Coherent beam combination of three two-tone fiber amplifiers using stochastic parallel gradient descent algorithm

摘要

Multitone radiation is a promising technique to mitigate stimulated Brillouin scattering effects in narrow-nlinewidth fiber amplifiers. We demonstrate coherent beam combination of three two-tone fiber amplifiersnusing a stochastic parallel gradient descent (SPGD) algorithm. Phase control on the fiber amplifiers are per-nformed by running the SPGD algorithm on a digital signal processor. The contrast of far-field intensity pat-ntern of a coherently combined beam is more than 85%. Experimental results validate that a single-frequencynseed laser is not indispensable for coherent beam combination in master oscillator power amplifiernconfiguration. © 2009 Optical Society of America