Fiber Optic Displacement Sensor for Temperature Measurement

A simple design of a temperature sensor is proposed and demonstrated using a fiber optic displacement sensor based on an intensity modulation technique. The proposed sensor uses a plastic optical fiber (POF)-based coupler as a probe in conjunction with a flat surface aluminum rod as a target. The aluminum rod is placed within the linear range of the sensor's displacement curve, which is from 0 to 1400 μm. The sensor is capable of measuring the temperature of an aluminum rod ranging from 42°C to 90°C with a measured sensitivity of 0.0044 mV/°C, with a linearity of more than 98% and a resolution of 2.4°C. The proposed sensor also shows a high degree of stability and good repeatability. The simplicity of design, accuracy, flexible dynamic range, and the low cost of fabrication are favorable attributes of the sensor and beneficial for real-field applications.