Optical sensing device containing fiber Bragg gratings
US6674928B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 2001 |
| Grant date | Jan 6, 2004 |
| Priority date | — |
| Expiry date | Feb 8, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L1/246
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A new optical sensing device containing fiber Bragg gratings, a scanning bandpass filter, an interferometer and multiple photodetectors is disclosed. The present invention also describes a new system and method for fibre Bragg grating (FBG) sensor interrogation and multiplexing. The new system combines a scanning Fabry-Perot (SFP) bandpass filter used to wavelength-multiplex multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fibre interferometer made with a 3×3 coupler to detect strain-induced wavelength shifts. A passive technique for interferometer drift compensation using non-sensing FBGs is included in the system. A complete prototype system interrogates four gratings in a single fiber at a Nyquist sampling rate up to 10 kHz, with a noise floor measured near 4 n&egr; Hz−1/2 above 0.1 Hz. The inclusion of the interferometer drift compensation technique is shown to make quasi-static measurements feasible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.