Coherent beam combining of fiber lasers using a CDMA-based single-frequency dithering technique

Abstract

Coherent beam combination (CBC) is a promising method to obtain high-power and high-brightness laser output. In this paper, we present a novel single-frequency dithering technique based on code division multiple access (CDMA). By using orthogonal phase control signals, the number of channels can be increased and the phase control speed in the coherent beam combination system can be boosted. The design method and coding expression of orthogonal signals, as well as the relevant simulations and experiments of the designed signals, have been demonstrated. In the experiment, we design four orthogonal signals and realize the phase locking of five channels. When the phase control system is in the closed loop, the residual phase error is less than λ/30 and the phase control speed of the CBC system is increased to nearly eleven times compared with that of the single-frequency dithering technique.