Patent US4941738A successfully refreshed from Google Patents.
US4941738A
Expired / Lapsed
US
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Polarization independent optical amplifier apparatus
Assignee: AT&T Inc
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Filing: 1988-07-29
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Granted: 1990-07-17
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Expires: 2008-07-29
Abstract
Abstract A polarization independent semiconductor amplifier is used in a double-pass configuration; that is, the output of the amplifier is passed through a 45° Faraday rotator to a mirror and then through the rotator and the amplifier again. Polarization independent gain is thus achieved.
Inventors
- 👤 Nils A. Olsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:18
CPC Classifications
G; G02; G02F; G02F2/00; H; H01; H01S; H01S5/00; H01S5/50; H01S5/5009; H01S5/5018; G02F1/00; G02F1/01; G02F1/09; G02F1/093; Y; Y10; Y10S; Y10S372/00; Y10S372/703
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
110 words
Optical amplifier apparatus for amplifying optical radiation having arbitrary polarization, amplification being independent of said polarization, said apparatus comprising an optical amplifier which has different gains for TE and TM modes of said optical radiation, means for transmitting both polarizations of said radiation essentially simultaneously through said amplifier, and means located external to any resonator for rotating both of said polarizations of said radiation by n90°, where n is an odd integer, after it emanates from said amplifier and for transmitting said polarization-rotated radiation through said amplifier again so that the gains of said TE and TM modes passing through said amplifier an even number of times are essentially equal.
Claim 2
Dependent Claim
110 words
Optical amplifier apparatus for amplifying optical radiation having arbitrary polarization, amplification being independent of said polarization, said apparatus comprising an optical amplifier which has different gains for TE and TM modes of said optical radiation, means for transmitting both polarizations of said radiation essentially simultaneously through said amplifier, and means located external to any resonator for rotating both of said polarizations of said radiation by n90°, where n is an odd integer, after it emanates from said amplifier and for transmitting said polarization-rotated radiation through said amplifier again so that the gains of said TE and TM modes passing through said amplifier an even number of times are essentially equal.
Claim 3
Dependent Claim
61 words
The apparatus of claim 1 wherein said rotating means comprises a rotator and a mirror arranged in tandem with said amplifier, said rotator being effective to rotate the polarization of said radiation by 45° in a single-pass therethrough and said mirror is positioned to reflect said polarization-rotated radiation for re-transmission through said amplifier, thereby to experience another 45° of polarization rotation.
Claim 4
Independent Claim
15 words
The apparatus of claims 1 or 2 wherein said amplifier comprises a semiconductor optical amplifier.
Claim 5
Dependent Claim
14 words
The apparatus of claim 3 wherein said amplifier is a non-resonant semiconductor optical amplifier.
Claim 6
Dependent Claim
14 words
The apparatus of claim 3 wherein said rotating means includes a Faraday optical rotator.
Claim 7
Dependent Claim
20 words
The apparatus of claim 3 wherein said transmitting means comprises an optical coupler for coupling said radiation to said amplifier.
Claim 8
Dependent Claim
21 words
The apparatus of claim 3 wherein said transmitting means comprises a polarization-independent optical circulator for coupling said radiation to said amplifier.
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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) | 1993-07-16 | 1994-01-15 | 1994-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-16 | 1998-01-15 | 1998-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-16 | 2002-01-15 | 2002-07-17 | $7700.00 | Window Closed / Lapsed |