Method and apparatus for compensating for the residual birefringence in interferometric fiber-optic gyros
US5365337A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1992 |
| Grant date | Nov 15, 1994 |
| Priority date | — |
| Expiry date | Oct 28, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C19/728
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interferometric fiber-optic gyro system includes a light source and a plurality of optical fiber rings employed to measure angular displacement along three axes. Optical circuit elements interposed between the source and the rings include an optical switch for periodically applying the optical signal to each of the rings individually along three separate optical transmission paths. Included in each of the optical transmission paths is a modal filter, including a polarizer, and a beam splitter which provides two separate beams to the optical ring for counter-propagation through the ring. Compensating birefringent devices are added in the optical circuits to compensate for a residual birefringence introduced by the various optical elements in the circuits. The characteristics of the compensating devices consist of predetermined lengths of polarization preserving, single-mode optical fiber. The birefringence of each of the optical devices is characterized in terms of a total number of beat lengths. A plus or minus sign is assigned to the value of the beat lengths, depending upon the optical axis of the optical device being measured. The birefringent compensating optical fiber is se…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.