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2. ENGINEERING AND TECHNOLOGY
The humidity and temperature responses of a microfiber coupler (MFC) coated with silica gel are investigated. Two MFC structures with different waist diameters of 2.5 and 3.5 μm were fabricated by fusing and tapering two single-mode fibers using a microheater brushing technique. The influences of the coating thickness and tapered waist diameter on the sensing performance are analyzed. For the proposed sensor with a waist diameter of 2.5 μm and 8-layers thick coating, the change in the relative humidity (RH) results in an exponential blueshift with a maximum sensitivity of 1.6 nm/% RH in the range from 70 to 86% RH. In response to the temperature change, the sensor’s transmission spectrum redshifts in a linear fashion with an average sensitivity of 0.55 nm/°C in the range from 20 to 40 °C. The study is important for the development of the proposed fiber structure as a humidity or temperature sensor.
Semenova, Y., Liu, Dejun & Farrell, G. (2016). Investigation of humidity and temperature response of a silica gel coated microfiber coupler. IEEE Potonics Journal, vol. 8, no. 6, 2016. doi:10.1109/JPHOT.2016.2619479