Multimode interference based fiber-optic sensor for temperature measurement

Abstract

A new fiber-optic sensor was demonstrated for temperature measurement using multimode interference effect in single mode multimode single mode (SMS) fiber structure. Interference fringes were found to red-shift as the temperature increased and vice versa due to the thermo-optic effect, which changed the phase of the core and cladding modes inside the structure. The sensor probes were shown to measure temperature stably with a linearity of more than 99%. The temperature sensitivity of the SMS sensor was 21 pm/?C, which is twice the sensitivity of the conventional fiber Bragg grating sensor. Our proposed sensor is simple, cost-effective, and could operate at high temperatures.