Subsea Cables & Internet Infrastructure

***Communication subsea cable reliability has skyrocketed from 1 fault per annum for every 500 nautical miles during the 1850-1914 period to 1 fault a year for every 4,729 nautical miles today. A nautical mile is 1.85 kilometers or 1.15 US miles. ***The chart shows a stationary long run mean of 200 repairs per year despite a 50% increase in route mileage from 1 million to 1.5 million kilometers today. META estimates 86% of faults caused by fishing and anchor incidents. ***This remarkable improvement is a combination of better geophysical surveys, better armored cables, ability to do deeper burials, better public awareness of where the cables are located, and a higher premium placed in design on reliability.

META's chief AI scientist, Yann LeCun, explains why neither Google nor META has deployed something like ChatGPT despite developing many of the underlying techniques. "I mean you have to realize that most of the underlying techniques used in ChatGPT were invented at Google and META. If you are META or Google, you can think about putting out a system like this that you know is going to spew nonsense and you know because you are a large company you have lot to lose by people making fun of you for that." Click for the complete interview : https://www.youtube.com/shorts/bdYylvhZ9T0

Google uses fans to blow warm air over water in its data centers for cooling. This takes advantage of water's high heat capacity which makes it far more efficient than standard air conditioning. These researchers have designed membranes that maximize the efficiency of cooling via evaporation. The membranes are positioned right over the circuits and pull water in via capillary action. The membranes have successfully handled up to 800 watts of heat per square centimeter. The obvious unanswered questions include production cost, ease of integrating into servers, and the material's life span.  https://techxplore.com/news/2025-06-evaporative-cooling-tech-curb-centers.html

Rumors have been floating around for several months about a successor project to AAE1 known as AAE2. Like AAE1, the key goal is to connect Hong Kong and Singapore to India, the Middle East, and Europe. The core consortium includes PCCW, Telecom Egypt, Omantel, and Sparkle. Just like other recent projects such as SMW6, AAE2 will avoid the Red Sea. Instead, the cable will land in Oman, then traverse Saudi Arabia and Egypt to reach the Red Sea. I applaud the cable's designers for ditching the Red Sea. It was long overdue. However, a more logical approach is to avoid Egypt all together. The Saudi Arabian desert will be expensive. The consortium has increased both capex and opex further by using Egypt for transit. Egypt treats subsea cables the way a toll road treats cars. It extracts a monopoly fee from them. It makes no sense given that Israel has a competitive telecom market versus Egypt's pseudo competitive market.  Another interesting design feature is that Italy was mentioned ...

The three fibre pair Quintillion cable went live in 2017. Its current throughput is 10 Tbps per fibre pair. It includes terrestrial back haul from Prudhoe Bay down to Fairbank, Alaska, in the middle of the state. The cable was deeply buried with an average depth of 3.7 meters with bore pipes used to bring the fibre pair ashore to the manhole. Each landing threads the fibre optic cable through steel conduit at least 18 meters under the sea floor up to 1.6 kilometers offshore. This was accomplished via horizontal directional drilling. Project cost was around $150 million. The cable is a godsend for these Alaskan communities and was built to top notch engineering standards. But it still suffers from ice scouring incidents where icebergs cut through the sea floor and have severed or severely damaged the cable. A major outage occurs roughly once a year, but the real problem is the repair time. It is simply not economical for a subsea cable to own an icebreaker or to risk a cable ship's ...

Capacity: 1x 100G A-End: Mombasa B-End: Marseille Term: 12 Months MRC: $ 58,500 NRC: $ 25,500 Capacity: 1x 100G A-End: Djibouti B-End Marseille Term: 12 Months MRC: $30,575 NRC: $25,500

Anjana is a half terabit META cable landing at Myrtle Beach, South Carolina, and Santander, Spain. It is well known that the design capacity is 480 Tbps based on 24 fibre pairs. Here are some new details: A. There are 89 optical amplifiers space 80 kilometers apart. That's 48 US miles and is near the amplifier distance limit for high capacity systems. B. The presenter said it uses 8,000 volts of DC. I ask the engineers reading this post to tell me if this makes sense. C. The standard for a reliable subsea network is one bad bit in a trillion or less. In other words, a bit error equal or less than 10 to the minus 12 power.

Medusa is seeking to extend its Mediterranean subsea cable network to Africa's West coast. Full funding has not been secured. Rumor has it that Medusa is trying to get the balance required from Hong Kong investors. CEO vehemently denies it. System would have 16 fibre pairs and extend down the West coast of Africa to Capetown. There are a couple of factors driving Medusa's interest. Although Equiano dropped many branching units in the water, there have been few takers. This means most West Coast countries have only one modern cable, 2Africa, for transport. Moreover, it is likely that 2Africa capacity will go fast. A quarter belongs to Facebook. Moreover, there will be substantial migration from ACE and WACS to 2Africa due to the latter's superior reliability and much lower pricing. So it is likely 2Africa will be maxed out in 3 to 5 years. Another key driver is avoiding the Red Sea. Right now the 2Africa Marseille/Mombasa and Oman routes cannot be completed due...

I spoke very briefly with Tom McMahon at SubOptic 2025, whose design and civil engineering company has almost a 100% market share of Irish subsea fibre optic cable projects. Tom is spearheading an effort as an entrepreneur in conjunction with Orange to build the first Irish fibre optic subsea cable to bypass the UK and directly connect hyperscaler Ireland to the European Continent. Pisces has received two rounds of funding from the EU to financed research and design of the proposed cable. Frankly, I suspect the EU loves this project since it reduces the dependency of the Irish data centers on traversing the UK to reach EU member states. According to Tom, it's fully funded. Furthermore, the plan to sell all the fibres on the system and provide no lit services itself. My hunch is that it is partially funded, but is likely to get the money it needs and be built. I wish Tom and his team the best of luck. It's a cool project. Amazon just announced it is creating a separate European ...

I attended both SubOptic 2025 and a subsequent Carrier Community subsea cable event this week. This long shot dream came up in conversations. This 12 fibre pair project to connect Japan to Europe via the North Pole has formed a consortium together with a memorandum of understanding, but it has not secured financing or an anchor tenant. This is not surprising. Nordunet is the project's champion; it is a collaboration of the five national research and education networks of Denmark, Finland, Iceland, Greenland, and Finland. The cable project is confusing because the vision is to have two cables, one using the shortest path possible, which is via the North Pole, and another cable for resiliency that snakes through the Northwest passage and closely follows the Canadian shore. Some sources estimate that the Northwest passage cable would cost $1.1 billion. Obviously maintenance fees would be enormous. Today there is no cable ship designed for the North Pole. The survey alone would require...

Capacity: 1x 100G A-End: Mombasa B-End: Marseille Term: 12 Months MRC: $ 58,500 NRC: $ 25,500 Capacity: 1x 100G A-End: Djibouti B-End Marseille Term: 12 Months MRC: $30,575 NRC: $25,500

 Far right is a 1920s era hybrid telegraph/telephone cable. Analogue copper transmission. Next to it is 1984 coaxial telephone cable.

Despite what we think, telecom wholesale service is not really a tech industry, at least not in leadership. Engineers, scientists, technicians, mathematicians, and computer scientists lead the real tech companies. Google is an excellent example. Sergey Brin and Steve Paige, two Stanford educated computer scientists, founded the company. German companies almost always select mechanical engineers to lead them. Obviously there will be cases of generalists who do quite well. Bjarni Thorvardarson was not a STEM graduate, but he has a critical, yet open mind and led Hibernia out of bankruptcy to a $610 million sale sale to GTT. He accepted a sales force initially composed of four sales contractors who had no salaries, but received 10% of net revenue, (gross revenue minus third party network costs), used a contract manager to handle standard NSA and MSA negotiations as opposed to a lawyer, and took the daring step of building the new, ultra-low latency Express cable in an era o...

EXA has deployed G.652d fibre across much of its European backbone with the important routes receiving priority. Chart below shows the paths that have been upgraded. EXA's western European network consists largely of the Interoute assets plus a Bulgarian company that had fibre and conduit into Turkey. It is a highly dense network that gives EXA's Atlantic cables and Trans-Atlantic capacity (it owns a fibre pair on Dunant as well as some capacity on Amitié and other cables) the ability to deliver traffic from Chicago and Equinix all the way to Instanbul. This dense footprint allows to deliver traffic at lower costs then its main competitor, Telxius. The carrier has the same basic reasons to upgrade as EUNetworks, namely fibre depletion, hyperscaler demand for long haul dark fibre, and the improved performance of modern fibre with less bending and linear attenuation. Its marketing emphasizes that it is deploying G.652d fibre, but I believe this is just marketing to reassure pot...

With most European long haul fibre having been deployed in the 1998-2002 periods, it is not surprising that after 20 years that carrier upgrades were in the cards. There are several reasons. One is fibre exhaustion. Secondly, although fibre itself does not rapidly depreciate because glass is highly stable, technology has evolved. For one, the optimal ILA spacing has sharply increased due to the advent of ultra-low loss fibre, which has attenuation of .2 dB or even less per kilometer. Since most repeater huts are old, replacing closely spaced old ILAs with new, more widely spaced facilities lowers power and equipment costs long term. With fewer ILAs, less can go wrong. There were other factors as well driving EUNetworks' upgrade decision. Although old fibre is generally in remarkably good shape, there are often problems at joints. At these locations, the fibre pairs must be removed from the cable for splicing. Moisture often penetrates these joint enclosures. It attacks and erodes t...

During most of my telecom career terrestrial long haul fibre was synonymous with the ITU's G652 standard. This is single mode optical fibre that has zero chromatic dispersion at the 1310 nanometer wavelength and good wavelength performance in the 1260 to 1625 nanometer range. This include the O, E, S and workhorse C bands. G.652d fibre quickly became the de facto standard for long haul terrestrial fibre optic networks. The G.652 standard was introduced in 1984. Its motivation was a dual purpose optical fibre suitable for data centers and long haul. Most optical equipment for internal data center traffic transmitted in the O band, which ranges from 1260 to 1390 nanometers. But long haul traffic faces significant attenuation as distances grow. This required repeaters, another source of capex and opex expense. It was already known that attenuation or the diminishing of light's intensity was minimized in glass at 1550 nanometers. The versatility of the G.652 standard made it hugel...

I An optical fibre has three structural components. The glass core transmits the light. It is the optical highway that the light travels. If the light is single mode, the core is 8.3 microns. A single mode fibre can be thought of as a single lane road. If the light is multi-mode, the core is 50 or 62.5 microns.  The 125 micron cladding is also glass. It is made ofglass that keeps the core glass from leaking light as long as the angle of incidence is not too big. The buffer consists of a hard and soft layer of plastic, often urethane acrylate. The soft layer surrounds the cladding and cushions it. The hard layer prevents abrasion. For a more complete explanation, click on https://learn.aflglobal.com/home/the-basic-structure-of-optical-fiber. II Modes of Optical Strands A single mode strand has one path. Think of it as a straight path down which the light travels. To keep the path straight the diameter is relatively small at 8.3 microns. Multimode glass allows the glass to trave...

Juno is the Queen of the Olympian gods in Roman Mythology. This 20 fibre pair cable has design capacity of 320 Tbps, which makes it the highest capacity subsea network to connect the US to Asia. It lands at Grover Beach, California, and also has Japanese landings at Shima and Minami-Boso. NTT is the project's main backer and owner. The carrier clearly felt that two Japanese branches along with three cable landing stations (Softbank Maruyama, NTT Shima, and NTT Minami-Boso) would significantly improve resiliency given Japan's reputation for earthquakes and other natural disasters such as tsunamis. As is usual for a NTT project, it created a standalone company known as SerenJuno in which it has majority ownership to minimize risk. This way any misfortunes would not result in the parent company having financial liabilities. NTT is also extremely reserved about revealing capacity owners on the system. I have learned that PCCW is on the system. Details Ownership: NTT and Mitsui. Cap...

 1. Damage to cables is often the result of a cascade of events. For example, the 2006 Taiwan Earthquake pushed coastal sediments down a steep slope and triggered a massive landslide that traversed over a hundred kilometers. In many cases snapping deep sea cables like they were toothpicks. The sediment build up is due to Taiwan's heavy rains that carry eroded soil to the sea. 2. Lots of subsea faults arise from events that unfold over years such as deep sea abrasion of the outer sheaths of a cable. A cable may rub against a rough surface on the ocean floor for years until the polyethylene layer and the wound steel strands are removed and water hits the copper power conductor. 3. Another interesting example is the Congo Canyon where the Congo river deposits sediments offshore that high spring tides or flooding push down the undersea canyon and crush subsea cables. 4. Volcanoes during discharges have buried cables in molten lava. Also pose a danger to cable landing stations and terre...

In a recent interview META subsea engineers suggested their next project would be a 1 Petabit Trans-Atlantic cable. They pointed to three possible ways of accomplishing it: multicore fibre, use of the C and L spectrum bands, and 50 fibre pair SDM. Pros and Cons 1. Multicore is subject to cross talk. Right now the only multicore cable is the Taiwan-Phillipines-US cable scheduled to go live this year. A Google project with NEC as the vendor, it has two cores per fibre strand and 26 Tbps total per fibre strand or 13 Tbps per core. The challenge is cross talk. The light spills from one core to the other and vice versa. Obviously this distorts the signals and at high transmission rates the distortions become greater and greater and the signal-to-noise ratio disintegrates. The advantage of multicore fibre is that no redesigning of the optical amplifiers is required. Since everyone acknowledges that SDM alone is unlikely to surpass the half terabit mark, Google is obviously interested in mult...