US 12,270,699 B2
Fibre optic cable sensing apparatus
Robert Ellwood, Farnborough (GB); and Alastair Godfrey, Farnborough (GB)
Assigned to OptaSense Holdings Limited
Appl. No. 17/906,566
Filed by OptaSense Holdings Limited, Camberley (GB)
PCT Filed Feb. 26, 2021, PCT No. PCT/GB2021/050497
§ 371(c)(1), (2) Date Sep. 16, 2022,
PCT Pub. No. WO2021/186147, PCT Pub. Date Sep. 23, 2021.
Claims priority of application No. 2003892 (GB), filed on Mar. 18, 2020.
Prior Publication US 2023/0160742 A1, May 25, 2023
Int. Cl. G01L 1/24 (2006.01); G01D 5/353 (2006.01); G01H 9/00 (2006.01)
CPC G01H 9/004 (2013.01) [G01D 5/35361 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A fibre optic cable structure, comprising:
an optical fibre for distributed fibre optic sensing;
the fibre optic cable structure being configured to comprise:
at least one longitudinal section of a first type which exhibits a first change in effective optical path length of the optical fibre in response to a given applied force and which is adjacent to
at least one longitudinal section of a second type which exhibits a second change in effective optical path length of the optical fibre in response to an equivalent applied force,
wherein the first change is of one polarity and the second change is of the opposite polarity.