Multimode interference-based fiber-optic strain and temperature sensor using polarization-maintaining fiber

A cost-efficient fiber-optic strain and temperature sensor has been proposed and demonstrated experimentally. The sensor consists of a segment of polarization-maintaining fiber (PMF) and two segments of multimode fiber (MMF). Two segments of MMF, which are used as beam splitter and combiner, are embedded on both ends of the PMF. The all-fiber sensor is put in the middle of the single-mode fiber. Due to the ratio of the strain and temperature responses of the sensor, the measurement of strain and temperature can be achieved by monitoring the transmission spectrum. The experimental result shows that the strain sensitivity is up to −3.16 pm / μϵ in the range of 0 to 1000 μϵ and the temperature sensitivity is 0.071 nm / ° C in the range from 10°C to 45°C. This sensor exhibits the advantages of low cost and high sensitivity and may have potential application in strain and temperature measurement.