Study on Sensing Properties of a Temperature-Independent High Pressure Sensor Base on Tapered FBG

The sensing properties with strain and temperature of tapered FBG had been researched both theoretically and experimentally. Based on tapered FBG and thin-wall strain cylinder structure, a novel temperature-independent high pressure sensor was fabricated and investigated. The tapered FBG performed as a chirped grating, whose bandwidth and reflection power broadened and increased when the pressure applied on it. Moreover, the bandwidth and the reflection power were temperature-independent. So the value of the strain can be obtained by detecting the reflection power. This method effectively solved the cross-sensitivity problem. The experiment results indicated that this sensor provided a measurement range of 0~40MPa with a sensitivity of 0.04μw/MPa, low cost and good application prospect.