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.
College of Opticelectric Science and Engineering, National University of Defense Technology, Changsha 410073, China.
Pu
P
Zhou
Yanxing
Y
Ma
Xiaolin
X
Wang
Haotong
H
Ma
Xiaojun
X
Xu
Zejin
Z
Liu