High-Sensitivity Fiber-Optic Temperature Sensing System Based on Optical Pulse Correlation and Time-Division Muliplexer Technique

摘要

A novel high-sensitivity fiber-optic temperature sensing system based on the optical pulse correlation principle is proposed. The optical pulse correlation state corresponding to the time drift in fiber-optic transmission lines is detected by a second harmonic generation (SHG) crystal. This sensing system is combined with 3- and 100-m-long monitoring fibers using a time-division multiplexer (TDM) combination technique. By using the linear trend-line method to combine the correlation values of short and long monitoring fibers, a high-temperature sensitivity of 0.001 ℃/mV and an approximatly 20 ℃ dynamic measurable range are successfully achieved.