双Sagnac环滤波器的传输特性分析和实验研究  

Analysis and Experimental Study on Transmission Characteristics of Double Sagnac Loop Filter

作　　者：崔文翔 周雪芳[1] 胡淼[1] 毕美华[1] 杨国伟[1] 李齐良[1] 王天枢[2] Cui Wenxiang;Zhou Xuefang;Hu Miao;Bi Meihua;Yang Guowei;Li Qiliang;Wang Tianshu(School of Communication Engineering,Hangzhou Dianzi University,Hangzhou,Zhejiang 310018,China;Institute of Space Optoelectronics Technology,Changchun University of Science and Technology,Changchun,Jilin 130022,China)

机构地区：[1]杭州电子科技大学通信工程学院,浙江杭州310018 [2]长春理工大学空间光电技术研究所,吉林长春130022

出　　处：《中国激光》2022年第4期111-118,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61705055);浙江省重点研发计划项目(2019C01G1121168);浙江省科技厅公益基础项目(LGG19F050001)。

摘　　要：利用传输矩阵理论,对一种双Sagnac环滤波器的传输特性进行了理论推导和仿真分析,该滤波器由两段不同长度的保偏光纤(PMF)并联构成。仿真结果表明:该滤波器具有偏振无关和通道间隔可调的特性。对双Saganc环滤波器的传输谱进行了实验测试,通过调节滤波器中的偏振控制器(PC),可以实现通道间隔的可调操作,调整入射光的偏振态并不会改变光谱形状,与理论分析得到的结论一致。最后,为了验证双Saganc环滤波器在激光器系统中的通道间隔可调特性,设计了一种基于四波混频(FWM)效应和双Sagnac环滤波器的通道间隔可调多波长掺铒光纤激光器。实验结果表明:该激光器可以输出通道间隔为0.9 nm或0.35 nm的多波长激光,这与仿真结果以及测量结果一致。Objective An optical fiber Sagnac loop has been widely used to manufacture optical fiber sensors and optical fiber Sagnac loop filters because of its excellent characteristics such as simple structure,low insertion loss,and low cost.However,the single Sagnac comb filter cannot meet the requirements of some practical laser systems due toits fixed channel spacing.Recently,some research groups have proposed multi-wavelength erbium-doped fiber lasers based on a double Sagnac loop filter,however the transmission characteristics of this filter have not been investigated,which restricts its application in the fields of multi-wavelength fiber lasers and optical fiber sensing.Therefore,in this study,the transmission characteristics of a double Sagnac loop filter constructed by two segments of polarizationmaintaining fiber(PMF)in parallel are analyzed and discussed.The measurement results of transmission characteristics are consistent with those obtained by theoretical analysis.Moreover,a channel-spacing tunable multiwavelength erbium-doped fiber laser utilizing a double Sagnac loop filter with the assistance of four wave mixing(FWM)effect is experimentally demonstrated.Therefore,it is significantly important to analyze and experimentally investigate the transmission characteristics of a double Sagnac loop filter,which is helpful for the design of future multi-wavelength fiber lasers.Methods In this study,the transmission function of a double Sagnac loop filter is first calculated in detail by the transmission matrix theory,and the incident light is assumed to be in an arbitrary polarization state.Then,the simulated transmission spectra are carried out by the Matlab software.The theoretical analysis and simulation results indicate that the double Sagnac loop filter has the polarization-independent characteristic and the tunable channel spacing.To demonstrate the transmission characteristics of the double Sagnac loop filter,the experimental apparatus for measuring the transmission spectra of the filter is designed.Note that

关 键 词：光纤光学 光滤波器 传输矩阵理论 双Sagnac环 通道间隔可调 偏振无关 

分 类 号：O436[机械工程—光学工程]