利用激光多纵模拍频频率与谐振腔色散系数的关系实现光纤的色散测量.测量系统采用可调光纤Fabry-Perot滤波器与光环行器构成窄带波长可调反射镜, 作为光纤激光器的后腔镜, 以光纤Sagnac干涉器作为前腔镜.将待测光纤置于谐振腔内, 用频谱分析仪测量激光器拍频频率随激光输出波长的变化, 得到待测光纤的色散系数.用该系统分别测量了色散补偿光纤和标准单模光纤的色散系数, 实验结果表明该方法能够满足通信光纤的色散测量要求.该系统测量速度快、成本低、结构简单, 具有良好的应用前景.

The dispersion measurement of optical fiber is realized by utilizing the relationship between the multi-longitudinal mode beat frequency of the laser and dispersion coefficient of resonant cavity. A narrow band and wavelength tunable reflector is used as the rear-cavity mirror of the fiber laser in the proposed system, which is based on the combination of the fiber Fabery-Perot tunable filter and the optical fiber circulator. The Sagnac interferometer is used as the front-cavity mirror. The tested optical fiber is inserted in the resonator. The beat frequency of the fiber laser is measured by the spectrum analyzer, which is changed with the output wavelength of laser, and then the dispersion coefficient of the sample is obtained. The dispersion coefficient of dispersion compensation fiber and standard single mode fiber are measured respectively. The experimental results indicate that the measurement accuracy of the proposed system can meet the requirements of the communication optical fiber measurement. The proposed method has the advantages of high measurement speed, low cost, simple structure and good application prospect.