Subsea Cable Beach Landing Infrastructure

Here's a very informative diagram of subsea cable landing infrastructure. Thanks to Nilesh N. The segment from the beach manhole to the cable landing station is called the front haul. From the beach manhole to the cable buried offshore is called the shore end. The ideal way to land a cable is to install a big pipe called a bore using directional horizontal drilling. The subsea cable goes through the bore pipe to a beach manhole where it is spliced to standard terrestrial fibre, usually G.652d or G.657a. Note it is possible to create a fibre ring between the manhole and the CLS for greater resiliency. All it requires is a cable splitter. 

Note that diagram places the back up generators in the basement. Not a good idea in a tsunami or hurricane zone subject to flooding. The Japanese nuclear accident happened because a tsunami flooded the reactor's basement where all the backup generators were located. No back up power for cooling led to the meltdown. So the earthquake destroyed the power lines to the reactor and also triggered the tsunami, which killed the back up power. Ideally, the CLS should be connected to two separate power grids, a rarity despite the gradual deregulation of power grids. 

It is also worth noting that the submarine line termination equipment, which includes the optical equipment, is typically no longer in the CLS. Instead, it is placed at a carrier neutral data center for interconnection and wholesale sales. The CLS has been downgraded in most new projects to a power hut, often a prefabricated, modular design. Bharti's 2Africa CLS in DRC is a prefabricated, modular system. The overall trend in subsea architecture is more flexible design in order to speed deployment and reduce costs. Most clients do not want to interconnect at the cable landing station. So it makes no sense to place the SLTEs in that facility. Instead, optical amplifiers can be used to boost the signal and carry it to a carrier neutral data center like Slough Equinix, LS1 or SG3 in Singapore.