摘要
提出一种基于无芯-多模-无芯光纤(NMN)结构的硫化氢(H2S)气体传感器。该传感器将两个无芯光纤(NCF)熔接在多模光纤(MMF)的两端,构建NMN的结构。光从单模光纤(SMF)进入NCF中激发出不同高阶模式,进入MMF中时,激发出的高阶模与基模分别在MMF的包层和纤芯中传输从而产生相位差,形成模式干涉。同时,对不同长度NCF和MMF的传输特性进行了优化。采用浸渍提拉法在NCF的外表面形成二氧化钛薄膜,利用薄膜对H2S气体的吸附,实现对H2S的快速响应。随着H2S浓度的增加,干涉谱出现红移,在H2S气体体积分数为0~3×10^-5的范围内,得到了7.36 pm/10^-6的灵敏度和良好的线性度。此外,二氧化钛对H2S具有良好的选择性,响应和恢复时间分别约为50 s和65 s。该传感器具有结构简单、灵敏度高、制造方便等优点,在低浓度H2S气体的安全监测领域有潜在的应用价值。
We present a hydrogen sulfide(H2S) gas sensor based on a no-core-multimode-no-core(NMN) fiber structure. The sensor is fabricated by using two no-core fibers(NCF) which are spliced at both the ends of a multimode fiber(MMF), and the NMN structure is constructed. Different high-order modes can be excited when light travels from a single-mode fiber(SMF) to NCF. When light enters MMF, the high-order modes and fundamental mode transmit in the cladding and core of MMF, respectively, resulting in phase difference and mode interference. Simultaneously, the transmission characteristics of NCF and MMF having different lengths are optimized. The outside surface of NCF is coated with a thin titanium dioxide film by the dip-coating method;thus, a rapid response to H2S gas can be achieved when the film absorbs the gas. With an increase in the H2S concentration, the interference spectra denote a red shift. A sensitivity of 7.36 pm/10^-6 and good linear relation are obtained in the H2S volume fraction range of 0-3×10^-5. In addition, titanium dioxide exhibits good selectivity to H2S, and the response and recovery time of the sensor are approximately 50 s and 65 s. The sensor has advantages of simple structure, high sensitivity, and easy manufacturability, and it can be applied in the field of safety monitoring of the low-concentration H2S gas.
作者
刘敏
冯德玖
冯文林
Liu Min;Feng Dejiu;Feng Wenlin(College of Science,Chongqing University of Technology,Chongqing 400054,China;Chongqing Key Laboratory of Green Energy Materials Technology and Systems,Chongqing 400054,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2019年第10期126-131,共6页
Acta Optica Sinica
基金
国家自然科学基金(51574054)
重庆市高校创新团队项目(CXTDX201601030)
重庆市科技局社会事业与民生保障科技创新专项(cstc2017shmsA20017)
重庆市科技创新领军人才项目(CSTCCXLJRC201905)
关键词
光纤光学
光纤传感
模式干涉
二氧化钛
硫化氢
fiber optics
fiber sensing
mode interference
titanium dioxide
hydrogen sulfide
