Patent ID: 8553211
Filing Date: 2013-10-08
Classification: G01D,G01K,G01L

Abstract:
1. A method for improving reliability of a stimulated Brillouin sensing system by adding redundancy comprising the steps of: a. producing a first optical signal, said first optical signal being tunable over a pre-defined wavelength range; b. coupling said first optical signal to a fiber optic cable deployed in a region of interest, said deployed fiber optic cable comprising a plurality of spaced fiber Bragg gratings, each fiber Bragg grating having a distinct and known characteristic wavelength of reflection; c. tuning said first optical signal to the characteristic wavelength of reflection of a first chosen spaced fiber Bragg grating; d. producing a second optical signal at a fixed pre-defined wavelength, said pre-defined wavelength being outside the reflection spectrum of any of said spaced fiber Bragg gratings; e. coupling said second optical signal to said fiber optic cable; f. receiving a first reflected signal of the first optical signal, said reflected signal being reflected from the first chosen spaced fiber Bragg grating within the deployed optical cable; g. receiving a second reflected signal of the second optical signal, the second reflected signal resulting from Brillouin backscattering within the deployed optical fiber; h. measuring shifts in attributes between said second optical signal and said second reflected signal that are indicative of environmental conditions along said deployed optical fiber;