US 9,869,795 B2 · Distributed acoustic sensing system with variable spatial resolution

Abstract

Systems and methods for distributed acoustic sensing based on coherent Rayleigh scattering are disclosed herein. A system comprises a pulse generator, an optical fiber coupled to the pulse generator, an interferometer coupled to the optical fiber, a photodetector assembly coupled to the interferometer, and an information handling system, which activates two optical gain elements so as to vary the optical path length of the interferometer. A method comprises sending an optical pulse down an optical fiber, splitting backscattered light from the optical pulse into a first backscattered pulse and a second backscattered pulse, activating a first optical gain element and a second optical gain element, sending the first backscattered pulse into a first arm of an interferometer, sending the second backscattered pulse into a second arm of an interferometer, combining the first and second backscattered pulses to form an interferometric signal, and receiving the interferometric signal at a photodetector assembly.

Claims20

Dependent claims

A distributed acoustic sensing system based on coherent Rayleigh scattering, comprising:

a pulse generator, which generates an optical pulse;
an optical fiber coupled to the pulse generator;
an interferometer coupled to the optical fiber, further comprising:
a first interferometer arm coupled to a first optical gain element;
a second interferometer arm coupled to a second optical gain element;
and
a third interferometer arm coupled to a third optical gain element;
a photodetector assembly coupled to the interferometer, wherein the photodetector assembly detects backscattered interfered light;
and
an information handling system, which activates two optical gain elements of the first optical gain element, the second optical gain element, and the third optical gain element so as to vary the optical path length of the interferometer, thereby changing the spatial resolution of the system.

7 more elements

A method for distributed acoustic sensing comprising:

sending a first optical pulse down an optical fiber, wherein light from the first optical pulse is backscattered from positions along the length of the optical fiber according to coherent Rayleigh scattering;
splitting backscattered light from the first optical pulse into a first backscattered pulse and a second backscattered pulse;
activating a first optical gain element and a second optical gain element;
sending the first backscattered pulse into a first arm of an interferometer, the first arm of the interferometer comprising the first optical gain element;
sending the second backscattered pulse into a second arm of an interferometer, the second arm of the interferometer comprising the second optical gain element;
combining the first and second backscattered pulses to form an interferometric signal;
receiving the interferometric signal at a photodetector assembly;
providing output relating to the interferometric signal to an information handling system.

5 more elements

Dependencies are inferred from the claim text.

Distributed acoustic sensing system with variable spatial resolution

Life of this patent

Distributed acoustic sensing system with variable spatial resolution

Life of this patent

Abstract

Claims20