Distributed temperature sensing with erbium-doped fiber amplifiers

The experimental verification of a novel fiber-optic sensor which performs distributed measurement of temperature by using a distributed erbium-doped fiber amplifier (EDFA) is presented. The sensor configuration is similar to that of a conventional optical time-domain reflectometer and detects the Rayleigh backscattered portion of a pulsed optical signal which is amplified by the EDFA, along with the backward amplified spontaneous emission (ASE) generated by the EDFA. The sensor utilizes the temperature dependence of the gain in an EDFA. The amplification provided by the erbium-doped fiber, which is pumped at 1.48 μm, significantly increases the magnitude of the optical signal reaching the receiver, thus leading to a simplified configuration and a potentially superior performance as compared to other types of distributed fiber-optic temperature sensors