High sensitivity ammonia gas sensor based on a silica gel coated microfiber coupler

Lei Sun, Yuliya Semenova, Qiang Wu, Dejun Liu, Jinhui Yuan, Tao Ma, XinZhu Sang, Binbin Yan, Kuiru Wang, Chongxiu Yu, Gerald Farrell

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28 Citations (Scopus)
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In this paper, a high sensitivity ammonia gas sensor is proposed based on a silica gel coated microfiber coupler (MFC). The MFC structure is formed by the two tapered fibers with 3 μm waist diameter each, which were fabricated by using a customized microheater brushing technique. Silica gel coating was prepared by a sol-gel technique and applied on the surface of the MFC as a thin layer. The spectral characteristics of the proposed sensor were studied under various ammonia gas concentrations. The experimental results show that the coating thickness strongly affected the sensitivity of the MFC-based sensor to ammonia gas concentration. For the sensor with a 90 nm silica gel coating thickness, the highest measurement sensitivity is 2.23 nm/ppm for ammonia gas concentration, and the resolution is as good as 5 ppb, while the measured response and recovery times are ~ 50 and 35 seconds, respectively. Finally, it is demonstrated that the proposed sensor offers good repeatability and selectivity to ammonia gas.
Original languageEnglish
Pages (from-to)2864-2870
JournalJournal of Lightwave Technology
Issue number14
Early online date5 May 2017
Publication statusPublished - Jul 2017


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