US4775980A
Expired / Lapsed
US
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Distributed-feedback semiconductor laser device
Assignee: Hitachi Ltd
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Filing: 1985-07-26
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Granted: 1988-10-04
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Expires: 2005-07-26
Abstract
Abstract A distributed feedback semiconductor laser provided with a grating which effects optical feedback by means of periodic corrugation disposed inside an optical resonator. The optical resonator has at least two regions having different Bragg wavelengths, and these regions are arranged longitudinally in the direction of an optical axis. The laser device can realize stable single longitudinal mode oscillation through variation of the refractive indexes of the regions nonuniformly around an average value.
Inventors
- 👤 Naoki Chinone
- 👤 Shinji Tsuji
- 👤 Yoshihisa Fujisaki
- 👤 Yasutoshi Kashiwada
- 👤 Motohisa Hirao
- 👤 Hitoshi Nakamura
- 👤 Akio Oishi
- 👤 Kenji Hiruma
- 👤 Tadashi Fukuzawa
- 👤 Hiroyoshi Matumura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:36
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/18; H01S5/183; H01S5/18305; H01S5/12; H01S5/1053; H01S5/106; H01S5/1206; H01S5/1215; H01S5/1225; H01S5/18308; H01S5/20; H01S5/2054; H01S5/2059; H01S5/2072
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
152 words
In a distributed feedback semiconductor laser device, an arrangement comprising: an active layer for emitting light by an injected carrier; a cladding layer for confining said light in said active layer; and an optical guiding layer for guiding said light, said optical guiding layer including a grating which effects optical feedback by means of periodic corrugation, wherein said active layer is formed between said cladding layer and said optical guiding layer to form an optical resonator, wherein said optical resonator is comprised of a predetermined plurality of regions which have different Bragg wavelengths from one another, wherein said plurality of regions of said optical resonator are disposed longitudinally in the direction of an optical axis of said optical resonator, and wherein said optical resonator has a plurality of refractive indexes in the direction of said optical axis in each of said regions of said optical resonator arranged nonuniformly around an average value.
Claim 2
Dependent Claim
152 words
In a distributed feedback semiconductor laser device, an arrangement comprising: an active layer for emitting light by an injected carrier; a cladding layer for confining said light in said active layer; and an optical guiding layer for guiding said light, said optical guiding layer including a grating which effects optical feedback by means of periodic corrugation, wherein said active layer is formed between said cladding layer and said optical guiding layer to form an optical resonator, wherein said optical resonator is comprised of a predetermined plurality of regions which have different Bragg wavelengths from one another, wherein said plurality of regions of said optical resonator are disposed longitudinally in the direction of an optical axis of said optical resonator, and wherein said optical resonator has a plurality of refractive indexes in the direction of said optical axis in each of said regions of said optical resonator arranged nonuniformly around an average value.
Claim 3
Dependent Claim
42 words
The distributed feedback semiconductor laser device as claimed in claim 1, wherein each of said plurality of regions of said optical resonator comprises said grating having periodic corrugations with a period which differs from that of other regions of said optical resonator.
Claim 4
Dependent Claim
37 words
The distributed feedback semiconductor laser device as claimed in claim 1, wherein the thickness of said optical guiding layer in one region of said optical resonator is different than that in other regions of said optical resonator.
Claim 5
Dependent Claim
40 words
The distributed feedback semiconductor laser device as defined in claim 2, wherein said regions of said optical resonator comprise a plurality of regions of said grating having different distances between said active layer and the surface of said periodic corrugation.
Claim 6
Dependent Claim
63 words
The distributed feedback semiconductor laser device as defined in claim 1, wherein said regions of said optical resonator comprise a plurality of regions of said grating having a difference of thickness in semiconductor layers having a smaller refractive index than an active layer existing on a side opposite to the side on which said corrugation exists, with said active layer being the center.
Claim 7
Dependent Claim
33 words
The distributed feedback semiconductor laser device as defined in claim 1, wherein the respective thickness of active layers of a plurality of said regions of said optical resonator are different from one another.
Claim 8
Dependent Claim
29 words
The distributed feedback semiconductor laser device as defined in claim 1, wherein respective optical guiding layers of a plurality of said regions of said optical resonator have different compositions.
Claim 9
Dependent Claim
33 words
The distributed feedback semiconductor laser device as defined in claim 1, wherein the respective thickness of cladding layers of a plurality of said regions of said optical resonator are different from one another.
Claim 10
Dependent Claim
61 words
In a semiconductor laser device, an arrangement comprising: an active layer which emits light; and a structure which forms a cavity with said active layer, wherein said structure is covered by a photoelectric field of said light and has effective refractive indexes thereof varied periodically and nonuniformly around an average value in a direction of an optical axis of said cavity.
Claim 11
Dependent Claim
61 words
In a semiconductor laser device, an arrangement comprising: an active layer which emits light; and a structure which forms a cavity with said active layer, wherein said structure is covered by a photoelectric field of said light and has effective refractive indexes thereof varied periodically and nonuniformly around an average value in a direction of an optical axis of said cavity.
Claim 12
Dependent Claim
23 words
A semiconductor laser device according to claim 9, wherein a period of repetition of said variation of said effective refractive indexes is fixed.
Claim 13
Dependent Claim
129 words
In a distributed feedback semiconductor laser device an arrangement comprising: a semiconductor substrate; stacked semiconductor layers formed on the semiconductor substrate, said stacked layers including an optical guiding layer and an active layer contacting the optical guiding layer, wherein an optical resonator is comprised of the optical guiding layer and the active layer, and further wherein said optical resonator includes a predetermined plurality of regions which have different Bragg wavelengths from one another; wherein the plurality of regions of the optical resonator are disposed longitudinally in a direction of an optical axis of the optical resonator, and wherein the optical resonator has a plurality of refractive indexes in the direction of the optical axis in each of the regions of the optical resonator arranged nonuniformly around an average value.
Claim 14
Dependent Claim
129 words
In a distributed feedback semiconductor laser device an arrangement comprising: a semiconductor substrate; stacked semiconductor layers formed on the semiconductor substrate, said stacked layers including an optical guiding layer and an active layer contacting the optical guiding layer, wherein an optical resonator is comprised of the optical guiding layer and the active layer, and further wherein said optical resonator includes a predetermined plurality of regions which have different Bragg wavelengths from one another; wherein the plurality of regions of the optical resonator are disposed longitudinally in a direction of an optical axis of the optical resonator, and wherein the optical resonator has a plurality of refractive indexes in the direction of the optical axis in each of the regions of the optical resonator arranged nonuniformly around an average value.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-10-04 | 1992-04-04 | 1992-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-04 | 1996-04-04 | 1996-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-04 | 2000-04-04 | 2000-10-04 | $7700.00 | Window Closed / Lapsed |