Method and apparatus for the elimination of polarization fading in interferometric sensing systems
US6731389B2 · kind B2 · utility
22Cited by
9References
8Claims
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Key dates
| Filing date | May 8, 2002 |
| Grant date | May 4, 2004 |
| Priority date | — |
| Expiry date | Jun 4, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an interferometric sensing apparatus, a scrambler is positioned in front of a polarizer, followed by a detector. In that way, although the two beams remain orthogonal to each other, they are continuously rotated, relative to the polarizer. In some positions, both beams pass through the polarizer and interfere, thus eliminating polarization fading. The signal is amplitude modulated at the rotation frequency of the scrambler, but this modulation is removed by low pass filtering.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.