Patent ID: 8111453

Claim:
A submarine optical link for communication between a first node and a second node in an optical communications system, wherein at least one of the first node or the second node is a submarine optical repeater, the submarine optical link comprising: a forward Raman pump at or proximate the first node; a forward optically pumped amplifier; a first fiber span interconnecting the forward Raman pump to the forward optically pumped amplifier such that the forward Raman pump injects forward optical power into the first fiber span thereby causing forward Raman amplification of an optical signal to occur within the first fiber span, and allowing a portion of a residual amount of the injected forward optical power from the forward Raman pump that remains after the forward Raman amplification to be used to power the forward optically pumped amplifier to further amplify the optical signal, wherein the on/off gain of the forward Raman amplification in the first fiber span is at least 1 dB; a backward Raman pump at or proximate the second node; a backward optically pumped amplifier; and a second fiber span interconnecting the backward Raman pump to the backward optically pumped amplifier such that the backward Raman pump injects backward optical power into the second fiber span thereby causing backward Raman amplification of the optical signal to occur within the second fiber span, and allowing a portion of a residual amount of the injected backward optical power from the backward Raman pump that remains after the backward Raman amplification to be used to power the backward optically pumped amplifier for amplification of the optical signal, wherein the on/off gain of the backward Raman amplification in the second fiber span is at least 5 dB.