LAUSR

Abstract A miniature inline fiber temperature sensor is developed based on a silica capillary partially filled with ethanol. The working mechanism of the sensor is based on anti-resonant reflecting waveguide. Owing to the large thermal expansion coefficient of ethanol compared with the silica capillary, the liquid level inside the capillary can be well raised along with the increase in the external temperature. At the same time, the anti-resonance leakage is suppressed and the optical power of the loss dips at the resonant wavelengths will increase. The experimental results demonstrate a temperature sensitivity 0.42 dB/°C at 1133 nm within 25–65 °C temperature range. Our sensor has its potential in temperature measurement due to the merits of compact structure, small size, low cost, and so on.