title: Active phasing a nine-element 1.14 kW all-fiber two-tone MOPA array using SPGD algorithm.
abstract: We demonstrated active phase locking a nine-element 1.1 kW all-fiber master-oscillator power amplifier (MOPA) array using the stochastic parallel gradient descent (SPGD) blind optimization algorithm. Two spectrally combined single-frequency seed lasers, which provide potential ability to suppress the stimulated Brillouin scattering effect, are employed as a master oscillator for the nine MOPA channels. The nine laser beams are tiled side by side into a 3×3 laser array with a fill factor of 40% in the near field. When the SPGD controller is enabled, the metric function is increased 4.1 times, and a visibility more than 90% of the interference pattern at the receiving plane is obtained. The computed phase residual error is less than λ/15, despite the phase fluctuation of each channel.
authors.affiliation: College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha, 410073, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Pu
authors.initials: P
authors.lastname: Zhou
authors.forename: Yanxing
authors.initials: Y
authors.lastname: Ma
authors.forename: Jingyong
authors.initials: J
authors.lastname: Leng
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Xu
authors.forename: Zejin
authors.initials: Z
authors.lastname: Liu