Experimental Demonstration of Adaptive Optics Correction of the External Aberrations for Distributed Fiber Laser Array

A novel method of pre-compensating the phase distortions outside the fiber laser array based on active integrated wavefront sensing is proposed and demonstrated experimentally. The scheme and the working principle are introduced. Pre-compensation experiment of the fiber laser array based on a 7-element adaptive fiber optics collimator (AFOC) array with filled factor of 0.875 is presented. Residual error RMS of $0.11~\mu \text{m}$ is obtained while sensing lower order aberrations of a glass plate is with initial RMS of $0.62~\mu \text{m}$ . Metric of far-field power-in-the-bucket (PIB) is improved about 3.5 times after the phase distortions are pre-compensated. This method could promote the transmission efficiency of the fiber laser array in atmosphere, without limits of array scale and transmission light delay. This method would be upgraded to correct the aberrations located in the whole optical link from laser source to the target in the future. Such method would highly promote the applications of fiber laser array based systems like free space laser communication.