基于氧化锌涂层无芯光纤的氨气传感器研究  

Ammonia Gas Sensor Based on No-Core Fiber Coated with Zinc Oxide

作　　者：罗通 黄怿 邓传鲁 胡程勇 张小贝 王廷云 Luo Tong;Huang Yi;Deng Chuanlu;Hu Chengyong;Zhang Xiaobei;Wang Tingyun(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,School of Communication and Information Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学通信与信息工程学院,特种光纤与光接入网重点实验室,上海200444

出　　处：《中国激光》2023年第10期159-167,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(61735009,61875116,61875118,62022053);上海市自然科学基金(22ZR142300)。

摘　　要：为实现大气污染物中氨气(NH3)的快速、准确测量,本文提出了一种基于氧化锌(ZnO)涂层单模-无芯-单模(SNS)光纤结构的高灵敏度NH3传感器。该传感器利用的是ZnO膜层吸附NH3后自身折射率改变,进而导致无芯光纤干涉谱谐振波长发生变化的特性。通过建立NH3体积分数与谐振波长偏移量的关系,最终实现了NH3体积分数的测量。本文基于模式传输理论对ZnO涂层SNS传感器的光谱特性进行了仿真,仿真结果显示:当ZnO膜层的折射率从1.929变化至1.889时,60 nm和130 nm ZnO膜厚下SNS传感器的灵敏度分别为11.8 nm/RIU和28.6 nm/RIU。制备了ZnO膜厚分别为60 nm和130 nm的SNS传感器,其在NH3体积分数为0~42.0×10^(-6)环境下的灵敏度相差不大,这主要是由ZnO对NH3的吸附饱和引起的。进一步分析获得60 nm ZnO膜厚下SNS传感器的平均灵敏度为16.87×10^(6)pm,检测限为6.6×10^(-6),响应时间和恢复时间分别为70 s和90 s。随着温度由16.5℃升至56℃,该传感器对NH3的检测灵敏度从17.96×10^(6)pm降低至7.57×10^(6)pm,温度和时间对检测限的影响分别为0.0237×10^(-6)℃-1和0.026×10^(-6)d^(-1),该传感器具有较好的稳定性。Objective With the rapid development of global industry,air pollution is now a major problem.Ammonia(NH3)is a common toxic and harmful gas that is used in industrial production.Excessive intake of NH3 by the human body can lead to lung swelling and even death.Currently,NH3 detection is mainly conducted using electrochemical and optical methods.However,traditional electrochemical detection methods cannot realize real-time online monitoring.Optical detection can be classified into three types:absorption-spectrum,evanescent-wave,and refractive index variation.The absorption-spectrum type is easily affected by other gases in the same absorption band,whereas the evanescent-wave type has high requirements for achieving a precise tapering process.The refractive index variation type is based on variations in the refractive index of the sensitive film derived from NH3.In recent years,sensing technology that combines optical fiber sensors and functional films for realizing specific gas detection has become a research hotspot.Because zinc oxide(ZnO)has strong adsorption characteristics for NH3,the refractive index of ZnO varies.A no-core fiber is an optical waveguide with a unique structure,and its mode field can directly perceive changes in the external environment.Therefore,a new fiber gas sensor that combines a no-core fiber and ZnO film is studied in depth,which significantly promotes the rapid and accurate measurement of NH3 in atmospheric pollutants.Methods Based on mode transmission theory,the mode characteristics of a ZnO-coated no-core fiber and the sensing characteristics of a singlemode-no-core-singlemode(SNS)structure were analyzed using MATLAB software.First,the mode field distribution in the no-core fiber coated with ZnO was studied,and variations of the refractive index of the ZnO film with mode excitation coefficient and self-image length were discussed.Second,the relationship between the refractive index of the ZnO film and resonant wavelength of the interference spectrum was established.The NH3 sensing sys

关 键 词：传感器 无芯光纤 氧化锌 氨气测量 温度 

分 类 号：TN25[电子电信—物理电子学]