Multi-span optical communications link having remote optically pumped amplifier

Abstract

A remote optically pumped amplifier in a multi-span optical communications link. A backwards Raman pump module performs backwards Raman amplification in an optical communications span that contains the remote optically pumped amplifier. A residual amount of backwards Raman pump power is then used to power the remote optically pumped amplifier. The remote optically pumped amplifier may be located 40 to 120 kilometers in optical distance from the backwards Raman pump module such that at least three milliwatts of residual Raman pump power is received by the remote optically pumped amplifier. The Raman pump module may be a multi-pump Raman pump module. A controller controls pump power provided by at least one of the pumps of the backwards Raman pump module, so as to at least partially compensate for optical signal strength versus wavelength variation introduced by the remote optically pumped amplifier and the backwards Raman pump module.

1 . An optical communications link comprising:
 a plurality of optical communications spans comprising:   a first communications span comprising a backwards Raman pump module, the first communications span comprising a remote optically pumped amplifier positioned from 40 to 120 kilometers in optical distance from the backwards Raman pump module and receiving at least three milliwatts of backwards Raman pump power from first backwards Raman pump module; and   a second communications span.   
     
     
         2 .- 15 . (canceled)