US4751719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distributed feedback semiconductor laser device
Assignee: NEC Corp
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Filing: 1986-06-10
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Granted: 1988-06-14
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Expires: 2006-06-10
Abstract
Abstract Laser chips which are stably operated in a single mode result from a semiconductor laser device in which a diffraction grating is formed neighboring an active layer. The distribution of current to be injected into the active layer is controlled to a configuration which substantially corresponds to that of the distribution of the field intensity of light along the laser optical axis inside the active layer.
Inventors
- 👤 Ikuo Mito
- 👤 Masayuki Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:32
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/06; H01S5/062; H01S5/0625; H01S5/10; H01S5/12; H01S5/06255; H01S5/06258; H01S5/20; H01S5/22; H01S5/227; H01S5/2275; H01S5/2277
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
84 words
A semiconductor laser device comprising: an active layer for emitting light in response to the injection of current; a diffraction grating disposed at least substantially adjacent to said active layer, for interacting with said light; current injecting means for injecting current into said active layer; and control means for controlling the distribution of the current injected into said active layer such that said current distribution approximates a field intensity distribution of light in the direction of the laser optical axis inside said active layer.
Claim 2
Dependent Claim
84 words
A semiconductor laser device comprising: an active layer for emitting light in response to the injection of current; a diffraction grating disposed at least substantially adjacent to said active layer, for interacting with said light; current injecting means for injecting current into said active layer; and control means for controlling the distribution of the current injected into said active layer such that said current distribution approximates a field intensity distribution of light in the direction of the laser optical axis inside said active layer.
Claim 3
Dependent Claim
41 words
A semiconductor laser device as claimed in claim 1, wherein said current injecting means comprises positive and negative electrodes, that one of said positive and negative electrodes which is closer to said active layer comprising a plurality of separated individual electrodes.
Claim 4
Dependent Claim
20 words
A semiconductor laser device as claimed in claim 2, wherein load resistors are connected to each of said individual electrodes.
Claim 5
Dependent Claim
50 words
A semiconductor laser device as claimed in claim 3, wherein said individual electrodes are interconnected by fusing the same to a like number of wirings, said wirings in turn being individually fused to said load resistors, said load resistors being additionally fused to a terminal provided on a heat sink.
Claim 6
Dependent Claim
59 words
A semiconductor laser derive as claimed in claim 1, wherein said semiconductor laser device includes a cladding layer which neighbors said active layer and which is greater in bandgap than said active layer, said cladding layer having a resistivity which varies in the direction of the laser optical axis and in correspondence with the field intensity distribution of light.
Claim 7
Dependent Claim
30 words
A semiconductor laser device as claimed in claim 1, wherein said diffraction grating includes a phase shifted region where a phase of said diffraction grating is shifted by a quarter-wave.
Claim 8
Dependent Claim
25 words
A semiconductor laser device as claimed in claim 6, wherein opposite ends of said active layer are provided with a reflective film of low reflectivity.
Claim 9
Dependent Claim
41 words
A semiconductor laser derice as claimed in claim 1, wherein one of said opposite ends of said active layer is provided with a reflective film of high reflectivity and the other end is provided with a reflective film of low reflectivity.
Claim 10
Dependent Claim
60 words
A semiconductor laser as claimed in claim 1, wherein said current injecting means comprises at least two separated electrode surfaces formed over or under said active layer, and wherein said control means comprises resistances electrically connected to said separated electrode surfaces, said resistances being varied in resistivity so as to selectively vary the current density distribution within said active layer.
Claim 11
Dependent Claim
60 words
A semiconductor laser as claimed in claim 8, wherein said current injecting means comprises at least two separated electrode surfaces formed over or under said active layer, and wherein said control means comprises resistances electrically connected to said separated electrode surfaces, said resistances being varied in resistivity so as to selectively vary the current density distribution within said active layer.
Claim 12
Dependent Claim
48 words
A semiconductor laser as claimed in claim 1, wherein said control means comprises at least one cladding layer adjacent said active layer, said cladding layer including at least one region having a carrier density substantially varied from the carrier density exhibited by other regions of said cladding layer.
Claim 13
Dependent Claim
33 words
A semiconductor laser as claimed in claim 11, wherein said at least one region comprises a region including a diffused impurity in a sufficient concentration to materially lower the resistivity of the same.
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) | 1991-06-14 | 1991-12-14 | 1992-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-14 | 1995-12-14 | 1996-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-14 | 1999-12-14 | 2000-06-14 | $7700.00 | Window Closed / Lapsed |