为了获得对温度变化不敏感和信道隔离度好的光滤波器，提出了一种基于高双折射光子晶体光纤的 Sagnac环级联滤波器。运用 Jones矩阵理论对二阶级联 Sagnac环滤波器进行了理论分析和数值仿真，可得级联滤波器中两段高双折射光子晶体光纤长度之比为 2:1时，透射谱的半峰全宽为 0.4 nm，仅为单个 Sagnac环滤波器的 1/3，有效提高了滤波器的信道隔离度。结果表明，该级联滤波器有着良好的滤波效果，且对温度变化不敏感，可应用于 50 GHz的密集波分复用系统。

In order to acquire temperature-insensitive optical filter which also has good channel isolation, a novel Sagnac loop cascaded . lter based on highly birefringent photonic crystal fiber (HiBi-PCF) is proposed. Theoretical analysis and numerical simulation are conducted to the two-order cascaded Sagnac loop filter with Jones matrix theory. When the length ratio of the two segments of HiBi-PCFs in cascaded filter is 2:1, the full-width at half-maximum (FWHM) of transmission spectrum is 0.4 nm, which is only 1/3 of that of the single Sagnac loop filter, so as to effectively improve the filter channel isolation degree. The results show that this kind of filter possesses a good filtering effect and is also insensitive to the temperature change, which can be applied to 50 GHz dense wavelength division multiplexing (DWDM) system.