Patent US5428477A successfully refreshed from Google Patents.
US5428477A
Expired / Lapsed
US
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Optical isolator operating independent of polarization of an incident beam
Assignee: Tokin Corp
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Filing: 1993-11-19
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Granted: 1995-06-27
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Expires: 2013-11-19
Abstract
Abstract A polarization-independent optical isolator comprises three Faraday rotators and four birefringent elements. An optical arrangement of these elements is determined on the basis of the appropriate values derived from the analysis for polarization-independency. A transmission loss characteristic, which is most important in practical use of the optical isolator, is maintained at an excellent level even in presence of variation in temperature and wavelength and in presence of fluctuation in working precision. Deterioration of various isolator properties can be avoided.
Inventors
- 👤 Kenichi Siroki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:11
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: 4
Claim 1
Independent Claim
144 words
A polarization-independent optical isolator in which polarization dispersion is suppressed, comprising: four birefringent elements having birefringence; and three Faraday rotators; and wherein: said birefringent elements and said Faraday rotators are arranged along a light transmitting direction in the order of a first birefringent element, a first Faraday rotator, a second birefringent element, a second Faraday rotator, a third birefringent element, a third Faraday rotator, and a fourth birefringent element; said first, said second, said third, and said fourth birefringent elements providing polarization walk-off directions inclined at 45° to each other within a plane perpendicular to a travelling light beam; the ratio of polarization walk-off distances of said first, said second, said third and said fourth birefringent elements being 1:0.4142:0.4142:1; and said first, said second, and said third Faraday rotators providing a rotation angle of 45° for a polarization direction of said traveling light beam.
Claim 2
Dependent Claim
144 words
A polarization-independent optical isolator in which polarization dispersion is suppressed, comprising: four birefringent elements having birefringence; and three Faraday rotators; and wherein: said birefringent elements and said Faraday rotators are arranged along a light transmitting direction in the order of a first birefringent element, a first Faraday rotator, a second birefringent element, a second Faraday rotator, a third birefringent element, a third Faraday rotator, and a fourth birefringent element; said first, said second, said third, and said fourth birefringent elements providing polarization walk-off directions inclined at 45° to each other within a plane perpendicular to a travelling light beam; the ratio of polarization walk-off distances of said first, said second, said third and said fourth birefringent elements being 1:0.4142:0.4142:1; and said first, said second, and said third Faraday rotators providing a rotation angle of 45° for a polarization direction of said traveling light beam.
Claim 3
Dependent Claim
144 words
A polarization-independent optical isolator in which polarization dispersion is suppressed, comprising: four birefringent elements having birefringence; and three Faraday rotators; and wherein: said birefringence elements and said Faraday rotators are arranged along a light transmitting direction in the order of a first birefringent element, a first Faraday rotator, a second birefringent element, a second Faraday rotator, a third birefringent element, a third Faraday rotator, and a fourth birefringent element; said first, said second, said third and said fourth birefringent elements providing polarization walk-off directions inclined at 45° to each other within a plane perpendicular to a travelling light beam; the ratio of polarization walk-off distances of said first, said second, said third and said fourth birefringent elements being 0.4142:1:1:0.4142; and said first, said second, and said third Faraday rotators providing a rotation angle at 45° for a polarization direction of said travelling light beam.
Claim 4
Dependent Claim
144 words
A polarization-independent optical isolator in which polarization dispersion is suppressed, comprising: four birefringent elements having birefringence; and three Faraday rotators; and wherein: said birefringence elements and said Faraday rotators are arranged along a light transmitting direction in the order of a first birefringent element, a first Faraday rotator, a second birefringent element, a second Faraday rotator, a third birefringent element, a third Faraday rotator, and a fourth birefringent element; said first, said second, said third and said fourth birefringent elements providing polarization walk-off directions inclined at 45° to each other within a plane perpendicular to a travelling light beam; the ratio of polarization walk-off distances of said first, said second, said third and said fourth birefringent elements being 0.4142:1:1:0.4142; and said first, said second, and said third Faraday rotators providing a rotation angle at 45° for a polarization direction of said travelling light beam.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-06-26 | 1998-12-26 | 1999-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-26 | 2002-12-26 | 2003-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-26 | 2006-12-26 | 2007-06-27 | $7700.00 | Window Closed / Lapsed |