Using fiber gratings in the short-length sensors based on micromechanical vibrations

Fiber-optic inner core gratings are considered together with the non-uniform deformations in oscillated optical-fiber. This is wide method of vibration registration as a result of appropriate deformations. The principle of such new sensors is that the resonance frequency changes under the influence of the environment. Analysis was done for fiber cantilevers with the length 1-10 mm, they vibrate by the photothermally excitation. Different cases were analyzed that correspond to transverse and longitudinal vibrations of the fiber tips or fragments with two clamps. The pi -shifted Bragg-gratings and long-period ones are discussed to measure of vibrating amplitude in different real cases. (C) 2001 Elsevier Science B.V. All rights reserved.