Multiplexed fibre Fizeau interferometer and fibre Bragg grating sensor system for simultaneous measurement of quasi-static strain and temperature using discrete wavelet transform

摘要

We present a multiplexed fibre Fizeau interferometer (FFI) and fibre Bragg grating (FBG) sensor system for simultaneous measurement of quasi-static strain and temperature. A combined spatial-frequency and wavelength-division multiplexing scheme is employed to multiplex the FFI and FBG sensors. A demodulation technique based on the discrete wavelet transform with signal processing enhancements is used to determine the measurand-induced physical changes of the sensors. The noise associated with the sensor signal is reduced by the block-level-thresholding wavelet denoising method, which is applied via the demodulation technique. This sensor system yields a high accuracy and resolution, and low crosstalk. It is well suited for long-term quasi-static measurements, especially for the structural health monitoring of large-scale structures.