High-sensitivity temperature sensor based on overlay on side-polished fibers

A temperature sensor based on overlay on side-polished fibers is presented. It works on the basis of the evanescent field coupling between a single-mo de side-polished optical fiber and a dielectric waveguide overlay. The spec trum of a white light beam transmitted through the former system exhibit sh arp and deep regularly spaced resonances whose central wavelengths are line arly shifted with temperature. It has a wavelength sensitivity of similar t o 1 nm/degrees C, which is one order of magnitude better than that obtained with fiber Bragg sensors.