Optical-fiber measuring device, gyrometer, central navigation and stabilizing system
US5141316A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1990 |
| Grant date | Aug 25, 1992 |
| Priority date | — |
| Expiry date | Nov 16, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C19/726
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a fibre optic measuring device of the type in which the change in a measured parameter generates a phase difference between two waves in a SAGNAC ring interferometer (2). Electronic means (7) comprise a processing system (9) delivering a signal depending on the measured parameter and electronic means (12) controlling the phase modulator (4). The electronic means (12) produce a control signal for the modulator determined in such a way that the phase difference .delta..PHI..sub.m which it produces between the counter-propagating waves periodically takes the following four successive values: ##EQU1## where .PHI..sub.o is a constant phase shift and it depends on a, and a is a positive constant satisfying the condition: cos .PHI..sub.o =cos a.PHI..sub.o. The gain of the channel for controlling the modulation is kept constant by producing a signal depending on the said gain by exploiting the four values x1, x2, x3, x4 delivered in response to a period of the modulation signal according to the expression (x1+x3)-(x2+x4), the said signal acting on the modulator in such a way as to keep the gain constant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.