波分复用器件自聚焦透镜耦合系统的优化设计

Optimal design of gradient-index rod lens coupling system for wavelength-division multi/demultiplexers

利用光纤矩阵方法和高斯光学的耦合损耗理论 ,对波分复用器件的自聚焦透镜耦合系统进行了分析 ,得出了一种优化设计耦合系统的分析和计算方法 .结合计算结果的曲线 ,分析了耦合系统中透镜长度对耦合损耗的影响 。

The coupling system of gradient index rod lens (GRIN lens) for wavelength division multi/demultiplexier was analyzed by applying principles of ray matrix and coupling theory of Gaussian beam. An analytic method for optimal design and formulas to calculate coupling loss were developed. With the help of curves, the influence of parameters of coupling system on the coupling loss was analyzed. Coupling loss arose when the separation between the GRIN lens increased. Results showed that when input GRIN lens and output GRIN lens was equal to quarter pitch, the coupling loss was not the minimum. The influence of angular tilt of input single mode fiber on the GRIN lens was analyzed. A new method to reduce the coupling loss by adjusting the angular tilt was proposed.