US 12,241,794 B2
System and method for determining changes of an optical fibre
Roy Josefsson, Hoekerum (SE); and Daniel Eckerström, Bankeryd (SE)
Assigned to SAAB AB, Linkoeping (SE)
Filed by SAAB AB, Linkoeping (SE)
Filed on Mar. 21, 2022, as Appl. No. 17/655,605.
Application 17/655,605 is a continuation of application No. 17/647,190, filed on Jan. 6, 2022, granted, now 12,031,871.
Application 17/647,190 is a continuation of application No. 16/269,776, filed on Feb. 7, 2019, granted, now 11,248,969, issued on Feb. 15, 2022.
Claims priority of application No. 1850330-0 (SE), filed on Mar. 23, 2018.
Prior Publication US 2022/0214229 A1, Jul. 7, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G01K 11/3206 (2021.01); G01D 3/10 (2006.01); G01D 5/353 (2006.01); G01K 11/32 (2021.01); G01L 1/24 (2006.01); G01M 3/00 (2006.01); G01M 3/38 (2006.01)
CPC G01K 11/3206 (2013.01) [G01D 3/10 (2013.01); G01D 5/35316 (2013.01); G01D 5/35387 (2013.01); G01D 5/3539 (2013.01); G01K 11/32 (2013.01); G01L 1/246 (2013.01); G01M 3/002 (2013.01); G01M 3/38 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method for determining strain changes of an optical fibre (250) having Fiber Bragg Grating (FBG) patterns provided in at least one portion (Portion 1) of said optical fibre (250), said optical fibre (250) being connected between a first detector arrangement (210) and a second detector arrangement (220), wherein said first detector arrangement (210) comprises a first light emitting device (231), a first light detecting device (232) and a first control arrangement (233; 500), wherein said second detector arrangement (220) comprises a second light emitting device (241), a second light detecting device (242) and a second control arrangement (243; 500), the optical fibre (250) comprises a core and a casing, wherein the length of the core of the optical fibre (250) is longer than the casing of the optical fibre (250); the method comprising the steps of:
emitting (s410) light into said optical fibre (250) in a first direction (D1) from said first detector arrangement (210), receiving reflections from said FBG patterns of such emitted light by said first detector arrangement (210), and processing said reflections for determining a current strain change related to said optical fibre (250);
on the basis of predetermined criteria, emitting (s440) light into said optical fibre (250) in an opposite, second, direction (D2) from said second detector arrangement (220), receiving reflections from said FBG patterns of such emitted light by said second detector arrangement (220), and processing said reflections for determining a current strain change related to said optical fibre (250).