无波前传感自适应光学技术及其在大气光通信中的应用

Analysis of Adaptive Optics Techniques without a Wave-Front Sensor and Its Application in Atmospheric Laser Communications

无波前传感自适应光学(AO)系统不依赖波前传感器可直接对系统性能进行优化。基于随机并行梯度下降(SPGD)算法,32单元变形镜,CCD成像器件等建立了无波前传感自适应光学系统实验平台。实验结果表明,参量选取合适时,系统对畸变波前具有较好的校正能力,但受限于较低的CCD采样频率,仅能校正静态或缓慢变化的像差。根据实验结果讨论了基于随机并行梯度下降控制算法的无波前传感自适应光学技术在大气光通信中的应用可能和应用方法,指出采用高速光电探测器件、高速数据处理及响应速度高的波前校正器与随机并行梯度下降算法相配合可用于补偿大气光通信中的大气湍流扰动。

The adaptive optics （AO） technique without a wave-front sensor can optimize the system performance directly, while being independent of wave-front sensor. Based on stochastic parallel gradient descent （SPGD） control algorithm, an adaptive optics test-bed without a wave-front sensor was built with a 32-element deformable mirror and a CCD. Experimental results show the test-bed can correct distorted wave-front successfully when parameters of the SPGD algorithm are appropriate for distorted wave-front. The test-bed only can correct static or slowly varied aberrations due to the slow sample frequency of CCD. Several implemental methods in atmospheric laser communications were discussed. SPGD control algorithm can be used to correct aberrations in atmospheric laser communication if being combined with high speed photodetector, high speed data processing and high response frequency wave-front corrector.