Optical isolator employing multipass faraday rotation
US4909612A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1986 |
| Grant date | Mar 20, 1990 |
| Priority date | — |
| Expiry date | Jul 14, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/093
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical Faraday isolator includes a slab of Faraday rotator medium coated to define input and output faces and internal reflective surfaces for causing the beam to travel between the input and output faces along a zig-zag path. Permanent magnets polarized in a direction normal to the plane defined by the zig-zag beam path are disposed on opposite sides of the beam path. The magnets are paired on each side with serially alternating polarity and the like poles are in transverse registration on opposite sides of the beam path to produce an intense, unidirectional magnetic field parallel to the beam path within the rotator slab. A quarterwave plate introduces a compensating amount of elliptical polarization to cancel unwanted elliptical polarization effects of the slab and its coatings. A beam shaving aperture at the exit of the slab shaves off divergent backward travelling rays.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.