Photonic bandgap fiber-based gas sensor with high sensitivity and high birefringence

摘要

Abstract An ultra-sensitive gas sensor is proposed based on a hollow-core photonic bandgap fiber (HC-PBF), with high birefringence and acceptable confinement loss. The structural parameters of the HC-PBF were specifically selected so that the gas absorption lines that can be detected with this structure correspond to the bandgap wavelength range. Significant relative sensitivity and low confinement loss were obtained by considering an accurate core radius. High birefringence improved the stability and accuracy of the proposed structure against minor changes in the optical mode polarization. The symmetry of the fiber structure was modified in order to improve birefringence. To alter the symmetry of the proposed structure, the radius of the air holes was changed and two elliptical air holes were used. According to numerical analysis, relative sensitivity of 96.7, confinement loss of 0.11 dBmdocumentclass12pt{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$frac{{{text{dB}}}}{{text{m}}}$$end{document}, and birefringence of 8.76×10-3documentclass12pt{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$$8.76 times 10^{ - 3}$$end{document} were achieved.