Design Of A High Resolution Temperature Measurement System Based On Optic Frequency-Modulated Continuous-Wave Technology

The intrinsic optical fiber Fabry-Pérot interferometer(FPI) temperature sensors are demodulated based on Spectrum(Optical Spectrum Analyzers and Broad Band Source),the temperature accuracy is limited by the Optical Spectrum Analyzers(OSA), is only 1 ℃.This paper proposes a high accuracy and low cost demodulation, which is based on frequency modulated continuous wave(FMCW) technology. FMCW technique has been used to demodulation extrinsic optical displacement and position sensor, this paper firstly apply it to the intrinsic optical fiber temperature sensors.Firstly,this paper explained the formation mechanism of the FMCW technique and application methods, then building a complete experimental system for experimental verification according to the theoretical analysis.Building the experimental system is the difficulty and emphasis in this paper, it involves the following important aspects:Sensor analysis and production,Laser selection and testing,High precision temperature control system,Photoelectric detector,Data analysis and processing.And then completed the temperature experiments using the builded system and using the traditional way.At last, by analyzing the experimental data we obtained the conclusion: the FPI sensor temperature precision is nearly 100 higher demodulated by the system based on FMCW technology than by the traditional way.