Reflection-type fiber-optic multimode interference structure with rounded end-face: A temperature-sensing study

We investigated a novel reflection technique for a reflection-type fiber-optic multimode interference structure. Rounding the fiber end-face increased the reflected light intensity by more than 10 dB, with no reflection coating. We demonstrated the use of our multimode interference structure as a temperature sensor by immersing the sensing region in temperature-controlled silicone oil. The resulting sensitivity was 0.028°C for a 29.60-mm sensing region.