Study on high-temperature and high-pressure measurement by using metal-coated FBG

Abstract

Metal-coated fiber Bragg grating (MFBG) sensor was proposed to measure high-temperature and high-pressure condition. Metal-coated layer of FBG improved bonding performance between metal material substrate and sensor protected as well as prolonged the lifespan of the FBG sensor. By optimized and designed thin-wall copper cylinder structure and soldered MFBG on this, we had measured high-temperature and high-pressure environments. This sensor can measure the pressure range from 0 to 40 MPa. Its correlative coefficient reached 99.95% and its sensitivity was 0.0493 nm/MPa, which was about 19 times than normal Fiber Bragg Grating. Using a thermostat, a good linearity of temperature characteristic of this structure was obtained and its correlative coefficient reached 99.904%. Temperature had been measured range from 50 to 240°C. Considering FBG intrinsic advantage, it has been applied in harsh environments such as oil-well. © 2008 Wiley Periodicals, Inc.