D-Shaped Tellurite Photonic Crystal Fiber Hydrogen and Methane Sensor Based on Four-Wave Mixing With SPR Effect

Abstract

A new D-shaped tellurite photonic crystal fiber sensor based on the four-wave mixing (FWM) effect with the surface plasmon resonance (SPR) effect is designed and optimized. The substrate of the D-shaped photonic crystal fiber (D-PCF) is tellurite glass, and the polished surface is plated with the gold film and hydrogen gas-sensitive film. An air hole of the inner cladding, which is plated with the gold film and methane gas-sensitive film, is selected as the second sensing channel to simultaneously measure the concentration of hydrogen and methane. Based on the four-wave mixing, the wavelength shifts of the Stokes and anti-Stokes spectra resulting from the variation of the gas concentration can be used to accurately detect the concentrations of methane and hydrogen. Meanwhile, it is found that the SPR effect can increase the wavelength shifts, which means the sensitivity of methane and hydrogen augment. After parameter optimization, the maximum sensitivities of methane and hydrogen are 4.03 nm/% and −14.19 nm/%, respectively. Both the linearities are up to 99.9%. The resolution of methane is 1.25×10−2% and hydrogen is 7.14×10−3%. Moreover, the fiber length of this sensor is only 20 mm, which is conducive to the construction of a compact or ultra-compact embedded FWM fiber sensor.

Highly sensitive methane gas sensor based on Au/UVCFS films coated D-shaped photonic crystal fiber

“…The reason for the above phenomenon was that the cladding hole had a great binding effect on the core energy and prevented the coupling between the core mode and the metal film. 1.99 nm/% 0 % -3.5% SPR [30] 4.03 nm/% 0 % -3.5% LPFG [19] 2.5 nm/% 0 % -3.5% Intermodal interference [21] 0.514 nm/% 0 % -3.5% Sagnac interference [32] 36.64 nm/% 0 % -3.5% SPR (this work) 9.88 nm/% 0 % -3.5%…”

“…The loss peak shifted to longer wavelength with the increase of gas sensing film thickness. The reason for the above phenomenon was that when the methane sensing membrane interacted with methane molecules, the dielectric constant of the methane sensing membrane changed, causing the resonance angle to shift [30]. Figure 8 showed the linear fitting of sensitivity under different methane gas sensing film thicknesses from 0%-3.5% methane concentration.…”

“…The sensing performances of the proposed SPR optical fiber methane sensor are compared with some reported optical fiber methane sensors, as shown in table 2. In reference [11,30] these sensors were based on SPR. Although they can measure two gases, their sensitivity was not high.…”

A sensitive methane gas sensor based on sagnac interferometer with a cryptophane-A film-coated birefringent photonic crystal fiber : design and FEM simulation

“…The comparison of these sensing performances is presented in table 1. In [27,30] these sensors are based on the SPR principle, which allows for the simultaneous measurement of two gases. Their advantage lies in their ability to detect multiple gases, but their sensitivity is relatively low.…”

A Review of Hydrogen Sensors for ECLSS: Fundamentals, Recent Advances, and Challenges

“…According to the principle, hydrogen sensors can be divided into catalyst combustion type [7][8][9], heat conduction type [10][11][12], semiconductor type [13][14][15], fiber-optic type [16][17][18], etc. Currently, hydrogen sensors of the heat conduction principle are used for hydrogen concentration detection in the electrolytic oxygen generation system of the space station, and hydrogen sensors of the catalyst combustion principle are used for hydrogen concentration detection in the space station environment.…”