Patent ID: 7924894

Claim:
A laser system comprising: a plurality of laser sources each producing a respective beamlet to form a plurality of respective beamlets, one of said plurality of respective beamlets being definable as a reference beamlet, and all other beamlets of said plurality of respective beamlets being definable as non-reference beamlets via an array detector; a diffractive optical element (DOE) optically coupled to said laser sources for combining said plurality of respective beamlets into an output beam; each of said non-reference beamlets exhibiting a respective piston error characteristic, said piston error characteristics producing piston error artifacts in said output beam; a piston error controller adapted to measure said piston error artifacts in said output beam and produce a coded correction signal using a code generator related to said piston error characteristic of one of said non-reference beamlets; and a phase modulator interposed in said one of said non-reference beamlets for minimizing said piston error characteristic responsive to said correction signal.