Simultaneous Measurement of Temperature and Hydrostatic Pressure Using Bragg Gratings in Standard and Grapefruit Microstructured Fibers

A novel fiber-optic sensor based on Bragg gratings in standard and grapefruit microstructured fibers (GMF) for simultaneous measurement of temperature and hydrostatic pressure is proposed and experimentally demonstrated. The temperature responses of these two gratings are almost the same due to the similar material composition in the core. The existence of large air holes in the cladding of GMF makes it experience larger axial strain than standard single-mode fiber (SMF), and therefore the pressure sensitivity of Bragg grating in GMF is much larger than that for SMF. Hence, simultaneous measurement of temperature and hydrostatic pressure can be achieved.