Key Takeaways
- Submarine fiber optic cables, unseen and hidden deep beneath the ocean, are the backbone of the internet, carrying over 99% of all international data.
- These cables, dating back to the 1850s, have evolved from copper wires to modern fiber optic cables that can transmit tens of terabits of data per second.
- The global submarine cable network spans across all continents except Antarctica, with high concentration in regions with high data traffic.
- Tech giants like Google, Facebook, Microsoft, and Amazon are investing heavily in these cables to meet the surging demand for data and gain more control over global internet infrastructure.
- Despite their importance, submarine cables face many challenges including natural hazards, man-made threats, geopolitical tensions, and security risks.
The Invisible Cables That Connect Our World
Imagine being able to instantly video call a friend on the other side of the planet, binge watch your favorite Netflix series, or collaborate with colleagues scattered across different continents – all with the click of a button. This incredible feat of global connectivity that most of us take for granted is made possible not by satellites in the sky, but by an extensive network of cables crisscrossing the ocean floor. Though these submarine fiber optic cables are hidden deep beneath the waves, they form the backbone of the internet, carrying over 99% of all international data traffic.
A Brief History of Submarine Cables
The idea of using cables to transmit information across oceans dates back to the 1850s, long before the internet existed. The first submarine telegraph cable was laid across the English Channel in 1850, enabling the exchange of telegraphic messages between the UK and France.
In 1866, after several failed attempts, the first successful transatlantic telegraph cable was completed, stretching nearly 2,000 miles from Ireland to Newfoundland. This marked the beginning of instantaneous communication between Europe and North America that previously relied on ships, reducing the time to transmit a message from ten days to just a few minutes.
These early submarine cables used copper wires to carry electrical telegraphic signals. In the 1950s, coaxial cables with polyethylene insulation and vacuum tube repeaters enabled the first transatlantic telephone cables. The first transatlantic telephone cable, TAT-1, was laid in 1956 between Scotland and Newfoundland, providing 36 telephone circuits.
The game changer came in the late 1980s with the development of fiber optic technology. Instead of copper wires, these cables used hair-thin strands of glass fibers that could transmit data via pulses of light, dramatically increasing the speed and capacity. In 1988, the first transatlantic fiber optic cable TAT-8 was installed, capable of carrying 40,000 simultaneous phone calls – ten times more than the last copper cable.
Anatomy of a Modern Submarine Cable
Today’s submarine fiber optic cables are marvels of engineering, designed to withstand the harsh conditions of the deep sea. A single cable is typically about the size of a garden hose, yet can contain up to 24 pairs of glass fibers, with each pair able to carry tens of terabits of data per second.
The optical fibers are protected by layers of petroleum jelly, copper shielding, stranded steel wires for strength, and polyethylene insulation. The copper layer conducts electricity to power the repeaters placed at intervals of 50-100km along the cable to boost the optical signals. The cables are further encased in galvanized steel wire armor and an outer polyethylene sheath to resist corrosion, abrasion, and shark bites.
Bridging Oceans at Lightning Speed
Submarine cables span vast distances across the ocean floor, connecting every continent except Antarctica. The longest cable currently in service is the SEA-ME-WE 3 system, stretching over 39,000 km from Germany to Australia and Japan.
Even at these incredible lengths, a cable can carry data at nearly the speed of light – around 200,000 km per second. That means an email sent from New York can reach Sydney in just 60 milliseconds, faster than the blink of an eye.
The total submarine cable network is now long enough to circle the Earth more than 12 times. TeleGeography, a telecommunications market research firm, estimates there are over 1.3 million kilometers of submarine cables in service globally as of 2021.
The Global Submarine Cable Network
The global web of submarine cables is not evenly distributed. The highest concentration of cables is found in the North Atlantic, linking North America and Europe – the two largest markets for data traffic. Other high-density routes include the transpacific cables connecting North America to Asia, and the cables ringing the coasts of Europe, East Asia, and the Middle East.
In contrast, regions like Africa, South America, and the South Pacific have far fewer cables, reflecting their historically lower levels of internet connectivity and data demand. However, this is starting to change with a recent boom in cable construction to these underserved markets.
Interactive maps like TeleGeography’s Submarine Cable Map provide a fascinating visualization of the world’s undersea cable network. The map depicts over 500 cable systems that are currently active or under construction, along with their landing points in over 100 countries.
Some of the highest capacity routes on the map include:
- The trans-Atlantic route, with over 20 cable systems connecting North America and Europe, such as the MAREA, AEC-1, and Hibernia Express cables.
- The trans-Pacific route, with cables like JUPITER, New Cross Pacific, and Hong Kong-Americas connecting Asia and North America.
- The Europe-Asia route through the Mediterranean Sea, Red Sea, and Indian Ocean, served by cables like SEA-ME-WE 3, SEA-ME-WE 4, and AAE-1.
- The intra-Asian route, with a web of cables like the Asia-Pacific Gateway, SJC, and APCN-2 connecting the major hubs of Singapore, Japan, Hong Kong, and Taiwan.
The map also highlights the critical role of certain countries and cities as cable landing hubs, owing to their strategic geographic locations along major data traffic routes. Some of the top hubs include:
- The United States, with cable landings on both its east and west coasts connecting to Europe, Latin America, and Asia. Key landing points include New York, New Jersey, Florida, California, and Oregon.
- The United Kingdom, serving as a major hub for trans-Atlantic cables, with key landings in Cornwall and Scotland.
- Singapore, a global data center hub with over 20 cable landings connecting to the rest of Asia, Australia, the Middle East, and Europe.
- Japan, with multiple cable landings along its coast connecting to Asia and North America, especially in the cities of Chikura and Kitaibaraki.
- Egypt, a critical chokepoint with cables traversing between the Red Sea and Mediterranean via overland routes to avoid the Suez Canal.
- France, where the city of Marseille has emerged as a key interconnection point for cables from Europe, the Middle East, Africa and Asia.
The Cable Boom: Big Tech’s Big Bet
The exponential growth in global internet traffic, fueled by bandwidth-hungry applications like video streaming, cloud computing, and the Internet of Things, has driven a boom in new submarine cable construction over the past decade.
But what’s different this time is who’s funding these multi-million dollar projects. While previous cable building cycles were dominated by telecom carriers, content providers like Google, Facebook, Microsoft and Amazon are now taking a leading role.
Faced with insatiable demand for data from their billions of users, these tech giants are investing in their own private undersea cables to gain more control over the global internet infrastructure. Google alone has backed at least 14 cables worldwide, including the 7,500-mile Grace Hopper cable connecting New York to Spain and the UK, which the company claims is the world’s first to use novel “fiber switching” technology to increase reliability.
Facebook has partnered with leading regional carriers to build 2Africa, which will be the longest subsea cable system in the world connecting Europe, the Middle East, and 21 landings in 16 countries in Africa. The 45,000-kilometer cable will deliver more than the total combined capacity of all subsea cables serving Africa today.
Microsoft, Amazon and other cloud providers are also investing in proprietary cables to connect their global data centers. The Marea cable, a joint project between Microsoft, Facebook and Telxius, is the highest capacity cable crossing the Atlantic, with eight fiber pairs and an initial estimated design capacity of 160 Tbps.
Powering the Global Economy
Submarine cables are the unsung heroes of our digitally connected world. They not only make the internet possible, but power global business, commerce and finance. It’s estimated that undersea cable networks carry over $10 trillion in financial transactions each day.
For many countries, losing connectivity due to a cable fault can be crippling economically. When submarine cables were cut by an undersea earthquake in 2006, it plunged India, Malaysia, Singapore, and several Middle Eastern countries into digital darkness. India lost over half its internet capacity, wreaking havoc on its outsourcing industry.
Redundancy is critical to avoid such catastrophic outages. Important routes are served by multiple cables following different paths to mitigate risk. Many coastal countries are served by several cable landing points to distribute failure points. And companies can purchase capacity on numerous cables to ensure continuity.
Challenges Under the Sea
For all their importance, submarine cables face many natural and man-made threats:
- Underwater earthquakes, landslides and currents can snap or bury cables
- Fishing trawlers and ship anchors account for two-thirds of all cable faults
- Sharks and other fish have been known to bite cables, possibly mistaking electromagnetic fields for prey
- Thieves have tried to steal cables for their copper
- Spying agencies have tapped cables to intercept communications
When damage occurs, specially-equipped cable repair ships are dispatched to the break site. Using submersibles or grapnels, they retrieve the cable ends and splice in a new section on the ship’s deck – a process that can take days to weeks depending on the extent of the damage and weather conditions.
To safeguard against future faults, cable routes are carefully surveyed to avoid hazards, buried beneath the seabed in shallow waters, and marked on maritime charts. The International Cable Protection Committee (ICPC) also works with industries and governments to raise awareness of cable locations and best practices.
Strategic Importance and Geopolitical Risks
With the world becoming more digitally interconnected, submarine cables are seen as strategic assets and potential targets in geopolitical disputes. Most intercontinental internet traffic flows through a few critical chokepoints, such as the Suez Canal, Strait of Malacca, and Luzon Strait.
Potential Disruptions
Any disruption at these critical junctures, whether due to an anchor drag, a natural disaster, or a deliberate attack, could have global repercussions. For instance, damage to cables running through the Suez Canal could hinder connectivity between Europe, the Middle East, and Asia.
Security Concerns and Espionage
There are growing concerns about foreign powers exploiting vulnerabilities in submarine cable infrastructure for espionage or sabotage. There have been instances of Russian ships allegedly engaging in suspicious activities near cables in the Atlantic. The U.S. has long been known to have the capability to tap undersea cables for intelligence gathering, as revealed by Edward Snowden.
Vulnerabilities and Protection Measures
Apart from the cables themselves, the shore-end landing stations, where they connect to domestic networks, are seen as weak points. Experts warn these could be targeted by state actors or terrorist groups to disable communications. Consequently, some countries now restrict cable landings and equipment purchases from foreign firms deemed a security risk.
Impact of Geopolitical Pressures
Amid geopolitical pressures, the U.S. has urged its allies to exclude Chinese telecom giant Huawei from their 5G networks, citing surveillance concerns. Huawei Marine, the company’s submarine cable subsidiary, has been involved in building or repairing nearly 100 cables globally. However, following the U.S. pressure campaign, Huawei has divested the unit to a Chinese fiber optic cable maker.
Bridging the Digital Divide
Despite the global reach of submarine cables, internet access is still far from equal. Many developing nations, especially in Africa and the Pacific islands, remain largely disconnected due to the high cost of infrastructure.
Over the last decade, a boom in cable construction has aimed to close this gap. Ambitious projects like 2Africa, funded by a consortium led by Facebook, will add 45,000 km of cables around Africa, doubling the continent’s capacity. Many island nations are getting connected for the first time, enabling advances in education, healthcare, commerce and quality of life.
Efforts are also underway to leverage submarine cables for environmental monitoring and disaster warning. The SMART cable initiative proposes integrating temperature, pressure and seismic sensors into future telecom cables to collect real-time oceanographic data. This could revolutionize our understanding of ocean circulation, sea level rise, and tsunami detection.
The Future is Bright
As the world becomes increasingly digital, our reliance on submarine cables will only deepen. Rising demand for 5G networks, streaming video, cloud computing and the Internet of Things will drive a projected 40% compound annual growth in international bandwidth.
To meet this demand, new cables are pushing the boundaries of performance using more fiber pairs, advanced optical transmission technologies, and AI-optimized network management. A planned trans-Pacific cable aims to achieve a record-breaking capacity of 500 terabits per second.
At the same time, some experts caution that the consolidation of data traffic onto a smaller number of mega-cables could pose risks to the resiliency of the internet. Satellites and other emerging technologies may help provide complementary capacity and reduce our dependence on any single cable system.
Ultimately, the story of submarine cables is one of continual progress in the face of immense challenges.
