Cavity coupled optical condition sensor
US4475812A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1981 |
| Grant date | Oct 9, 1984 |
| Priority date | — |
| Expiry date | Sep 30, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/026
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical sensor has a gain medium situated at a first location and defines one end of a resonating optical cavity. An optical fiber couples electromagnetic radiation to a predetermined point at a second location where it is directed toward a reflective surface. The physical condition to be sensed causes the reflective surface to move with respect to the end of the optical fiber. This movement essentially changes the length of the cavity in which the electromagnetic energy is resonating causing a corresponding change in the axial mode difference frequency within the cavity. A small portion of electromagnetic energy is coupled out of the cavity at the first location to a photodetector. Finally, the photodetector creates an electrical signal which varies as the change in the axial mode difference frequency, thus indicating the change in the physical condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.