Ultra-long distance (300km) fiber Bragg grating sensor system using hybrid EDF and Raman amplification

A novel tunable fiber ring laser configuration with combination of hybrid Raman amplification and erbium-doped fiber amplification (EDFA) is proposed for realizing ultra-long distance (300km) fiber Bragg grating (FBG) sensor system. The experimental results show that a 300 km transmission distance is achieved with an optical SNR of 4 dB, which is the longest FBG sensing distance, to the best of our knowledge.