7. Submarine links without repeaters

Submarine links without repeaters offer the following advantages:

• no high-voltage power supply in the terminal;

• no risk of a repeater breaking down and requiring a cable ship to repair it;

• the possibility of using cables containing up to 48 fiber pairs.

The aim is to be able to transmit the signal over the greatest possible distance without placing an active device (requiring a power supply) underwater.

For this purpose, the optical fiber used is pure silica core fiber (PSCF), which has the advantage of offering very low attenuation: typically 0.17 dB/km.

Secondly, there are various amplification techniques to increase the propagation distance. Three types of configuration are described in...