一种折射率传感的双芯光纤设计

The Design of a Dual-core Fiber for Refractive Index Sensing

提出了一种新型折射率传感的双芯光纤,该型光纤横截面有两个纤芯且竖直对称分布,光纤中心引入一个小孔。采用全矢量有限元方法和传统的模式耦合理论分析了该双芯光纤的传感特性。基于该双芯光纤的两个纤芯之间模式耦合理论,研究结果表明该型折射率传感的双芯光纤传感器折射率传感范围为1-1.45,且灵敏度最高达到1028.5464nm/RIU。当宽带光入射到双芯光纤的一个纤芯时,通过检测可以在光纤输出端的另一纤芯上获得相应的光谱,其输出光谱随光纤中心小孔折射率变化呈类似正弦函数变化曲线。

A dual-core fiber （DCF） with two vertically and symmetrically distributed fiber cores and an air hole in the cross-section is proposed for refractive index （RI） sensing. Full-vector finite-element method and the conventional coupled-mode theory are used to investigate the properties of the proposed DCF. A DCF-based RI sensor with a measurement range from 1 to 1.45 and sensitivity up to 1028.5464 nm/RIU （refractive index unit） is achieved based on the mode coupling between two fiber cores of the DCF. The RI of the material medium in the central hole can be achieved by measuring the wavelength shift of the output spectrum with sine-function-like profile at one fiber core of the DCF, when the broadband light is injected into another fiber core.