a considerably more popular investment than HS2 – and arguably it would provide a more significant return on investment to a much greater number of people.</p>
<h2>Pushing the frontiers</h2>
<p>Fibre is the future – and the <a href="http://www.unloc.net">UNLOC</a> research programme based at UCL and Aston University is working alongside many industrial partners to push the limits of current technology. This year UNLOC has demonstrated record transmission distances of four terabits per second over 2,000km using a novel all-optical signal processing technique. </p>
<p>In May UNLOC was joint organiser of a discussion meeting at the Royal Society entitled <a href="https://royalsociety.org/events/2015/05/communication-networks">Communication networks beyond the capacity crunch</a>, highlighting the growing concern among academics and industry that broadband demand will outstrip network capacity. This applies for wired telecoms but even more so for mobile phone networks. The government must take all possible steps to encourage the best use of new technologies and high-capacity fibre-to-the-home.</p>
<p>This will require leadership, but not necessarily significant funding. For example, planning rules could be updated so that newly built homes and premises must come with a fibre-optic connection installed, government subsidised installations should be fibre-to-the-home, broadband speed targets redefined to exceed the OECD definition and advertising should properly acknowledge the benefits of true fibre-to-the-home products. This is possible: the London Borough of Wandsworth administration recently <a href="http://www.ispreview.co.uk/index.php/2015/09/battersea-council-estate-homes-hail-1086mbps-fibre-broadband-pilot.html">connected its social housing to a 1Gbps fibre service</a>, while <a href="http://www.computerweekly.com/news/4500256876/Gigaclear-breaks-ground-on-BDUK-FTTP-networks">rural Berkshire is laying fibre</a>.</p>
<p>In the US, communities and municipalities failed by their telecoms providers have <a href="http://www.theguardian.com/world/2014/aug/30/chattanooga-gig-high-speed-internet-tech-boom">taken matters into their own hands</a> and installed their own fibre networks. The government should support those wishing to to so in the UK by requiring that telecoms firms offer a collective fibre-on-demand product. There’s also a place for a discussion around granting network providers a share in the profits of firms whose paid-for content is delivered over their networks – providing an incentive for further investment.</p>
<p>A national fibre-to-the-home network would offer significant long-term return, and can be achieved with a range of light-touch regulations, policies and guidance, or via a major national infrastructure program. Both courses would propel the UK to the forefront of the global digital economy, where it needs to be.</p><img src="https://counter.theconversation.com/content/50941/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Ellis was founding director of Pilot Photonics, an Irish company specialising in optical frequency combs. He receives EPSRC, Royal Society and EU funding, and has previously received funding from Science Foundation Ireland and Enterprise Ireland. He is adjunct Professor at Dublin City University and University College Cork.
</span></em></p><p class="fine-print"><em><span>Polina Bayvel receives EPSRC and EU funding. </span></em></p><p class="fine-print"><em><span>Sergei Turitsyn receives EPSRC funding for the UNLOC project.</span></em></p>Whatever BT, Virgin Media and other telecoms firms may say, the only future-proof network is a fibre-optic from door-to-door.Andrew Ellis, Professor of Optical Communications, Aston UniversityPolina Bayvel, Professor of Optical Communications & Networks, UCLSergei Turitsyn, Professor in Photonics, Electrical, Electronic and Power Engineering, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/499362015-11-03T11:07:23Z2015-11-03T11:07:23ZIn our Wi-Fi world, the internet still depends on undersea cables<figure><img src="https://images.theconversation.com/files/100571/original/image-20151102-16507-fs65z0.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cables crisscross the oceans carrying your internet info.</span> <span class="attribution"><a class="source" href="http://www.submarinecablemap.com">Telegeography Submarine Cable Map</a></span></figcaption></figure><p>Recently a digital blackout <a href="http://surfacing.in/?place=nukualofa-tonga">in Tonga</a> — caused by the <a href="https://phys.org/news/2019-01-tonga-country-facebook-youtube.html">severing of the country’s only undersea cable</a> — generated widespread recognition of the submerged systems our connected world depends upon.</p>
<p>Not many people realize that undersea cables transport nearly <a href="https://books.google.com/books?id=LQDXAQAAQBAJ&pg=PA362&dq=submarine+telecommunications+cables&hl=en&sa=X&ved=0CEMQ6AEwBGoVChMI5Pm8_oPyyAIVBG4-Ch379Al9#v=onepage&q=99&f=false">100 percent of transoceanic data traffic</a>. These lines are laid on the very bottom of the ocean floor. They’re about as thick as a garden hose and carry the world’s internet, phone calls and even TV transmissions between continents at the speed of light. A single cable can carry tens of terabits of information per second. </p>
<p>While researching my book “<a href="https://www.dukeupress.edu/The-Undersea-Network">The Undersea Network</a>,” I realized that the cables we all rely on to send everything from email to banking information across the seas remain largely unregulated and undefended. Although they are laid by only a few companies – including the American company SubCom and the French company Alcatel-Lucent – and often funneled along narrow paths, the ocean’s vastness has often provided them protection. When one is broken, as the Tonga cable was this week, data traffic comes to a halt.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=543&fit=crop&dpr=1 754w, https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=543&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/100398/original/image-20151030-16532-1tr7ho1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=543&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">2015 map of 278 in-service and 21 planned undersea cables.</span>
<span class="attribution"><span class="source">Telegeography</span></span>
</figcaption>
</figure>
<h2>Far from wireless</h2>
<p>The fact that we route internet traffic through the ocean – amidst deep-sea creatures and hydrothermal vents – runs counter to most people’s imaginings of the internet. Didn’t we develop satellites and Wi-Fi to transmit signals through the air? Haven’t we moved to the cloud? Undersea cable systems sound like a thing of the past. </p>
<p>The reality is that the cloud is actually under the ocean. Even though they might seem behind the times, fiber optic cables are actually state-of-the-art global communications technologies. Since they use light to encode information and remain unfettered by weather, cables carry data faster and cheaper than satellites. They crisscross the continents too – a message from New York to California also travels by fiber optic cable. These systems are not going to be replaced by aerial communications anytime soon.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/100394/original/image-20151030-16535-1rv67sd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A tangled cable caught by fishermen in New Zealand.</span>
</figcaption>
</figure>
<h2>A vulnerable system?</h2>
<p>The biggest problem with cable systems is not technological – it’s human. Because they run underground, underwater and between telephone poles, cable systems populate the same spaces people do. As a result, they’re accidentally broken all the time. Local construction projects dig up terrestrial lines. Boaters drop anchors on cables. And submarines can pinpoint systems under the sea. </p>
<p>Most media coverage about these systems has been dominated by the question of vulnerability. Are global communications networks really at risk of disruption? What would happen if these cables were cut? Should we all be worrying about a digital blackout – whether caused by accident or terrorists? </p>
<p>The answer to this is not black and white. Any individual cable is always at risk, but likely far more so from boaters and fishermen than any saboteur. Over history, the single largest cause of disruption has been people unintentionally dropping anchors and nets. The <a href="https://www.iscpc.org">International Cable Protection Committee</a> has been working for years to prevent such breaks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/100395/original/image-20151030-16532-1ouvfiw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An undersea cable lands in Fiji.</span>
<span class="attribution"><span class="source">Nicole Starosielski</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>As a result, cables today are covered in steel armor and buried beneath the seafloor at their shore-ends, where the human threat is most concentrated. This provides some level of protection. In the deep sea, the ocean’s inaccessibility largely safeguards cables – they need only to be covered with a thin polyethylene sheath. It’s not that it’s much more difficult to sever cables in the deep ocean, it’s just that the primary forms of interference are less likely to happen. The sea is so big and the cables are so narrow, the probability isn’t that high that you’d run across one.</p>
<p>Sabotage has actually been rare in the history of undersea cables. There are certainly occurrences (though none recently), but these are disproportionately publicized. The World War I <a href="https://en.wikipedia.org/wiki/Fanning_Raid">German raid of the Fanning Island cable station</a> in the Pacific Ocean gets a lot of attention. And there was <a href="http://www.economist.com/node/10653963">speculation about sabotage</a> in the cable disruptions outside Alexandria, Egypt in 2008, which cut 70 percent of the country’s internet, affecting millions. Yet you hear little about the regular faults that occur, on average, about 200 times each year.</p>
<h2>Redundancy provides some protection</h2>
<p>The fact is it’s incredibly difficult to monitor these lines. Cable companies have been trying to do so for more than a century, since the first telegraph lines were laid in the 1800s. But the ocean is too vast and the lines simply too long. It would be impossible to stop every vessel that came anywhere near critical communications cables. Nations would need to create extremely long, “no-go” zones across the ocean, which itself would profoundly disrupt the economy. Even then, the cables could still be at risk from undersea landslides.</p>
<p>There are only <a href="http://submarinecablemap.com">several hundred cable systems</a> that transport almost all transoceanic traffic around the world. And these often run through narrow pressure points where small disruptions can have massive impacts. Since each cable can carry an extraordinary amount of information, it’s not uncommon for an entire country to rely on only a handful of systems. In many places, like Tonga, it takes only a single cable cut to take out large swathes of the internet. If the right cables were disrupted at the right time, it could disrupt global internet traffic for weeks or even months.</p>
<p>The thing that protects global information traffic is the fact that there’s some redundancy built into the system. Since there is more cable capacity than there is traffic, when there is a break, information is automatically rerouted along other cables. Because there are many systems linking to the United States, and a lot of internet infrastructure is located here, a single cable outage is unlikely to cause any noticeable effect for Americans.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/100400/original/image-20151030-16527-17y489n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Surfacing.in is an interactive platform developed by Erik Loyer and the author that lets users navigate the transpacific cable network.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Any single cable line has been and will continue to be susceptible to disruption. And the only way around this is to build a more diverse system. But as things are, even though individual companies each look out for their own network, there is no economic incentive or supervisory body to ensure the global system as a whole is resilient. If there’s a vulnerability to worry about, this is it.</p>
<p><em>This is an updated version of an article originally published on Nov. 3, 2015.</em></p><img src="https://counter.theconversation.com/content/49936/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicole Starosielski does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The cloud lies under the ocean. Thin cables about as big around as a garden hose traverse the Earth’s oceans carrying all our intercontinental internet data.Nicole Starosielski, Assistant Professor of Media, Culture and Communication, New York UniversityLicensed as Creative Commons – attribution, no derivatives.