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US4847856A
Expired / Lapsed
US
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Phase-shift distributed-feedback semiconductor laser
Assignee: NTT Inc
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Filing: 1988-04-26
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Granted: 1989-07-11
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Expires: 2008-04-26
Abstract
Abstract A phase-shift distributed-feedback semiconductor laser includes an electrode for injecting a current to the entire area of the semiconductor laser. The laser also includes portions each for shifting an optical phase by a 1/4 wavelength at at least three locations, the number of which is an odd number. These portions are formed in a light propagation direction of the phase-shift distributed-feedback semiconductor laser structure.
Inventors
- 👤 Akira Sugimura
- 👤 Tatsuya Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:49
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/12; H01S5/06; H01S5/062; H01S5/0625; H01S5/06255; H01S5/06258; H01S5/124; H01S5/1246
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
79 words
A phase-shift distributed-feedback semiconductor laser including at least two electrodes for injecting a current to an entire area of said semiconductor laser, comprising portions, each for shifting an optical phase by a 1/4 wavelength at least three locations, the number of which is an odd number, said portions being formed inside a laser cavity in an optical path of a phase shift distributed, feedback semiconductor laser structure in a light propagation direction of the phase-shift distributed-feedback semiconductor laser structure.
Claim 2
Dependent Claim
79 words
A phase-shift distributed-feedback semiconductor laser including at least two electrodes for injecting a current to an entire area of said semiconductor laser, comprising portions, each for shifting an optical phase by a 1/4 wavelength at least three locations, the number of which is an odd number, said portions being formed inside a laser cavity in an optical path of a phase shift distributed, feedback semiconductor laser structure in a light propagation direction of the phase-shift distributed-feedback semiconductor laser structure.
Claim 3
Dependent Claim
55 words
A laser according to claim 1, wherein said phase-shift distributed-feedback semiconductor laser structure comprises a plurality of units each having said 1/4 wavelength phase-shift portion at a central portion thereof, and a 1/4 wavelength phase-shift connecting portion for connecting said units so as to shift the optical phase by a 1/4 wavelength between said units.
Claim 4
Dependent Claim
38 words
A laser according to claim 1, wherein said 1/4 wavelength phase-shift portion is constituted by a junction plane where a phase of a diffraction grating constituting said phase-shift distributed-feedback semiconductor laser structure is shifted by a 1/2 wavelength.
Claim 5
Dependent Claim
27 words
A laser according to claim 1, wherein said 1/4 wavelength phase-shift portion is formed by partially removing a diffraction grating constituting said phase-shift distributed-feedback semiconductor laser structure.
Claim 6
Dependent Claim
56 words
A laser according to claim 1, wherein said respective 1/4 wavelength phase-shift portions are formed by combining a junction plane where a phase of a diffraction grating constituting said phase-shift distributed-feedback semiconductor laser is shifted by a 1/2 wavelength and a portion obtained by partially removing said diffraction grating constituting said phase-shift distributed-feedback semiconductor laser structure.
Claim 7
Dependent Claim
27 words
A laser according to claim 1, including said 1/4 wavelength phase-shift portions, and wherein said electrode is formed on an entire surface along the light propagation direction.
Claim 8
Dependent Claim
81 words
A laser according to claim 1, wherein said 1/4 wavelength phase-shift portions are three in number, and further comprising four separate electrodes divided by said 1/4 wavelength phase-shift portions, and a common electrode formed to oppose said four separate electrodes, two inner ones of said four separate electrodes being applied with a modulation current having a polarity opposite to that applied to two outer ones of said four separate electrodes but the same magnitude as that of said two outer electrodes.
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) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |