基于纤芯失配型马赫曾德尔光纤折射率和温度同时测量传感器的研究  

Study of Fiber Sensor for Simultaneous Measurement of Refractive and Temperature Based on a Core-Mismatch Mach-Zehnder Interferometer

作　　者：傅海威[1] 闫旭[1] 李辉栋[1] 邵敏[1] 赵娜[1] 刘钦朋[1] 高宏[1] 贾振安[1] 乔学光[2] 

机构地区：[1]西安石油大学理学院光电油气测井与检测教育部重点实验室,陕西西安710065 [2]西北大学物理系,陕西西安710069

出　　处：《光学学报》2014年第11期58-63,共6页Acta Optica Sinica

基　　金：国家自然科学基金(61275088;61077060);国家863计划(2009AA06Z203)

摘　　要：设计和制作了一种基于单模-多模-细芯-单模光纤马赫-曾德尔（Mach—Zehnder）干涉仪结构，可同时测量折射率和温度的传感器。该传感器中，多模光纤和细芯-单模熔接点充当光耦合器。导入光纤中传输的光经多模光纤后在细芯光纤的纤芯和包层中激发出纤芯模和包层模，不同模式光在细芯光纤中传输时将产生光程差，再经细芯-单模熔接点耦合成为导出光纤的纤芯模而干涉。传感器透射光谱随着环境折射率和温度的变化发生漂移，通过监测不同级次的干涉谷可实现折射率和温度的同时测量。通过对传感器的透射光谱进行傅里叶变换分析可知该透射光谱主要由LP01模和LP15模干涉形成。该传感器透射光谱中1535nm附近干涉谷的折射率和温度响应灵敏度的理论值分别为-55．90nm／RIU和0．0501nm／℃（其中RIU为折射率单位）；1545nm附近干涉谷的折射率和温度响应灵敏度的理论值分别为-56．26nm／RIu和0．0505nm／℃。在折射率和温度的变化范围分别为1．3449-1．3972和20℃-90℃的环境中对传感器的响应特性进行实验研究，结果表明：透射光谱中1535nm附近干涉谷的折射率和温度响应灵敏度分别为-53．03nm／RIU和0．0465nm／℃；1545nm附近干涉谷的折射率和温度响应灵敏度分别为-54．24nm／RIU和0．0542nm／℃。理论分析与实验结果相一致。该传感器在生物医学领域有较好的应用前景。A fiber-optic Mach-Zehnder interferometer （MZI） based on single-mode -multimode-thin-core-single-mode fiber structure is proposed and demonstrated for measuring refractive index and temperature simultaneously. The multimode fiber （MMF） and the thin core fiber-single mode fiber （TCF-SMF） spliced point serves as mode coupler. When the light is launched into the MMF through the lead-in SMF, at the MMF-TCF spliced point, the core mode and cladding modes are excited and propagate in the core and cladding region of the TCF respectively. The optical path difference can be produced between different modes propagating within the TCF. Then, at the TCF-SMF spliced point, the excited cladding modes coupled back into the core of lead-out SMF interfere with the TCF core mode. When the surrounding refractive index （SRI） and temperature change, the transmission spectrum of the sensor shifts. On this basis, the simultaneous measurement of SRI and temperature can be completed by monitoring the dipswith different interference orders. The intermodal interference mainly occurs between the core mode LP01 and the cladding mode LP16 based on a fast Fourier transformation analysis for the transmission spectrum of the sensor. The sensitivities of the sensor response to the change of SRI and temperature are theoretically achieved. The SRI and temperature theoretical sensitivities of the interference dips at 1535 nm and 1545 nm are -55.90 nm/RIU, 0. 0501 nm/℃, and --56.26 nm/RIU, 0. 0505 nm/℃, respectively, where RIU is refractive index unit. The responses of the sensor are experimentally studied at the SRI range from 1. 3449 to 1. 3972 and temperature range from 20 ℃ to 90 ℃, and the sensitivities - 53. 03 nm/RIU, 0. 0465 nm/℃ and - 54. 24 nm/RIU, 0. 0542 nm/℃ for the two selected interference orders. The theoretical analysis of the sensor is in good agreement with that obtained in the experiment. This kind of sensor can offer attractive applications in biomedical sensing.

关 键 词：光纤光学 光纤马赫-曾德尔干涉仪 折射率和温度测量 纤芯失配 

分 类 号：TN253[电子电信—物理电子学]