Subsea Cables & Internet Infrastructure

Each fibre strand consists of the core and the cladding. The core is like a one way road for the light to traveland cladding are the guardrails that prevent it from escaping. The refractive index measures how fast light traverses a given medium. It is defined as the ratio of the speed of light in a vacuum to the velocity of light via the medium. The core has a higher refractive index than the cladding. As long as the refractive index differential is large enough, photons that hit the cladding at a critical angle or less will bounce back into the core. Physicists call this bouncing of light internal reflection. So the core/cladding structure is designed to preserve the optical power or amplitude of the wavelengths. It minimizes optical attenuation, the great enemy of optical networking along with chromatic and polar dispersion.  The bottom middle chart shows that optical attenuation, which reflects opposing forces, reaches a minimum in the C band. The C band is defined as wavelength...

 2Africa; Senegal/Portugal; 100G; $18.5K; 2 Years. WACS; Ivory Coast/Portugal; 10G; $8,250; 3 Years. 2Africa; Nigeria/South Africa; 100G; $24,750; 1 Year. Equiano; Nigeria/South Africa; 100G; $20K; 1 Year. Equiano; Nigeria/Portugal; 100G; $19.5K; 2 Year. 2Africa; Ghana/Nigeria; 100G; $23.5K; 1 Year. 2Africa; Ivory Coast/Portugal; 10G; $10,500; 1 Year. 2Africa; Ivory Coast/Portugal; 100G; $33.5K; 3 Year. Remarks: 2Africa CLS cross connects are $150 max. WACS cross connect charges are five digit.

Part 1 finished by noting that that the CLS in most cable systems has been downgraded to a building housing just the power feed equipment. This reflects the open cable model where each owner has fibre pairs or spectrum as opposed to a cut of the cable't lit capacity. A good example is 2Africa in Senegal. Most of the SLTEs (subsea line termination equipment) are collocated in the carrier neutral ONIX facility. But Facebook decided to put its SLTE in one of three N Plus data centers.  Another important element is the branching unit, which originally just took the main trunk's fibre pair and allocated them into two small trunks. TAT8, the first fibre optic cable, used a branching unit to land one fibre pair in the UK and the other in France. Branching units have evolved over time and most today have the ability to switch wavelengths and more recently fibre pairs. The advantages include being able to reroute traffic in case one branch fails. The branches are typically buried on the...

Benoit Kowalski gave the presentation at the event. The diagram below shows the standard subsea network architecture. The fibre optic cable and optical amplifiers are collectively called the wet segment. The rule of thumb is to bury the cable in waters a thousand meters or less deep. Approaching shore one has a choice. One can give bring the cable ashore using small boats. The cable initially lies exposed on the beach up to the beach manhole. Then the cable is buried from some point in the water up to the manhole where it is spliced into the front haul fibre that carries the signal to the cable landing station. From the CLS back haul fibre goes to a carrier neutral data center that serves as a point of presence (POP) or interconnection point. The other platinum-plated approach uses horizontal drilling to install a bore pipe from the manhole to a point on the sea floor offshore. This is much more expensive, but better protects the cable.  A couple of things to note. I...

Dr Kowalski is a Nokia employee who collaborates with ASN. His presentation on the first day of the conference is a good subsea cable primer.  The transmission equipment is known as the submarine line termination equipment or SLTE. It has three key components. Encoding involves taking the digital input and converting it into a series of laser commands according to the modulation scheme. FEC or forward error correction adds redundant bits called parity bits that help the far end FEC to detect and correct payload mistakes. It is a bit like a router creating the checksum field in the IP packet header. Once quality is control is completed, the laser sends the optical signal. Its ever weakening light travels the fibre until it is passively boosted by erbium doped fibre in the amplifier that has been raised to a high energy level by pump lasers. At the far end of the linear transmission the steps are reversed. The optical receiver takes the light signal and converts it into the appropria...

This project seeks to link Asia to Europe via the Saudi Arabian desert. Telecom Egypt is not a consortium member, which suggests it will bypass Egypt to avoid transit fees and provide new network routing diversity. Frankly, little known is about the project. Key consortium members including center3, a Saudi Telecom subsidiary, the Cyprus incumbent, a Greek power company, and a Greek satellite company. The consortium was formed on May 31, 2022. In May 2023, center3 signed a supply contract for the project with ASN. A supply contract in force suggests the consortium has raised the $850 million required to complete the project.  I believe the high price tag reflects either a new route across the Saudi Arabian desert or a high fibre pair count. The project is bound to be controversial in Saudi Arabia because the terrestrial route traverses Jordan's Aqaba data center and reaches the Mediterranean Sea via Israel. Note that the Jordan label is much larger than the Israel label. This proba...

There are a large number of desperately poor African states below Senegal and above Cote d'Ivoire on the West African Coast that have access to only one or no submarine cables. These nations include Liberia, Sierra Leone, Guinea, Guinea-Bissau, and the Gambia. Landlocked countries that would benefit from more subsea capacity adjacent to these coastal states include Mali and Burkino Faso.  Right now their main bandwidth supplier is ACE, which lands in all the listed coastal states. ACE is ASN's problem child. The kid that is always getting into trouble. It has a reputation for outages and network disruptions. The cable landing station operators in general hold the cable hostage. In Sénégal Orange manages the facility, charges high cross connects fees, and hence has a quasi-monopoly on its capacity. Similar problems bedevil ACE cable landing stations in general. In some countries an ISP consortium manages the cable landings, but abuse still occurs. In Sierra Leone, the government...

Americans like to focus on the first short lived Trans-Atlantic cable, a project completed in 1858. But the first commercial and successful subsea communication cable connected Paris and London. The honors go to the startup English Channel Submarine Cable Company, which two engineer brothers, Jacob and John Watkins Brett, founded. Its first attempt in 1850 failed. There are several differing accounts. What these accounts have in common is that the cable had no protection. One colorful story is that the cable lasted 24 hours before a French fisherman cut the cable thinking it was a new type of seaweed. According to this account, the cable sent a telegraph message to Prince Louis Napoleon Bonaparte before the cable died. Other more reliable accounts suggest the cable never worked at all. But the second attempt in 1851 using armored cable was successful. Commercial telegraph service between London and Paris began November13, 1851. Landing points were near Calais and Dover. It was viewed a...

 ***100G; SMW5; Marseille/Singapore; $32.5K; 3 Year Term. ***100G; AAE1; Marseille/Singapore; $28.5K; 3 Year Term. Take It Or Leave It Offers. Don't even think of trying to negotiate. It's not that kind of market and you know it. 🙂

More details on the 16 fibre pair SMAP cable that will connect key Australian cities including Perth, Adelaide, Melbourne, and Sydney. Australia has traditionally been cursed by very high subsea capacity pricing. Right now there is a burst of construction on both land and at sea including Subco's SMAP, a new Google cable linking the continent to the US, Telstra's new 14,000 kilometer backbone, the publicly owned national backbone known as NBN, etc. SMAP is a 400 Tbps system. It is possible that it will be cheaper for ISPs to connect Australian cities by taking 100G or 400G waves on SMAP as opposed to terrestrial capacity or SMAP will be a protect path for terrestrial routes.  We are seeing a host of subsea cables that connect major cities in a single country. Other examples include the Confluence-1 network linking East Coast American cities and the Unitirreno project doing the same for Italy. It is an open question whether these cables will attract sufficient demand to be succe...

 Tallinn/Vilnius: 1650 Euros. Vilnius/Warsaw: 1650 Euros. Warsaw/Frankfurt: 1250 Euros. Just avoid those Sneaky Swedes ... Ride the Baltic Highway Express ...

This PTT-dominated consortium project is a 16 fibre pair cable connecting Asia's Pacific Rim to America. The Pacific is one of the regions where pricing is high enough that telecom carriers can get a respectable return on their investment. As a result telecom consortiums are still active unlike the Atlantic. The main trunk runs from Taiwan to the US with South Korean and Japanese branches. Total day one capacity is slightly over 192 Tbps. Chunghwa, SK Broadband, Softbank, and Verizon are consortium members. Unlike a traditional consortium where members receive lit capacity based on their share of total investment, each owner receives fibre pairs. Hence this is an open cable where only the wet plant and power feeding equipment is collectively owned and managed. Cable is scheduled to be RFS in 2H2028. The RFS date reflects a tight cable ship market.

***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...