Influence and simulated correction of tip/tilt phase error on fiber laser coherent beam combination
倾斜相差对光纤激光相干合成的影响与模拟校正

Near-field models of coherent beam combination (CBC) with different beam channels and fill factors are employed, and the influences of tip/tilt phase errors on CBC are studied. The key device for tilt-error correction, named adaptive fiber optics collimator(AFOC), is introduced. A MOPA-configuration fiber laser CBC system compensating both piston and tip/tilt phase errors is designed. Then, the dynamic courses of tilt-error correction using stochastic parallel gradient descent (SPGD) algorithm in a seven-channel system are simulated, and the effects of CBC at different tilt-error amplitudes and frequencies are investigated. Experimental results show that the tilt-error should be corrected to improve CBC effects, and algorithm's control ability drops off when tilt-error amplitude and frequency increase. The results in this paper present a reference for multi-channel high power fiber laser CBC systems in real atmospheric environments.