Raman amplifier-based long-distance temperature/strain sensing system incorporating a combined sensing probe of an FBG and an EFG recyling residual Raman pump

Abstract

A novel, Raman amplifier-based long-distance sensing system using a combined sensing probe of an erbium-doped fiber (EDF) and a fiber Bragg grating is proposed for simultaneous measurement of temperature and strain. By recycling residual Raman pump power for generation of amplified spontaneous emission in the EDF after distributed Raman amplification in the transmission fiber, the overall system configuration was significantly simplified without requiring any additional broadband light source. A remote sensing operation of simultaneous temperature and strain measurement is obtained at a location of 50 km. High quality of sensing signals with a ~ 11 dB signal-to-noise ratio (SNR) is readily achieved even after the 50 km transmission with distributed Raman amplification.