Sensor systems employing optical fiber gratings
US5397891A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 3, 1993 |
| Grant date | Mar 14, 1995 |
| Priority date | — |
| Expiry date | May 3, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2006/12164
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
One or more optical fiber gratings are used to sense environmental effects that can vary the spacing between the lines of the grating to vary the center frequency of the spectral envelope, either reflected or passed thereby. Light of the sensor grating's spectral envelope is transmitted to a local optical filter unaffected by the environmental effect and compared with the spectral envelope of the local optical filter to produce an intensity modulated signal, which is detected to sense the environmental effect. The sensor systems so constructed may have one or more local optical filters and those local optical filters may be modulated to reduce the effects of noise, broaden the dynamic range, vary the sensitivity or discriminate in a multiplexed embodiment. The system can be operated either open or closed loop. In addition, the fiber grating may have multiple gratings at the same location so that different kinds of effects or effects from different directions can be sensed from a single location.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.