Thermally compensated reference interferometer and method
US4890922A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 27, 1989 |
| Grant date | Jan 2, 1990 |
| Priority date | — |
| Expiry date | Feb 27, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/225
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A first birefringent material is positioned to receive an optical signal output from an optical source. A second birefringent material is positioned to receive the signal transmitted through the first birefringent material. The birefringence of the first birefringent material is modulated to produce a modulation in the phase difference between two polarizations propagated between the birefringent materials. A detector forms an electrical signal indicative of the phase shift produced by the first and second birefringent materials between a pair of orthogonal polarizations in the optical signal received by the first birefringent material. This phase shift is opposite to phase shifts caused by changes in the source wavelength. A feedback signal indicative of the hase shift caused by the crystals is fed back to the optical source to stabilize its frequency. The system produces a temperature-independent phase shift between the two polarizations by means of proper selection of the lengths of the crystals in the optical path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.