A novel tunable fiber ring laser configuration with a combination of Raman amplification and erbium-doped fiber amplification (EDFA) is proposed for realizing high signal-to-noise ratio (SNR), ultra-long distance (300 km) fiber Bragg grating (FBG) sensor systems. The hybrid Raman-EDF amplification configuration can enhance the optical SNR of FBG sensor signals significantly, so the optical power reflected by the fiber Bragg grating can be compensated. A good optical SNR of 15 dB is achieved for a 275 km transmission distance, which is the best performance to our knowledge, and about 4 dB at 300 km. In the static strain experiments with fiber lengths of 100,200,250,300 km, the linearity is greater than 0.999. This system can be widely used in the ultra-long-distance sensing applications such as railways, oil(gas) pipelines and coastline.%提出了基于可调激光器和声光脉冲调制的光纤布拉格光栅(FBG)传感系统,同时利用掺铒光纤放大器(EDFA)和拉曼放大相结合的放大方案大幅度提高了光纤布拉格光栅传感系统的传输距离,达到了300 km的超长距离传感.该系统通过前端的EDFA和末端的拉曼泵浦光源来补偿光纤布拉格光栅反射的光功率.系统在低于275 km长度时获得了大于15dB的优良信噪比；在300 km处获得了4dB的信噪比,以及明显的反射信号.系统在100,200,250,300 km处的静态应变实验中,线性度均达到了0.999以上.系统可望在铁道、输油(气)管道、海岸线等的超长距离遥测中得到广泛应用.
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