非对称级联型全光纤Fabry-Perot腔谱特性研究

为了进一步优化光纤光栅法布里-珀罗窄带滤波器的滤波性能，提出了基于光纤布拉格光栅的全光纤型非对称级联法布里-珀罗腔（FBG-FP）结构。通过传输矩阵方法，建立了数学仿真分析模型，推导出FBG-FP结构产生单峰谐振需满足的条件。对其传输特性进行了详尽的理论分析和模拟仿真，数值分析结果表明：通过对光纤布拉格光栅折射率调制深度以及谐振腔长等结构参量的优化组合，可以改善非对称双腔结构谐振光谱的通带平坦性和过渡带滚降特性；双腔FP器件可以得到更高的波长选择度，因此可用作信道化滤波与可调单频光纤激光器。

Theoretical Analysis of Transmission Characteristics of All-fiber Asymmetric Cascaded Fabry-Perot Cavity

To optimize the filtering of fiber Bragg grating based Fabry-Perot narrow-band filter furthermore, an all-fiber asym-metric optical filter of cascaded Fabry-Perot cavities with three fiber Bragg gratings is proposed and studied by using the transfer matrix method. On the base, the fiber Bragg grating Fabry-Perot cavity mathematical model is established. The propagation properties of the cascaded Fabry-Perot cavities are analyzed theoretically and simulated carefully. The indicates that the band-width of passband/stopband and the rolloff in transition band of asymmetric cascaded FBG-FP cavities are improved greatly, through selecting the refractive index modulation of fiber Bragg grating and the length of cavity appropriately. Also, because of cascaded Fabry-Perot device achieved single-frequency narrow linewidth output, higher wavelength selectivity, so the structure can be considered single mode linewidth filter for single-channel selection.