Regenerated gratings in air-hole microstructured fibers for high-temperature pressure sensing

We present thermally regenerated fiber Bragg gratings in air-hole microstructured fibers for high-temperature, hydrostatic pressure measurements. High-temperature stable gratings were regenerated during an 800 °C annealing process from hydrogen-loaded Type I seed gratings. The wavelength shifts and separation of grating peaks were studied as functions of external hydrostatic pressure from 15 to 2400psi, and temperature from 24 °C to 800 °C. This Letter demonstrates a multiplexible pressure and temperature sensor technology for high-temperature environments using a single optical fiber feedthrough. © 2011 Optical Society of America OCIS codes: 060.2370, 060.4005, 120.5475, 120.6780. Sensors that operate at high temperatures are needed for a wide range of applications in the energy, automobile, and aerospace industries. For example, fast, accurate, and reliable interrogation of gas pressure information ensures safe and efficient operations of gas turbine, coal boilers, and power plants, where the operating tempera-tures range from 400 °C to more than 1000 °C. Optical fiber sensors have always been considered good candi