Temperature Dependence of a Refractive Index Sensor Based on Side-Polished Macrobending Plastic Optical Fiber

The temperature dependence of a refractive index (RI) sensor based on a side-polished macrobending plastic optical fiber was investigated experimentally. By extracting pure temperature dependence of the sensor alone, the influence of temperature to the sensor was characterized and corrected. It is found that the equivalent thermo-optic coefficient of the sensor monotonically decreases with RI of measured liquid increasing, and equals zero at a certain RI of environment. Therefore, it is feasible to make a temperature insensitive device by coating a suitable RI material, which may have potential applications in other sensing areas.