论文部分内容阅读
给出了镀膜长周期光纤光栅芯层模式和包层模式耦合的耦合系数的详细表达式,应用此表达式对镀膜长周期光纤光栅的耦合系数的特性进行了较为详细的研究。研究发现:1)同次模式的耦合系数随薄膜厚度变化而变化,在某些厚度下,奇次模式耦合的耦合系数与偶次模式耦合的耦合系数几乎相等;2)在某些厚度处,交流耦合系数会有跳变发生;3)交流耦合系数随环境折射率的变化而变化,并且当环境折射率靠近光纤包层折射率时交流耦合系数会有急剧跳变发生。
The detailed expression of the coupling coefficient between the coated long-period fiber grating core mode and the cladding mode coupling is given. By using this expression, the coupling coefficient of the coated long-period fiber grating is studied in detail. The results show that: 1) the coupling coefficient of the same mode changes with the thickness of the film; at some thicknesses, the coupling coefficient of odd-mode coupling is nearly equal to the coupling coefficient of even-mode coupling; 2) At some thicknesses, AC coupling coefficient will jump; 3) AC coupling coefficient changes with the change of environmental refractive index, and when the environmental refractive index close to the refractive index of the fiber cladding AC coupling coefficient will have a sharp jump occurs.