Dual stage optical device with low polarization mode dispersion and wavelength insensitivity
US5581640A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1995 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Apr 12, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/278
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention provides for a two-stage optical isolator with reduced polarization mode dispersion. Each stage has two birefringent polarizers separated by a Faraday rotator. The polarizers in each stage are oriented with respect to each other to operate conventionally as an optical isolator for light in a backward direction. However, the polarizers in each stage are oriented with respect to the polarizers in the other stage so that a polarization mode along one direction, say, the ordinary direction, of light in the first stage travelling toward the second stage is aligned along the opposite, extraordinary, direction in the second stage and vice versa. In this manner the component of any polarization travels the same optical distance through the optical isolator to substantially reduce polarization mode dispersion. The birefringent polarizers and Faraday rotators of multiple stages can also be fitted into a single magnet to substantially reduce the sensitivity of the optical isolator to changes in wavelength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.