基于MPLC提高空间光-单模光纤耦合效率技术研究

Research on MPLC-Based Technology to Improve the Coupling Efficiency of Spatial Optical-Single-Mode Fibers

在空间激光通信实际应用过程中,受到对准误差的影响,单模光纤耦合效率低,需要对其进行精确校正。在理想条件下,首先分析不存在对准误差及其他影响因素时平面波-单模光纤耦合效率及高斯光-单模光纤耦合效率模型,然后分别研究了光纤横向偏移和纵向偏移两种对准误差对单模光纤耦合效率的影响。在此基础上,提出了一种基于多平面光转换(MPLC)技术提高单模光纤耦合效率的方法,数值仿真了使用MPLC将平面波转化为高斯光前后及校正对准误差前后耦合效率的变化情况。仿真结果表明:使用MPLC将平面波转换为与高斯光高度相似的光束后,耦合效率会比平面波直接耦合进入单模光纤提高18.54%;使用MPLC分别校正横向偏移和纵向偏移后,耦合效率均提升至99%以上。该方法突破了空间光与单模光模式不匹配的限制,可以有效校正对准偏移误差,对于提高空间光到单模光纤的耦合效率具有一定的理论意义。

In the practical application of space laser communication,an alignment error will affect the coupling efficiency of singlemode fibers,which must be corrected accurately.Under ideal conditions,the plane wavesinglemode fiber coupling efficiency and Gaussian lightsinglemode fiber coupling efficiency models with no alignment errors or other influencing factors were first analyzed and compared.The effects of the coupling efficiency of a singlemode fiber with two alignment errors,lateral and longitudinal fiber offsets were studied.A method was proposed to improve the coupling efficiency of singlemode fibers based on MPLC technology.The change in the coupling efficiency before and after converting the plane wave into Gaussian light and correcting the alignment error using multiplane light conversion(MPLC)was simulated numerically.The simulation results showed that the plane wave was converted to a beam that is similar to Gaussian light by MPLC,and the coupling efficiency was 18.54%higher than the plane wave coupled directly to a singlemode fiber.The coupling efficiency was improved to more than 99%after correcting the transverse and longitudinal offsets by MPLC.This method breaks through the limitation of mismatch between spatial light and singlemode optical mode and can effectively correct the alignment deviation error.The method also has theoretical significance for improving the coupling efficiency of spatial light to singlemode optical fibers.