Patent ID: 8755649

Claim:
A method comprising: generating a seed-signal laser beam; propagating the seed-signal laser beam in a forward-traveling direction in a core of an input optical fiber; splitting the forward-traveling seed-signal laser beam from the core of the input optical fiber into a plurality of portions including a first portion having majority of the forward-traveling seed-signal laser beam and a second portion having a minority of the forward-traveling seed-signal laser beam; directing the first portion of the forward-traveling seed-signal laser beam into a core of a first output optical gain fiber and directing the second portion of the forward-traveling seed-signal laser beam into a core of a second output optical fiber; amplifying the first portion of the forward-traveling seed-signal laser beam in the first output optical gain fiber; directing at least a first portion of a backward-traveling laser beam from the core of the first output optical gain fiber into a third output optical fiber; and analyzing the second portion of the forward-traveling seed-signal laser beam and analyzing at least the first portion of the backward-traveling laser beam.