DISTRIBUTED ACOUSTIC SENSING SYSTEM WITH VARIABLE SPATIAL RESOLUTION

摘要

Systems and methods for distributed acoustic sensing based on coherent Rayleigh scattering are disclosed herein. A system comprises a pulse generator, optical fibers coupled to the pulse generator, an interferometer coupled to the optical fibers, a photodetector assembly coupled to the interferometer, and an information handling system configured to detect a difference in backscattered light from the optical fibers. A method comprises sending an optical pulses down optical fibers, receiving backscattered light from the optical pulses, combining the backscattered light from the optical pulses to form an interferometric signal, receiving the interferometric signal at a photodetector assembly, and determining a difference in the interferometric signal at an information handling system.

主权项

1. A distributed acoustic sensing system, comprising:
a pulse generator configured to generate optical pulses; a first optical fiber coupled to the pulse generator, the first optical fiber configured to selectively receive the an optical pulse from the pulse generator based on activation of a first optical gain element, the first optical fiber comprising a first coating configured to alter a length of the first optical fiber when exposed to an electromagnetic signal; a second optical fiber coupled to the pulse generator, the second optical fiber configured to selectively receive an optical pulse from the pulse generator based on activation of a second optical gain element; an interferometer coupled to the first optical fiber and the second optical fiber, the interferometer configured to receive backscattered light from the an optical pulse traveling through the first optical fiber or the second optical fiber, the interferometer comprising:
a first interferometer arm coupled to a third optical gain element;a second interferometer arm coupled to a fourth optical gain element; anda third interferometer arm coupled to a fifth optical gain element; a photodetector assembly coupled to the interferometer, the photodetector assembly configured to detect backscattered light from the interferometer and generate an electronic signal based on the backscattered light; and an information handling system, which:
activates one optical gain element of the first optical gain element and the second optical gain elements so as to determine which optical fiber of the first optical fiber and the second optical fiber an optical pulse generated by the pulse generator may travel through,activates two optical gain elements of the third optical gain element, the fourth optical gain element, and the fifth optical gain element so as to vary the optical path length of the interferometer, thereby changing the spatial resolution of the system, anddetermines a difference between backscattered light from a first optical pulse that selectively travels through the first optical fiber and backscattered light from a second optical pulse that selectively travels through the second optical fiber.