双芯光子晶体光纤宽带定向耦合器研究

利用半矢量有限差分法设计了具有低折射率双芯的光子晶体光纤宽带定向耦合器,并数值计算了双芯光子晶体光纤的结构参量对耦合性能的影响.数值结果表明,通过优化选取光子晶体光纤包层结构参量和纤芯掺杂浓度,双芯光子晶体光纤耦合器可以实现宽带耦合.在1.22~1.65 μm 波长范围内其耦合长度稳定在26637 nm±235 nm范围内,耦合器设计成耦合比为50%和10%,分别实现了耦合比为（50±0.702）%和（10±0.664）%的良好特性.

Broadband Directional Coupler Based on Dual Core PCF

The depressed-index dual core PCF-based broadband directional coupler is designed by using semivectorial finite difference method.The influence of the structural parameters on the coupling characteristics in the dual core PCF was studied.The results show that the structural parameter of the cladding of the dual core PCF and the doping degree in the dual core region are optimised,the broadband coupling can be realised: in the wavelength range of 1.22~1.65 μm,the value of the coupling length is stabilized at 26 637 nm±235 nm and when the couplers are designed as two kinds of couple with coupling ratio of 50% and 10%,the coupling ratios of（50±0.702）% and（10±0.664）% are realized,respectively.