Gold-Coated Temperature Optical Fiber Sensor Based on a Mach-Zehnder Interferometer for Photovoltaic Monitoring

The development of a Mach-Zehnder interferometer based on tapered optical fiber for temperature sensing applications is presented. Two tapers, 24 mm apart, were fabricated on SMF-28e+ using the fusion splicer. The optical structures were coated with a 100 nm layer of gold. The influence of the gold deposition on the temperature sensitivity of the fabricated sensors is presented. The sensor was characterized in O-, S-, C-, and L-bands in a temperature range of 0-70 °C. The highest temperature sensitivity of 72 pm/°C with R² = 0.9974 was obtained for the gold-coated sensor. During the investigation, the average transmission loss was low and did not exceed 7 dB.