Low-Cost Multi-Point Raman Fiber-Optic Temperature Sensors Enabled by CCD Cameras

This paper describes a low-cost fiber optical temperature sensor technology with wide operation temperature ranges and immune to complex electromagnetic environments. Using a low-cost passive frequency-double Q-switch YAG laser as the excitation source, multi-point fiber optical temperature sensors based on Raman backscattering are demonstrated. Using CCD cameras as optical sensors to detect both Stokes and Anti-Stokes backscattering signal, this paper shows that a 176-μW excitation optical power coupled into optical fiber is sufficient to perform accurate temperature measurement. The temperature sensors are calibrated against thermocouple sensors from 20 °C to 120 °C with temperature measurement mean square errors better than 2 °C. The technology described in this paper is particularly suitable for renewable energy applications such as battery monitoring.