长周期光纤光栅导模与包层模的耦合分析

Analysis of Guided to Cladding Mode Coupling by Long Period Fiber Gratings

在对包层模进行远离截止近似下，利用耦合模理论分析了长周期光纤光栅中导模与包层模的耦合，并与短周期光纤光栅进行了比较，指出长周期光纤光栅的工作特性可由它的相位匹配条件来说明．计算结果与实验现象相符．

Considering the cladding modes as far from cut off, the intermodal coupling between guided and cladding modes by long period fiber gratings is analysed using coupled modes theory, and compared with that of short period fiber gratings. It is pointed out that the properties of long period fiber grating are related to its phase matching condition. Computation results show good consistent with experiments.