一个新型的基于全光纤Mach-Zehnder干涉仪BOTDR系统

报道了新型的分布式传感测量布里渊光时域反射(BOTDR)系统.布里渊散射频移和强度均依赖于温度和应变,因此,BOTDR利用光纤中的自发布里渊散射作为测量信号可以实现分布式温度和应变测量.在BOTDR中,光源采用窄谱半导体激光器,并由声光调制器调制成脉冲光,经掺铒光纤放大器放大后,注入测试光纤以产生自发布里渊散射.利用双通Mach-Zehnder干涉仪分离光纤背向散射中的自发布里渊散射与瑞利散射信号,实现了自发布里渊散射的直接检测.实验结果表明基于全光纤Mach-Zehnder干涉仪BOTDR方案是可行的.

A Novel BOTDR System Based on All Fiber Mach-Zehnder Interferometer

A Brillouin optical-fiber time domain reflectometry (BOTDR) system for distributed sensing measurement was reported. Both Brillouin frequency shift and intensity depend on the temperature and strain,therefore, using spontaneous Brillouin scattering in optical fiber as the measurement signal, a BOTDR can measure the temperature and strain along the fiber. In BOTDR, a narrow line width LD was used as a light source. The light from LD was modulated into light pulses by an AOM and amplified by an EDFA to generate spontaneous Brillouin OTDR signal. A double-pass Mach-Zehnder interferometer was used to separate the spontaneous Brillouin scattering from Rayleigh scattering, thus a direct optical detection method was applied in the detection of spontaneous Brillouin scattering light. The experimental results showed that the configuration of the BOTDR based on all fiber Mach-Zehnder interferometer was feasible.