Analysis of Interference Spectrum of Separated Long-Period Fiber Grating Pairs and Its Applications
级联长周期光纤光栅对的干涉谱分析及其在多信道滤波器中的应用

The interference transmission spectrum of cascaded long-period fiber gratings, which is inserted a section of standard fiber, is investigated. Based on the design of key aspects, the particle swarm optimization (PSO) algorithm is used to design a flattened broadband transmission spectrum with transmission loss of nearly 50%. By cascading two such identical long period fiber gratings, a useful tunable multi-channel isolation filter is designed. The influence of polarization of the inserted fiber on the interference spectrum is discussed.