研究了一种结构新颖、光谱特性可精确控制的Sagnac环滤波器,此滤波器通过在传统Sagnac环 中插入两段高双折射光纤和一个偏振控制器构成。利用等效光路和传输矩阵法理论研究了该滤波器的滤 波特性。研究结果表明:固定两段高双折射光纤参数,仅通过调整偏振控制器的状态,便可精确控 制Sagnac环滤波器的滤波光谱特性。将Sagnac环滤波器用于掺铒光纤(EDF)放大自发辐射(ASE)光 源的光谱平坦滤波,通过调节偏振控制器三个波片的倾斜角度,实验获得了光谱平坦的宽带ASE激光。

The precisely controlled spectral characteristics of a novel Sagnac loop filter was studied, which is structured by insertting two segments of high birefringence optical fiber and a fiber polarization controller into a conventional optical fiber Sagnac loop filter. The filtering characteristics of the filter was investigated theoretically by using the equivalent optical-path analysis and transfer matrix method. Results show that when the birefringence parameters of fiber are fixed, the spectral characteristics of the Sagnac loop filter can be precisely controlled by changing the polarization controller status. The Sagnac loop filter can be used to flat the spectra of erbium-doped fiber (EDF) amplified spontaneous emission (ASE) light source, and the broadband ASE laser with flat spectra is obtained in experiment by controlling the tilt angle of the three waveplates of polarization controller.