Patent US4609257A successfully refreshed from Google Patents.
US4609257A
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Faraday rotator assembly
Assignee: Fujitsu Ltd
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Filing: 1984-04-23
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Granted: 1986-09-02
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Expires: 2004-04-23
Abstract
Abstract A Faraday rotator assembly includes a Faraday rotator of an optically transparent magnetic material; a device for applying a first magnetic field to the Faraday rotator, which field saturates the Faraday rotator with reversible magnetization; and a device for applying a second magnetic field to the Faraday rotator, the field having a direction different from that of the device for applying the first magnetic field to the Faraday rotator. The magnetization in the Faraday rotator is maintained in a saturation state by the second magnetic field at least during the reversal of the direction of the first magnetic field. The angle of the Faraday rotation of the Faraday rotator is reversed by reversing the direction of the first magnetic field.
Inventors
- 👤 Masataka Shirasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:21
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/095; G02F1/0955
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
155 words
A Faraday rotator assembly comprising: a thin plate Faraday rotator formed of an optically transparent magnetic material and arranged for passing light beams along a path in a first direction parallel to said thin plate; means for applying a first magnetic field in said first direction to the thin plate Faraday rotator, which field saturates the thin plate Faraday rotator along said path with reversible magnetization; and means for applying a second magnetic field to said thin plate Faraday rotator in a second direction that is parallel to said thin plate Faraday rotator and perpendicular to said first direction; wherein the angle of Faraday rotation of the thin plate Faraday rotator is reversed by reversing the direction of the first magnetic field, and the magnetization of the thin plate Faraday rotator is maintained in a saturation state by the second magnetic field at least during the reversing of the direction of the first magnetic field.
Claim 2
Dependent Claim
155 words
A Faraday rotator assembly comprising: a thin plate Faraday rotator formed of an optically transparent magnetic material and arranged for passing light beams along a path in a first direction parallel to said thin plate; means for applying a first magnetic field in said first direction to the thin plate Faraday rotator, which field saturates the thin plate Faraday rotator along said path with reversible magnetization; and means for applying a second magnetic field to said thin plate Faraday rotator in a second direction that is parallel to said thin plate Faraday rotator and perpendicular to said first direction; wherein the angle of Faraday rotation of the thin plate Faraday rotator is reversed by reversing the direction of the first magnetic field, and the magnetization of the thin plate Faraday rotator is maintained in a saturation state by the second magnetic field at least during the reversing of the direction of the first magnetic field.
Claim 3
Dependent Claim
17 words
A Faraday rotator assembly according to claim 1, wherein said thin plate Faraday rotator is of yttrium-iron-garnet.
Claim 4
Dependent Claim
19 words
A Faraday rotator assembly according to claim 1, wherein said thin plate Faraday rotator is a 45° Faraday rotator.
Claim 5
Dependent Claim
25 words
A Faraday rotator assembly according to claim 1, wherein said first magnetic field applying means is formed by an electromagnet formed of semi-hard magnetic material.
Claim 6
Dependent Claim
27 words
A Faraday rotator assembly according to claim 1, wherein said second magnetic field applying means comprises an electromagnet formed of a soft magnetic material and a coil.
Claim 7
Dependent Claim
18 words
A Faraday rotator assembly according to claim 5, wherein said soft magnetic material is permalloy or soft iron.
Claim 8
Dependent Claim
27 words
A Faraday rotator assembly according to claim 1, wherein said second magnetic field applying means comprises a predetermined one of permanent magnets and a soft magnetic material.
Claim 9
Dependent Claim
24 words
A Faraday rotator assembly according to claim 1, wherein said first and second magnetic fields are in the range from 100 to 150 oersted.
Claim 10
Dependent Claim
21 words
A Faraday rotator assembly according to claim 1, wherein the thickness of said thin plates Faraday rotator is about 200 μm.
References Cited (Backward Citations)
US3515457A
Cited
US4355864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |