Patent ID: 9297691
Filing Date: 2016-03-29
CPC Classification: G01D,G01H

Claim Text:
1. A fiber Bragg grating (FBG) interrogation system, the system comprising: a broad band spectrum (BBS) light source; a first FBG receiving an optic signal from the light source, wherein the first FBG filters the optic signal and transmits a transmitted signal, and the transmitted signal has a first central wavelength in a resting state; a second FBG receiving the transmitted signal from the first FBG, wherein the second FBG reflects a second central wavelength to produce a reflected signal, and the second central wavelength of the reflected signal matches the first central wavelength when the second FBG is in the resting state; an optical coupler coupled to the first and second FBG, wherein the optical coupler receives the transmitted signal and the reflected signal and provides an output signal; and a photodetector coupled to the optical coupler to receive the output signal, wherein the photodetector detects a minimum amount of energy when the first central wavelength of the transmitted signal and the second central wavelength of the reflected signal match, thereby indicating vibration is absent, and wherein further the photodetector detects an increased energy when the first central wavelength of the transmitted signal and the second central wavelength of the reflected signal are mismatched, thereby indicating vibration is present.