Research papers - Proceedings Volume 10323, 25th International Conference on Optical Fiber Sensors; 103233D (2017)
Fiber Bragg grating sensors written by femtosecond laser pulses in micro-structured fiber for downhole pressure monitoring
J.-Y. Huang, J. Van Roosbroeck, A. Bueno Martinez, T. Geernaert, F. Berghmans, C. Caucheteur, B. Van Hoe, E. Lindner, J. Vlekken
Short description
In this paper, we demonstrate that femtosecond laser pulse written fiber Bragg gratings (FBGs) fabricated in specialty highly birefringent micro-structured optical fiber (MSF) can be used for high pressure and high temperature monitoring in downhole applications. The design of the micro-structure allows encoding the pressure information into the spectral separation between the two Bragg peaks reflected by the obtained MS-FBG. We obtained a differential pressure sensitivity of 3.30 pm/bar over a pressure range from atmospheric up to 1400 bar and at temperatures between 40 °C and 290 °C. Owing to the negligible differential pressure-temperature cross-sensitivity of 6.06E-3 bar/°C, the proposed MSFBG sensor is an ideal candidate for pressure monitoring in the presence of high temperature transients.