基于光栅螺旋扫描和SPGD算法的单模光纤耦合方法

发布时间：2018-12-13 03:23

【摘要】：自由空间光通信系统需要将空间光高效耦合到单模光纤中,但聚焦光斑与单模光纤间的初始对准误差和随机横向偏移会导致极大的耦合损耗。对空间光到单模光纤耦合的理论模型进行了阐述,并分析了横向偏移及随机抖动对耦合效率的影响。在此基础上,为了提高光纤耦合效率,提出了一种基于光栅螺旋扫描算法和随机并行梯度下降(SPGD)算法的耦合方案,并仿真分析了误差校正过程及其对耦合效率的改善情况。仿真结果表明:通过设定最佳扫描步长,光栅螺旋扫描算法能够有效地校正初始对准误差,校正成功概率高于99%;校正后的残余初始对准误差集中在0.5~6.5μm范围内,耦合效率得到初步改善;开启SPGD控制算法后,聚焦光斑与单模光纤间的随机横向偏移得到校正,耦合效率能够有效提升至0.81,接近无湍流情况下的理论极限。校正后,耦合效率得到显著提高。
[Abstract]:The free-space optical communication system needs to efficiently couple the space light into the single-mode fiber, but the initial alignment error and the random lateral deviation between the focusing spot and the single-mode optical fiber will lead to great coupling loss. The theoretical model of coupling between spatial light and single mode fiber is described, and the effects of lateral offset and random jitter on coupling efficiency are analyzed. On this basis, in order to improve the coupling efficiency of fiber, a coupling scheme based on raster spiral scanning algorithm and stochastic parallel gradient descent (SPGD) algorithm is proposed, and the error correction process and the improvement of coupling efficiency are simulated and analyzed. The simulation results show that the raster spiral scanning algorithm can effectively correct the initial alignment error by setting the optimal scanning step size, and the correction success probability is higher than 99. After correction, the residual initial alignment error is concentrated in the range of 0.5 渭 m and 6.5 渭 m, and the coupling efficiency is improved preliminarily. After the SPGD control algorithm is turned on, the random lateral migration between the focusing spot and the single-mode fiber is corrected, and the coupling efficiency can be effectively increased to 0.81, which is close to the theoretical limit in the case of no turbulence. After correction, the coupling efficiency is improved significantly.
【作者单位】：中国科学院自适应光学重点实验室;中国科学院光电技术研究所;中国科学院大学;
【基金】：国家自然科学基金(61308082) 中国科学院科技创新基金(YJ16K004)
【分类号】：TN929.1

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