US5315431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical isolator
Assignee: FDK Corp
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Filing: 1992-12-30
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Granted: 1994-05-24
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Expires: 2012-12-30
Abstract
Abstract A non-reciprocal unit and a parallel-surfaced flat birefringent plate are provided between incident side and outgoing side fiber collimators. The non-reciprocal unit is formed by disposing two tapered birefrigent plates, one on each side of a 45° Faraday rotator consisting of a cylindrical permanent magnet and a magneto-optical element housed in the magnet. The optical axes of the parallel-surfaced flat birefringent plate and adjacent tapered birefringent plate are staggered from each other by 90°. The thickness of the parallel-surfaces birefringent plate is set equal to the sum of the thicknesses of the two tapered birefringent plates.
Inventors
- 👤 Akihiro Masuda
- 👤 Ikuo Maeda
- 👤 Hideaki Yuri
- 👤 Yoichi Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:01
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/27; G02B6/2746; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/093; G02F2203/00; G02F2203/06; Y; Y10; Y10S; Y10S372/00; Y10S372/703
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
118 words
A non-polarization-mode-dispersing optical isolator comprising: a cylindrical casing, a non-reciprocal unit, in said casing, having a 45° Faraday rotator and two tapered birefringent plates on opposite sides of said Faraday rotator, fiber collimators on opposite sides of said non-reciprocal unit, said fiber collimators including a first fiber collimator connected to a first optical fiber and a second fiber collimator connected to a second optical fiber, and a parallel-surfaced flat birefringent plate between said non-reciprocal unit and one of said fiber collimators, wherein said parallel-surfaced flat birefringent plate is fixed within said casing with an optical axis of said parallel-surfaced flat birefringent plate is staggered at 90° from an axis of an adjacent one of said tapered birefringent plate.
Claim 2
Dependent Claim
118 words
A non-polarization-mode-dispersing optical isolator comprising: a cylindrical casing, a non-reciprocal unit, in said casing, having a 45° Faraday rotator and two tapered birefringent plates on opposite sides of said Faraday rotator, fiber collimators on opposite sides of said non-reciprocal unit, said fiber collimators including a first fiber collimator connected to a first optical fiber and a second fiber collimator connected to a second optical fiber, and a parallel-surfaced flat birefringent plate between said non-reciprocal unit and one of said fiber collimators, wherein said parallel-surfaced flat birefringent plate is fixed within said casing with an optical axis of said parallel-surfaced flat birefringent plate is staggered at 90° from an axis of an adjacent one of said tapered birefringent plate.
Claim 3
Dependent Claim
49 words
A non-polarization-mode-dispersing optical isolator according to claim 1, wherein said tapered birefringent plates and said parallel-surfaced birefringent plates are made of monocrystalline rutile, and a thickness of said parallel-surfaced birefringent plate is substantially equal to a sum of thickness of optical path passing portions of said tapered birefringent plates.
Claim 4
Dependent Claim
36 words
A non-polarization-mode-dispersing optical isolator according to claim 2, wherein said tapered birefringent plates are inclined so that optical axes of said tapered birefringent plates are positioned in a perpendicular plane with respect to an incident light.
Claim 5
Dependent Claim
41 words
A non-polarization-mode-dispersing optical isolator according to claim 1, wherein said fiber collimators includes an incident fiber collimator and an outgoing fiber collimator, each of said fiber collimators having a metal sleeve, a spherical lens and a ferrule in said metal sleeve.
Claim 6
Dependent Claim
27 words
A non-polarization-mode-dispersing optical isolator according to claim 1, wherein said Faraday rotator has a cylindrical permanent magnet and a magneto-optical element made of monocrystalline yttrium iron garnet.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-23 | 1997-11-22 | 1998-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-23 | 2001-11-22 | 2002-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-23 | 2005-11-22 | 2006-05-24 | $7700.00 | Window Closed / Lapsed |