Li Jie, Geng Mengmei, Sun Li-Peng, Fan Pengcheng, Liu Bo, Guan Bai-Ou
Opt Express. 2016 Apr 18;24(8):8547-54. doi: 10.1364/OE.24.008547.
We demonstrate a single taper-based all-solid photonic bandgap (AS-PBG) fiber modal interferometer that consists of a central tapered fiber region connected to the untapered via two abrupt transitions. Modal interference is given by superimposing the bandgap-guided fundamental core mode with a lower effective index and a specific index-guided cladding supermode with a higher effective index. A series of interferometers with taper diameter of 50μm ~60μm and device length of ~3mm are fabricated and studied in contrast to the conventional counterparts. The temperature coefficient of the interferometer is closely determined by the fraction of the cladding supermode energy localized within the index-raised regions of the fiber. The refractive index (RI) responsivities associated to fiber taper sizes are investigated. The measured maximal RI sensitivity is ~3512.36nm/RIU at the taper diameter of 50μm around RI = 1.423. This research gives a deep understanding to the modal-interferometric AS-PBG structure, which we believe to be valuable for the future application of the related device.
我们展示了一种基于单锥度的全固态光子带隙（AS-PBG）光纤模态干涉仪，它由一个中心锥形光纤区域组成，该区域通过两个突变过渡与未变细的部分相连。模态干涉是通过将具有较低有效折射率的带隙引导基模与具有较高有效折射率的特定折射率引导包层超模叠加来实现的。与传统同类产品相比，制作并研究了一系列锥度直径为50μm至60μm且器件长度约为3mm的干涉仪。干涉仪的温度系数由光纤折射率增加区域内局域的包层超模能量分数密切决定。研究了与光纤锥度尺寸相关的折射率（RI）响应特性。在RI = 1.423附近，锥度直径为50μm时测得的最大RI灵敏度约为3512.36nm/RIU。这项研究深入了解了模态干涉式AS-PBG结构，我们认为这对相关器件的未来应用具有重要价值。
