Author Affiliations
1School of Information and Control Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China2Xuzhou Key Laboratory of Artificial Intelligence and Big Data, Xuzhou, Jiangsu 221116, Chinashow less
Fig. 1. Cross-section of PCF and experimental principle diagram of the sensor. (a) Cross-section of PCF; (b) experimental principle diagram of the sensor
Fig. 2. Plots of the variations of β2, β4, and γ with methane concentrations. (a) Variation of β2; (b) variation of β4; (c) variation of γ
Fig. 3. Gas-sensitivity graph of Stokes and anti-Stokes spectra。(a) Phase mismatch plots for different methane concentrations; (b) DFWM gain plot of the Stokes and anti-Stokes signals near the pump wavelength; (c) peak wavelength of the gain signal for different methane concentrations; (d) relationship between wavelength shift and methane concentrations at a pump wavelength of 1080 nm
Fig. 4. Phase mismatch plots as well as Stokes and anti-Stokes signal gain plots obtained at different film thicknesses. (a) Phase mismatch plots; (b) Stokes and anti-Stokes signal gain plots
Fig. 5. Phase mismatch plots as well as Stokes and anti-Stokes signal gain plots obtained at different film thicknesses and methane concentrations. (a) Phase mismatch plots; (b) Stokes and anti-Stokes signal gain plots
Fig. 6. Phase mismatch plots as well as Stokes and anti-Stokes signal gain plots obtained at different pump wavelengths. (a) Phase mismatch plots; (b) Stokes and anti-Stokes signal gain plots
Fig. 7. Phase mismatch plots as well as Stokes and anti-Stokes signal gain plots obtained at different pump wavelengths and methane concentrations. (a) Phase mismatch plots; (b) Stokes and anti-Stokes signal gain plots
Fig. 8. Plots of the variation of β2, β4, γ, κ, DFWM gain plot of the Stokes and anti-Stokes spectra, peak movement curves and sensitivity fitting curves at a pump wavelength of 1079 nm. (a) β2; (b) β4; (c) γ; (d) κ; (e) Stokes and anti-Stokes spectra gains plots; (f) peak movement curves; (g) sensitivity fitting curves
Fig. 9. Movement of Stokes and Anti-Stokes Spectra when methane volume fraction changes from 0% to 0.05%
Λ /μm | d /μm | t /nm | λ /nm | L /m |
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3 | 1.25 | 260 | 1079 | 0.2 |
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Table 1. Structural parameters of the sensor
Type | Year | Sensitivity/ (nm/%) | Low detection limit | Ref. |
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PCF-LPG | 2017 | 1.078 | 1.8×10-3 | [21] | PCF-LPG | 2015 | 2.5 | 2×10-3 | [22] | Modal interference | 2016 | 0.51 | 1.6×10-3 | [19] | PC micro-cavity | 2015 | 1.67 | 7×10-4 | [23] | In this paper | 2019 | -4.87/2.83 | 5×10-4 /1.66×10-4 | |
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Table 2. Comparison of photonic crystal fiber sensor