US 11,898,919 B2
Fiber optic pressure sensor
Vahid Sotoudeh, Los Altos, CA (US); Behzad Moslehi, Los Altos, CA (US); Joshua Kuehn, Boulder Creek, CA (US); and Richard J. Black, Menlo Park, CA (US)
Assigned to Intelligent Fiber Optic Systems Corporation, Fremont, CA (US)
Filed by Intelligent Fiber Optic Systems Corporation, San Jose, CA (US)
Filed on Nov. 4, 2021, as Appl. No. 17/518,598.
Prior Publication US 2023/0136164 A1, May 4, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G01L 1/24 (2006.01); G01L 1/22 (2006.01); G01K 11/3206 (2021.01)
CPC G01L 1/246 (2013.01) [G01K 11/3206 (2013.01); G01L 1/2281 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for measuring pressure applied to a first surface of a diaphragm, the diaphragm comprising a common sidewall of a first aperture and a second aperture parallel to the first aperture, the diaphragm having a second surface opposite the first surface, the method operative on a first optical fiber with a first fiber Bragg grating (FBG) attached to a region of changed strain of the second surface upon application of pressure to the first surface of the diaphragm, the second surface having a region of unchanged strain upon application of pressure to the first surface of the diaphragm, the region of unchanged strain thermally coupled to the region of changed strain, the region of unchanged strain also having a second FBG attached to the second surface, the method comprising:
application of a pressure to the diaphragm sufficient to cause a change in a reflected or transmitted wavelength of the first FBG;
measuring a first FBG wavelength and a second FBG wavelength;
converting the first FBG wavelength and the second FBG wavelength into a pressure measurement, and optionally a temperature measurement;
where the converting the first FBG wavelength and the second FBG wavelength into a pressure measurement comprising Pml or Pm2 is one of:
Pm1=C1λ1m1−C1λ01+C2λ2m1−C2λ02
Pm2=C1λ1m2−C1λ01+C2λ2m2−C2λ02
where:
C1, C2, λ01 , and λ02 are calibration constants.