Direct measurement of Brillouin frequency in distributed optical sensing systems
US7355163B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2005 |
| Grant date | Apr 8, 2008 |
| Priority date | — |
| Expiry date | Apr 14, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/083
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical sensing system uses light scattered from a sensing fibre to sense conditions along the fibre, and has a receiver with a frequency to amplitude converter to obtain a frequency of a Brillouin component of the received scattered light, to deduce the conditions. This converter can avoid time consuming scanning of frequencies to obtain the Brillouin frequency spectrum, and avoids the heavy processing load of deducing a peak or average frequency from the spectrum. The converter can be implemented in the optical domain using a grating or interferometer, or in the electrical domain using a diplexer or electrical interferometer. It can generate complementary signals, having opposite signs, a ratio of these signals representing the frequency. This can avoid sensitivity to amplitude changes in the received scattered signals and provide common mode rejection of noise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.