US 12,168,928 B2
Grating position dithering for improved distributed acoustic sensing engineered fiber performance
William Johnston, Houston, TX (US); Paul Wysocki, Blacksburg, VA (US); and Dan Provenzano, Blacksburg, VA (US)
Assigned to Baker Hughes Oilfield Operations LLC, Houston, TX (US)
Filed by Baker Hughes Oilfield Operations LLC, Houston, TX (US)
Filed on Nov. 11, 2021, as Appl. No. 17/524,615.
Prior Publication US 2023/0141615 A1, May 11, 2023
Int. Cl. G02B 6/293 (2006.01); E21B 47/135 (2012.01); G01V 8/16 (2006.01); H04B 10/25 (2013.01)
CPC E21B 47/135 (2020.05) [G01V 8/16 (2013.01); G02B 6/2931 (2013.01); H04B 10/25 (2013.01)] 13 Claims
OG exemplary drawing
 
1. An optical system for measuring an acoustic signal, comprising:
an optical interrogator configured to transmit a light pulse;
an optical fiber for receiving the light pulse, the optical fiber having a plurality of nominal sites uniformly spaced apart along a longitudinal axis of the optical fiber; and
a plurality of gratings formed in the optical fiber, each of the plurality of gratings associated with a nominal site and separated from its associated nominal site by an offset distance, wherein the offset distance is a random value within a dithering range, the dithering range having an average value of zero, wherein the plurality of gratings comprises a plurality of chirped Fiber Bragg gratings.