US 12,436,043 B2
Methods providing distributed temperature and strain measurements and related sensors
Matthew Joseph Murray, Alexandria, VA (US); Joseph Brady Murray, Ellicott City, MD (US); Hannah Marie Ogden, Glen Burnie, MD (US); and Brandon F. Redding, University Park, MD (US)
Assigned to The Government of the United States of America, as represented by the Secretary of the Navy, Arlington, VA (US)
Filed by The Government of the United States of America, as represented by the Secretary of the Navy, Arlington, VA (US)
Filed on Sep. 26, 2023, as Appl. No. 18/474,855.
Claims priority of provisional application 63/377,620, filed on Sep. 29, 2022.
Prior Publication US 2024/0118144 A1, Apr. 11, 2024
Int. Cl. H04B 10/00 (2013.01); G01D 5/353 (2006.01); G01K 11/322 (2021.01)
CPC G01K 11/322 (2021.01) [G01D 5/35364 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method providing temperature measurements and strain measurements distributed along an optical fiber having a first end and a second end, the method comprising:
coupling a plurality of Brillouin pump laser pulses into a first end of the optical fiber, wherein each of the plurality of Brillouin pump laser pulses has a Brillouin pump frequency;
coupling Brillouin Stokes and Brillouin Anti-Stokes probe laser beams into the second end of the optical fiber, wherein the Brillouin Stokes probe laser beam has a Brillouin Stokes probe frequency, wherein the Brillouin Anti-Stokes probe laser beam has a Brillouin Anti-Stokes probe frequency, and wherein the Brillouin Stokes probe frequency, the Brillouin Anti-Stokes probe frequency, and the Brillouin pump frequency are included in a Brillouin frequency band;
coupling a plurality of Rayleigh seed pulses of a Rayleigh seed pulse train into the optical fiber, wherein each of the plurality of Rayleigh seed pulses of the Rayleigh seed pulse train has a respective different frequency included in a Rayleigh frequency band, and wherein the Brillouin and Rayleigh frequency bands are mutually exclusive;
coupling frequencies included in the Brillouin frequency band from the first end of the optical fiber to a Brillouin detector;
coupling Rayleigh backscatter signals included in the Rayleigh frequency band from the optical fiber to a Rayleigh detector;
calculating the strain measurements and the temperature measurements at different positions distributed along the optical fiber based on outputs from the Brillouin detector and based on outputs from the Rayleigh detector.