US5848203A
Expired / Lapsed
US
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Polarization-independent optical isolator
Assignee: Sumitomo Osaka Cement Co Ltd
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Filing: 1996-07-10
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Granted: 1998-12-08
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Expires: 2016-07-10
Abstract
Abstract An optical isolator for preventing reflection-returned light from entering back into the emitter of an optical system such as an optical fiber communication or an optical disc input/output device, using semiconductor laser. The polarization-independent optical isolator includes a light-emitting side optical fiber having a diameter of a core expanded to give a mode field diameter at an end face of 20 to 50 μm, a light-incident side optical fiber having a diameter of a core expanded to give a mode field diameter at an end face of 20 to 50 μm, and an optical isolator element provided between the light-emitting side optical fiber and the light-incident side optical fiber, said optical isolator element comprising a first polarization beam splitter located at a side of the light-emitting side optical fiber, a second polarization beam splitter located at a side of the light-incident side optical fiber, and a Farady rotator provided between the first polarization beam splitter and the second polarization beam splitter, and at least said first polarization beam splitter being a wedge type polarization beam splitter.
Inventors
- 👤 Shojiro Kawakami
- 👤 Kazuo Shiraishi
- 👤 Masashi Shimo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:47
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/27; G02B6/2746; G02F; G02F1/00; G02F1/01; G02F1/09; G02F1/093
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
144 words
A polarization-independent optical isolator comprising: a light-emitting side optical fiber having a diameter of a core expanded to give a mode field diameter at an end face of 20 to 50 μm; a light-incident side optical fiber having a diameter of a core expanded to give a mode field diameter at an end face of 20 to 50 μm; and an optical isolator element provided between the light-emitting side optical fiber and the light-incident side optical fiber, said optical isolator element comprising: a first polarization beam splitter located at a side of the light-emitting side optical fiber; a second polarization beam splitter located at a side of the light-incident side optical fiber; and a Farady rotator provided between the first polarization beam splitter and the second polarization beam splitter, and at least said first polarization beam splitter being a wedge type polarization beam splitter.
Claim 2
Dependent Claim
144 words
A polarization-independent optical isolator comprising: a light-emitting side optical fiber having a diameter of a core expanded to give a mode field diameter at an end face of 20 to 50 μm; a light-incident side optical fiber having a diameter of a core expanded to give a mode field diameter at an end face of 20 to 50 μm; and an optical isolator element provided between the light-emitting side optical fiber and the light-incident side optical fiber, said optical isolator element comprising: a first polarization beam splitter located at a side of the light-emitting side optical fiber; a second polarization beam splitter located at a side of the light-incident side optical fiber; and a Farady rotator provided between the first polarization beam splitter and the second polarization beam splitter, and at least said first polarization beam splitter being a wedge type polarization beam splitter.
Claim 3
Dependent Claim
63 words
The polarization-independent optical isolator set forth in claim 1, wherein in order to correct a deviation in an optical axis between ordinary rays and extra-ordinary rays caused by the first polarization beam splitter, the second polarization beam splitter and the Farady rotator during a forward propagation, an optical axis deviation-correcting element made of a parallel-faced flat plate type polarization beam splitter is provided.
Claim 4
Dependent Claim
56 words
The polarization-independent optical isolator set forth in claim 1 or 2, wherein the second polarization beam splitter is a wedge type polarization beam splitter, and the first polarization beam splitter and the second polarization beam splitter are opposed to each other and turned by a half turn around axes of the optical fibers as a center.
Claim 5
Dependent Claim
48 words
The polarization-independent optical isolator set forth in claim 1 or 2, wherein the second polarization beam splitter is a wedge type polarization beam splitter, and the first polarization beam splitter and the second polarization beam splitter are arranged at locations axially symmetrical with respect to the Farady rotator.
Claim 6
Dependent Claim
41 words
The polarization-independent optical isolator set forth in any one of claims 1 to 2, wherein an incident angle at an end face of each of the light-incident side optical fiber and the light-emitting side optical fiber is not more than 5°.
Claim 7
Dependent Claim
34 words
The polarization-independent optical isolator set forth in any one of claims 1 to 2, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a dielectric multi-layer film.
Claim 8
Dependent Claim
33 words
The polarization-independent optical isolator set forth in any one of claims 1 to 2, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a birefringent crystal.
Claim 9
Dependent Claim
41 words
The polarization-independent optical isolator set forth in any one of claims 1 to 2, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a combination of a dielectric multi-layer film and a birefringent crystal.
Claim 10
Dependent Claim
36 words
The polarization-independent optical isolator set forth in claim 3, wherein an incident angle at an end face of each of the light-incident side optical fiber and the light-emitting side optical fiber is not more than 5°.
Claim 11
Dependent Claim
36 words
The polarization-independent optical isolator set forth in claim 4, wherein an incident angle at an end face of each of the light-incident side optical fiber and the light-emitting side optical fiber is not more than 5°.
Claim 12
Dependent Claim
29 words
The polarization-independent optical isolator set forth in claim 3, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a dielectric multi-layer film.
Claim 13
Dependent Claim
29 words
The polarization-independent optical isolator set forth in claim 4, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a dielectric multi-layer film.
Claim 14
Dependent Claim
29 words
The polarization-independent optical isolator set forth in claim 5, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a dielectric multi-layer film.
Claim 15
Dependent Claim
28 words
The polarization-independent optical isolator set forth in claim 3, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a birefringent crystal.
Claim 16
Dependent Claim
28 words
The polarization-independent optical isolator set forth in claim 4, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a birefringent crystal.
Claim 17
Dependent Claim
28 words
The polarization-independent optical isolator set forth in claim 5, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a birefringent crystal.
Claim 18
Dependent Claim
36 words
The polarization-independent optical isolator set forth in claim 3, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a combination of a dielectric multi-layer film and a birefringement crystal.
Claim 19
Dependent Claim
36 words
The polarization-independent optical isolator set forth in claim 4, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a combination of a dielectric multi-layer film and a birefringement crystal.
Claim 20
Dependent Claim
36 words
The polarization-independent optical isolator set forth in claim 5, wherein the first polarization beam splitter and the second polarization beam splitter are each made of a combination of a dielectric multi-layer film and a birefringement crystal.
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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) | 2001-12-07 | 2002-06-08 | 2002-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-07 | 2006-06-08 | 2006-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-07 | 2010-06-08 | 2010-12-08 | $7700.00 | Window Closed / Lapsed |