All-fiber integrated high power coherent beam combination

A fiber amplifier system comprising:

• a master oscillator generating a signal beam;
• a splitter splitting the signal beam into a plurality of fiber beams;
• a plurality of phase modulators each receiving one of the fiber beams, said phase modulators providing phase modulation;
• a plurality of polarization controllers each receiving one of the fiber beams, said polarization controllers providing polarization orientation control;
• a plurality of fiber amplifiers each receiving a fiber beam after the phase modulator and polarization controller, said fiber amplifiers amplifying the 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 portions of all of the fiber amplifiers with fiber cores in a single fiber mass, said tapered fiber bundle outputting a 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 sample beam;
• a polarization detector detecting the polarization in the fiber beams in the sample beam and providing polarization error measurement signals;
• a synchronous polarization processor receiving the polarization error measurement signals and controlling the polarization controllers to control the orientation of the polarization of the fiber beams in the fiber amplifiers in response to the polarization measurement signals;
• and
• a collimating and magnifying telescope receiving the output beam from the end cap before the beam sampler, said collimating and magnifying telescope expanding and collimating the output beam.