基于光纤环形激光器和光放大的100km光纤布拉格光栅传感系统

100 km Fiber Bragg Grating Sensor System Based on Fiber Ring Laser and Optical Amplification

在基于掺铒光纤-拉曼混合放大的可调光纤环形激光器的光纤布拉格光栅(FBG)传感系统结构基础上,提出了延长传感距离的新方法。该方法以环形掺铒光纤激光器作为光源,采用双波长拉曼放大的方法对信号进行低噪声的双向放大,系统中间的两段掺铒光纤再利用剩余的抽运功率产生自发辐射光和放大传感信号,使得整个系统能够在超长的传感距离上获得很高的信噪比。实验表明使用一只40 mW的掺铒光纤放大(EDFA)抽运源、一只170 mW的拉曼抽运源和一只2 W的拉曼抽运源,可以使整个系统的传感距离达到100km,并且传感系统的光纤布拉格光栅反射信号均能获得超过57 dB的优良信噪比,从而实现在超长距离上的光纤布拉格光栅传感。

A novel method based on a tunable fiber ring laser configuration with Er-doped fiber Raman hybrid amplification is proposed for performance enhancement of long-distance in-fiber Bragg grating （FBG） sensor systems to achieve quasi-distributed measurement. Such a method employs a tunable Er-doped fiber ring laser as light source. Dual-wavelength Raman fiber amplification is adopted for achieving low-noise bidirectional amplification of FBG signals, and two sections of EDFs, arranged in the fiber link remotely, are used for generation of amplified spantaneous emission with residual pump power to illuminate remotely-located FBG sensors and amplification of sensing signals, which makes the whole sensor system capable of achieving quite high signal-noise-ratio along ultralong distance. Experimental results show that an excellent optical signal-noise-ratio of ～57dB has been achieved for a 100 km transmission distance with a low Er-doped fiber amplification pump power of～40 mW at wavelength of 980 nm, a low Raman pump power of ～ 170 mW at wavelength of 1455 nm and a Raman pump power of ～ 2 W at wavelength of 1480 nm,leading to FBG-based sensing along ultra-long distance.