Theoretical investigation of a dual-channel optical fibre surface plasmon resonance hydrogen sensor based on wavelength modulation

A theoretical investigation of a dual-channel optical fibre surface plasmon resonance (SPR) hydrogen sensor based on wavelength modulation is presented in this paper. The matrix method for the multilayer model is used to calculate the normalized output power. The effect of the thickness of each layer of two four-layer stacks on the characteristics of the output spectrum of the proposed sensor is discussed. The suitable thickness of each layer is used for the configuration of the proposed sensor. Simulation results demonstrate that two resonant wavelengths from two channels independently depend on the hydrogen concentrations in the respective channels, and there is a one-to-one relationship between the resonant wavelength and hydrogen concentration for each channel. The proposed sensor can achieve the simultaneous detection of hydrogen concentrations in two different areas by measuring the resonant wavelength of each channel.