High sensitivity temperature sensor based on singlemode-no-core-singlemode fibre structure and alcohol

•Optical fibre temperature sensor based on multimode interference effect and alcohol was proposed and demonstrated theoretically and experimentally.•Alcohol was chosen as the thermal sensitivity material coupled with no-core fibre in our optical fibre sensor.•The repeatability and the response time of the proposed sensor were experimentally investigated. A high sensitivity temperature sensor based on a singlemode-no-core-singlemode (SNCS) fibre structure and surrounded with alcohol within a silica capillary is described. In this investigation, no-core fibre (NCF) is used as the multimode waveguide and alcohol is chosen as the temperature sensitive medium. By packaging the alcohol solution with a short length of NCF enclosed within a silica capillary, the surrounding temperature can be detected by monitoring the variations of transmission loss at a specific wavelength. The theoretical analysis predicts this temperature sensor can provide high sensitivity, and the experimental results support this. The maximum temperature sensitivity of the sample is 0.49 dB/°C with a potential temperature resolution of 0.02 °C at the operating wavelength of 1545.9 nm. In addition, the repeatability and response time of the sensor of this investigation are investigated experimentally.