Method for amplifying an optical seed beam

A fiber laser amplifier system comprising:

• at least one beam source providing an optical seed beam at a certain center wavelength;
• at least one frequency modulation (FM) electro-optic modulator (EOM) responsive to the seed beam and a first RF drive signal, said FM EOM frequency modulating the seed beam using the first drive signal so as to broaden a spectral linewidth of the seed beam to a carrier spectral band;
• at least one amplitude modulation (AM) EOM responsive to the seed beam and a second RF drive signal, said AM EOM amplitude modulating the seed beam using the second drive signal so as to provide an amplitude modulated seed beam that is synchronized with the frequency modulated seed beam;
• at least one non-linear fiber amplifier receiving the AM and FM modulated seed beam and a pump power beam, said at least one amplifier amplifying the seed beam using the pump power beam to provide an output beam where most of the beam power resides in the carrier spectral band;
• a first beam sampler sampling off a first sample beam from the output beam;
• a filter receiving the first sample beam and filtering out the carrier spectral band from the first sample beam;
• a first detector for detecting beam power of the filtered sample beam and providing a first beam power signal;
• and
• a controller receiving the first beam power signal, said controller controlling one or more of the first drive signal, the second drive signal and the pump power beam to change the FM modulation depth, AM modulation depth and/or pump beam power in a manner that reduces the beam power of the filtered sample beam.