Opt Lett. 2023 May 15;48(10):2531-2534. doi: 10.1364/OL.484658.
We report continuous measurements of the transmission spectrum of a fiber loop mirror interferometer composed of a Panda-type polarization-maintaining (PM) optical fiber during the diffusion of dihydrogen (H) gas into the fiber. Birefringence variation is measured through the wavelength shift of the interferometer spectrum when the PM fiber is inserted into a gas chamber with H concentration from 1.5 to 3.5 vol.% at 75 bar and 70°C. The measurements correlated with simulation results of H diffusion into the fiber lead to a birefringence variation of -4.25 × 10 per mol m of H concentration in the fiber, with a birefringence variation as low as -9.9×10 induced by 0.031 μmol m of H dissolved in the single-mode silica fiber (for 1.5 vol.%). These results highlight a modification of the strain distribution in the PM fiber, induced by H diffusion, leading to a variation of the birefringence that could deteriorate the performances of fiber devices or improve H gas sensors.
我们报告了在氢气（H）扩散到光纤中时，由熊猫型保偏（PM）光纤组成的光纤环镜干涉仪的传输光谱的连续测量结果。当 PM 光纤插入气体室中时，通过干涉仪光谱的波长移动测量双折射变化，H 浓度从 1.5 到 3.5 体积%，在 75 巴和 70°C 下。与光纤中 H 扩散的模拟结果相关的测量结果导致光纤中 H 浓度每摩尔 m 的双折射变化为-4.25×10，光纤中溶解的 0.031 μmol m 的 H 引起的双折射变化低至-9.9×10（对于 1.5 体积%）。这些结果突出了由 H 扩散引起的 PM 光纤中应变分布的变化，导致双折射的变化，这可能会恶化光纤器件的性能或改善 H 气体传感器。
