Phase locking of a coherent array of 32 fiber lasers

An experiment of phase locking of 32 fiber lasers is reported. A coherent array of 32 fiber lasers is built and a high-speed high-precision phase controller is designed based on field programmable gate array(FPGA). When the stochastic parallel gradient descent (SPGD) algorithm is implemented by the phase controller, the phases of the fiber lasers are locked and the output power of the combined laser is enhanced by a factor of about 26.