Coherent beam combination of pulse fiber amplifiers in 100ns-pulse regime

Coherent beam combining (CBC) in pulse regime is challenging because phase variation through gain depletion or nonlinear effects can be expected inside the pulses, usually very fast compared to the CBC phase-lock controller bandwidth. CBC by frequency-tagging is a well-known technique used in CW coherent beam combination of fiber amplifiers in a master-oscillator power-fiber-amplifier (MOPFA) configuration but is not directly applicable to the case of CBC of pulsed MOPFAs. In this communication we report on the demonstration of the CBC of two fiber amplifiers in 100ns-pulse regime with a frequency-tagging technique adapted to the pulse regime by introducing a CW signal leak [1] between the pulses.