Patent ID: 7884997

Claim:
A laser system comprising: a master oscillator for generating a primary laser signal; a beam splitter array for splitting the primary laser signal into a sample reference signal and a plurality of secondary laser signals; an optical frequency shifter for shifting the frequency of the sample reference laser signal to provide a frequency-shifted reference beam; a beam expander for expanding the frequency-shifted reference beam to provide an expanded frequency-shifted reference beam; a plurality of amplifier arms that each receive a respective secondary laser signal of the plurality of secondary laser signals, each amplifier arm comprising a path length adjuster for adjusting a path length of the amplifier arm and an amplifier for amplifying the secondary laser signal to provide an amplified output signal; a beam sampler that interferes the light of the amplified output signal of the plurality of amplifier arms with the expanded frequency-shifted reference beam to provide a plurality of optical heterodyne detected (OHD) beat signals; a plurality of photodetectors that each receive a respective OHD beat signal to provide a plurality of OHD electrical beat signals, each OHD electrical beat signal having a maximum amplitude that corresponds to a minimum path length mismatch of a respective amplifier arm; and a path length controller responsive to the plurality of OHD electrical beat signals for providing a plurality of feedback signals to adjust the path length adjusters to control the path length of each of the plurality of amplifier arms to within a coherence length of the primary laser signal.