详细分析了由光纤光栅和萨尼亚克(Sagnac)环构成的透射滤波器的特性。给出了在均匀光纤光栅的情况下,该滤波器透过率的解析公式。结果表明该滤波器的透射光谱是余弦函数调制后的光纤光栅反射光谱。当光纤光栅是“强”耦合时,该滤波器可以构成多通带滤波器。而当光纤光栅为“弱”耦合时,该滤波器可以构成单通带滤波器。这些滤波器可应用于现代光纤通信系统中。

The transmission characteristics of the filter composed of a Sagnac loop and fiber Bragg gratings are studied in detail. The analytical results are given for the uniformed fiber grating. It was found that the transmission spectrum of the filter is the cosine function modulated reflection spectrum of the fiber grating. When the fiber grating is “strong” coupling, a multi-passband filter can be constructed. When the fiber grating is “weak” coupling, a single-passband filter can be constructed. These filters can be used in modern optical fiber communications.