空芯光子晶体光纤与单模光纤耦合优化及在拉曼气体检测中的应用（英文）

Optimized coupling loss between single mode fiber and hollow-core photonic crystal fiber for Raman gas detection

分析了由菲涅尔反射、中心点偏移引起的耦合损耗.提出了一种新的方法——用T型金属管作为光子晶体光纤和单模光纤的连接器.计算了从单模光纤到光子晶体光纤方向以及从光子晶体光纤到单模光纤方向的最佳耦合距离,分别为15μm和25μm,实验证明了结论的可靠性.与传统的检测方法相比,采用光子晶体光纤的检测方法使得拉曼信号得到明显增强.以氮气为背景气,采用氧气肯定了光子晶体光纤同拉曼检测技术相结合后在气体检测方向的应用前景.

In this investigation,the coupling losses caused by Fresnel reflection,core misalignment between single mode fiber（ SMF） and HC-PCF are analyzed. A novel solution proposed from this research will reduce the coupling losses by using a T-type tube as a connector. Meanwhile,the theoretically calculated optimized gaps are at 15 μm in SMF-HCPCF direction and 25 μm in HCPCF-SMF direction. Thus,an experiment has been carried out,and the results of the practical gap in the above mentioned two directions have also been obtained. Furthermore,compared with detection by traditional methods,the proposed new detection method with PCF can remarkably enhance the Raman spectroscopy signal. Finally,the prospect of using the combination of HC-PCF and Raman spectroscopy in gas-cell detection has been demonstrated by using oxygen and nitrogen.