Optical sensor system
US4294513A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1979 |
| Grant date | Oct 13, 1981 |
| Priority date | — |
| Expiry date | Sep 11, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S177/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical transducer with an optical waveguide having two paths for the propagation of light is deformed in response to acoustical pressure variations or other parameters to be sensed to modulate the amplitude of the light propagated along the two paths in opposite polarities. The light outputs of the two paths are sensed by photodetectors and applied to an electrical differencing circuit. The mean values of the photodetector outputs are balanced as by mechanically providing a predetermined bias deformation of the fiber, or by electrically matching outputs of the detectors such that, on the average, the output of the differencing circuit is zero. Dynamic deformation of the fiber in the transducer results in unbalanced outputs of the photodetectors which unbalance is sensed by the differencing circuit. This differential detection method minimizes optical and mechanical sources of noise in the light source and waveguide and leads to increased signal-to-noise and enhanced dynamic range of the transducer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.