High sensitivity long-period grating-based temperature monitoring using a wide wavelength range to 2.2 μm

Temperature effects on the various cladding modes of a long-period grating (LPG) fabricated in B-Ge co-doped fibre have been investigated to create a high sensitivity measurement device. The temperature sensitivities of the attenuation bands of the LPG over the wavelength region 1.2-2.2 mu m, for a grating with a 330 mu m period, were obtained by monitoring the wavelength shift of each attenuation band, with a temperature increment of 20 degrees C, over the range from 23 degrees C to 140 degrees C. The attenuation band appearing over the 1.8-2.0 mu m wavelength range has shown a nearly five times higher temperature sensitivity than that of lower order modes, and thus it shows significant promise for fibre optic temperature sensor applications. (c) 2006 Elsevier B.V. All rights reserved.