Fiber optic sensor
US4647203A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1985 |
| Grant date | Mar 3, 1987 |
| Priority date | — |
| Expiry date | Mar 7, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/266
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical fibre Fabry-Perot etalon can be used as a sensor if the parameter being monitored is allowed to influence the etalon's length, e.g. by pressure, temperature, magneto-strictive effects, piezo-electric effects, acoustically, etc. However, with single-mode fibre and only one set of peaks in the transmission function the device is direction insensitive so that the sign of the parameter being monitored cannot be detected. In the present arrangement the etalon is driven in such a way as to support two different path-length distinct transmission modes, e.g. by the use as a light source of a laser emitting light at 1.3 micrometers wavelength. Two sequences of peaks are then produced in the transmission function which are peaks of different sizes, so that the transmission function is asymmetrical. The peaks are separated at the detection circuitry by discriminations followed by pulse counting means so that the arrangement becomes sign responsive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.