Interferometric High-Temperature Optical Fiber Sensor Sensitized by Metal Substrate
In order to achieve real-time monitoring of the temperature of the downhole submersible electric pump unit,a Mach-Zehnder interferometer(MZI)high-temperature fiber optic sensor composed of coarse cone singlemode-multimode-singlemode(CCSMS)was designed.The structure adopts a direct fusion method to fuse the single-mode fibers with the multi-mode fibers.Then,by adjusting the fusion parameters of the fusion splicer,a thick cone structure is fabricated on the single-mode fibers.Finally,the prepared structure is em-bedded in the U-shaped groove of the copper substrate to achieve the sensitization packaging of the sensor.The temperature response characteristics of the packaged sensor were tested.The experimental results show that the sensor achieves a temperature sensing sensitivity of 124.9 pm/℃ in the temperature range of 40℃ to 250℃.The stability and repeatability of the sensor were tested.The results show that the maximum stability error of the sensor is about 0.44%,and the maximum repeatability error is about 2.29 pm/℃.The sensor has the characteristics of high sensitivity,good repeatability and stability,and is expected to be used for the temperature of the electric submersible pump unit in oil and gas wells.