Strain sensor with optical fibre Bragg gratings
AssigneeEuropean Community represented by Commission of the European Communities
InventorsRobert Patrick Kenny, Maurice Patrick Whelan, Alfredo Carlo Lucia
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Abstract
Strain sensors, and in particular strain rosettes, are described and claimed, in which the strain sensing elements are fiber Bragg gratings. Strain sensors in accordance with the described invention comprise first and second fiber Bragg gratings, and a length of optical fiber connecting the gratings in series, each grating being substantially straight and the two gratings being non-parallel and having different nominal Bragg wavelengths, the connecting length of optical fiber having a bend, characterised in that a portion of the connecting length is tapered, the tapered portion including an elongate waist portion having a reduced cross sectional area and said bend is formed in the waist portion.
Claims14
A strain sensor comprising:
- first and second fibre Bragg gratings, and
- a length of optical single mode fibre connecting the gratings in series,
- each grating being substantially straight,
- the first and second gratings being non-parallel and having different nominal Bragg wavelengths,
- the connecting length of optical single mode fibre having a bend and including a portion that is tapered including an elongate waist portion having a reduced cross-sectional area,
- said bend being formed in the waist portion.
Dependencies are inferred from the claim text.