Patent ID: 8514485

Claim:
A fiber amplifier system comprising: a splitter splitting a feedback beam into a plurality of fiber beams; a plurality of fiber amplifiers each receiving and amplifying a fiber beam, said fiber amplifiers each including an output end; a tapered fiber bundle including an input end and an output end, said input end being coupled to the output end of all of the fiber amplifiers, said output end of the tapered fiber bundle being a combined fiber including a portion of all of the fiber amplifiers with fiber cores in a single fiber mass, said tapered fiber bundle outputting a combined output beam, wherein the tapered fiber bundle is formed and configured so that individual fiber modes propagating in each fiber amplifier coherently combine in the tapered fiber bundle into a single combined fiber mode in the combined output beam; an end cap optically coupled to the output end of the tapered fiber bundle, said end cap expanding the output beam from the tapered fiber bundle; a beam sampler for sampling a portion of the output beam from the end cap and providing a focused sample beam; and a single mode fiber receiving the focused sample beam from the beam sampler, said single mode fiber providing the feedback beam.