Coherent beam combination of three two-tone fiber amplifiers using stochastic parallel gradient descent algorithm.
Multitone radiation is a promising technique to mitigate stimulated Brillouin scattering effects in narrow-linewidth fiber amplifiers. We demonstrate coherent beam combination of three two-tone fiber amplifiers using a stochastic parallel gradient descent (SPGD) algorithm. Phase control on the fiber amplifiers are performed by running the SPGD algorithm on a digital signal processor. The contrast of far-field intensity pattern of a coherently combined beam is more than 85%. Experimental results validate that a single-frequency seed laser is not indispensable for coherent beam combination in master oscillator power amplifier configuration.
Zhou
Pu
P
College of Opticelectric Science and Engineering, National University of Defense Technology, Changsha 410073, China.
Ma
Yanxing
Y
Wang
Xiaolin
X
Ma
Haotong
H
Xu
Xiaojun
X
Liu
Zejin
Z