Signal Demodulation for Surface Plasmon Resonance Tilted Fiber Bragg Grating Based on Root Sum Squared Method

There is an increasing interest in the use of surface plasmon resonance tilted fiber Bragg grating (SPR-TFBG) as a sensor for various chemical applications. Signal demodulation is an important process for extracting useful parameters from the unique optical spectra for an accurate measurement. In this work, we proposed a global-based estimator for SPR-TFBG based on a spectral subtraction approach. The estimator is generated based on the root sum squared (RSS) error of the spectral intensity difference between the tested spectrum and the reference spectrum. In the comparison with the other established methods, the proposed method has the lowest standard deviation, the maximum absolute deviation, the finest measurement resolution, and the fastest processing speed. Besides, the proposed method is immune to the interference of white noise in the transmission spectra and capable of producing a high-quality signal with the lowest noise level.