EP0406005A2
Expired / Lapsed
EP
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Semiconductor laser and manufacture method therefor
Assignee: Optical Measurement Technology Development Co Ltd
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Filing: 1990-06-29
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Granted: —
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Expires: 2010-06-29
Abstract
Abstract This invention relates to a distributed feedback semiconductor laser having a diffractive grating on an active layer (7) in order to generate stimulated emission by recombining electrons with positive holes thereon by the light distributed feedback. This invention laser can achieve precisely single wavelength longitudinal mode lasing as a thin buffer layer (6) is grown on the surface of the semiconductor layer (4) which has been etched with irregular pattern corresponding to the diffractive grating (5) while the corrugated pattern is being maintained intact and an active layer (7) is grown on the surface thereof in a manner to fill in the dents of the corrugated pattern (5) as much as possible so that a diffractive grating is formed on the active layer (7) and light distributed feedback is caused mainly by the periodic perturbation of gain coefficients stimulated by the diffractive grating.
Inventors
- 👤 Kunio Tada
- 👤 Yoshiaki Nakano
- 👤 Yi Luo
- 👤 Takeshi Inoue
- 👤 Haruo Hosomatsu
- 👤 Hideto Iwaoka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 16:39
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/30; H01S5/34; B; B82; B82Y; B82Y20/00; H01S5/10; H01S5/12; H01S5/1228
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
63 words
A semiconductor laser which includes an active region for generating light, and a diffraction grating for reflecting the light generated by the active region, in order to produce stimulated light emissions, characterised in that, the diffraction grating is a boundary of, or lies in, the active region of the semiconductor laser, and the active region has a crystal structure with substantially no irregularities.
Claim 2
Dependent Claim
63 words
A semiconductor laser which includes an active region for generating light, and a diffraction grating for reflecting the light generated by the active region, in order to produce stimulated light emissions, characterised in that, the diffraction grating is a boundary of, or lies in, the active region of the semiconductor laser, and the active region has a crystal structure with substantially no irregularities.
Claim 3
Dependent Claim
17 words
A semiconductor laser as claimed in claim 1, wherein the active region is a deposited epitaxial layer.
Claim 4
Dependent Claim
63 words
A semiconductor laser as claimed in claim 2, wherein the active region is a deposited epitaxial layer lying on a support region which has corrugations lying transverse to the direction in which light travels in the active region, and the active region has corrugations set by those of the support region, the pitch of the corrugations setting the operating frequency of the laser.
Claim 5
Dependent Claim
52 words
A semiconductor laser as claimed in claim 2, wherein the active region is a deposited epitaxial layer which includes a plurality of quantum well regions spaced evenly in the direction in which light travels in the active region, the spacing of the quantum well regions setting the operating frequency of the laser.
Claim 6
Independent Claim
63 words
A method of fabricating a semiconductor laser which includes an active region for generating light, and a diffraction grating for reflecting the light generated by the active region, in order to produce stimulated light emissions, characterised in that, the active region is deposited, epitaxially, on a support region, and the diffraction grating is formed at a boundary of, or in, the active region.
Claim 7
Independent Claim
63 words
A method of fabricating a semiconductor laser which includes an active region for generating light, and a diffraction grating for reflecting the light generated by the active region, in order to produce stimulated light emissions, characterised in that, the active region is deposited, epitaxially, on a support region, and the diffraction grating is formed at a boundary of, or in, the active region.
Claim 8
Dependent Claim
60 words
A method of fabricating a semiconductor laser as claimed in claim 5, wherein the active region is deposited on a support region which has corrugations which lie transverse to the direction in which light travels in the active region, to form an active region with a corrugated boundary, the pitch of the corrugations setting the operating frequency of the laser.
Claim 9
Dependent Claim
68 words
A method of fabricating a semiconductor laser as claimed in claim 5, wherein the active region is deposited with a quantum well region, and the quantum well region ia separated, by ion implantation, into a plurality of separate quantum well regions evenly spaced in the direction in which light travels in the active region, the spacing of the quantum well regions setting the operating frequency of the laser.
Claim 10
Dependent Claim
96 words
A semiconductor laser including an active layer to generate stimulated emission, and a diffraction grating on the active layer to give light distributed feedback, which is characterized in that said diffraction grating is formed on one of the surfaces of said active layer as a corrugated pattern with dents and projections, a thin semiconductor buffer layer (6) is provided in contact with the corrugated pattern formed on said surface, and said corrugated pattern is substantially congruent with the corrugated pattern etched on a semiconductor layer (4) which contacts with the other surface of the buffer layer.
Claim 11
Dependent Claim
96 words
A semiconductor laser including an active layer to generate stimulated emission, and a diffraction grating on the active layer to give light distributed feedback, which is characterized in that said diffraction grating is formed on one of the surfaces of said active layer as a corrugated pattern with dents and projections, a thin semiconductor buffer layer (6) is provided in contact with the corrugated pattern formed on said surface, and said corrugated pattern is substantially congruent with the corrugated pattern etched on a semiconductor layer (4) which contacts with the other surface of the buffer layer.
Claim 12
Dependent Claim
35 words
The semiconductor laser as claimed in Claim 8, wherein said buffer layer has a uniform thickness, and the corrugated patterns on both surfaces of the layer are parallel to each other across the buffer layer.
Claim 13
Dependent Claim
20 words
The semiconductor laser as claimed in Claim 8, wherein the thickness of said buffer layer is 0.01 to 1 µm.
Claim 14
Dependent Claim
22 words
The semiconductor laser as claimed in Claim 8, wherein the active layer (7) includes either single or multi quantum well layer (7W).
Claim 15
Dependent Claim
192 words
A semiconductor laser having an active layer to generate stimulated emission and a diffraction grating on the active layer to give light distributed feedback, which is characterized in that said diffraction grating is formed on one of the surfaces of said active layer (7) in a corrugated pattern with dents and projections, the active layer (7) has the structure to change the thickness distribution according to the corrugated shapes thereof, a thin semiconductor buffer layer (6) is provided in contact with the corrugated pattern formed on said surface of the active layer (7), a semiconductor layer (4) the corrugated pattern etched with is provided in contact with the other surface of the buffer layer, said buffer layer (6) is of the structure which is epitaxially grown to transmit the corrugated pattern etched on the semiconductor layer (4) on which the other surface of the buffer layer (6) is in contact to the corrugated pattern formed on said active layer (7), and said buffer layer (6) includes at least partially a buffer layer (6a) which is shaped to emphasize the corrugated pattern with the dents and projections etched on said semiconductor layer (4).
Claim 16
Dependent Claim
192 words
A semiconductor laser having an active layer to generate stimulated emission and a diffraction grating on the active layer to give light distributed feedback, which is characterized in that said diffraction grating is formed on one of the surfaces of said active layer (7) in a corrugated pattern with dents and projections, the active layer (7) has the structure to change the thickness distribution according to the corrugated shapes thereof, a thin semiconductor buffer layer (6) is provided in contact with the corrugated pattern formed on said surface of the active layer (7), a semiconductor layer (4) the corrugated pattern etched with is provided in contact with the other surface of the buffer layer, said buffer layer (6) is of the structure which is epitaxially grown to transmit the corrugated pattern etched on the semiconductor layer (4) on which the other surface of the buffer layer (6) is in contact to the corrugated pattern formed on said active layer (7), and said buffer layer (6) includes at least partially a buffer layer (6a) which is shaped to emphasize the corrugated pattern with the dents and projections etched on said semiconductor layer (4).
Claim 17
Dependent Claim
57 words
A semiconductor laser including an active layer to generate stimulated emission and a diffraction grating on the active layer to give light distributed feedback, which is characterized in that said active layer (7) includes either single or multiple quantum well layer (7W), and the quantum well layer is disordered according to the period of said diffraction grating.
Claim 18
Dependent Claim
57 words
A semiconductor laser including an active layer to generate stimulated emission and a diffraction grating on the active layer to give light distributed feedback, which is characterized in that said active layer (7) includes either single or multiple quantum well layer (7W), and the quantum well layer is disordered according to the period of said diffraction grating.
Claim 19
Dependent Claim
86 words
A manufacturing method for distributed feedback semiconductor laser comprising a step of etching a surface of a semiconductor layer in the pattern corresponding to a diffraction grating, a step of growing a thin buffer layer on the surface of the semiconductor layer while maintaining the corrugated pattern intact, and a step of growing an active layer for generating stimulated emission above the corrugated pattern in a manner to fill the dents thereof, the corrugated pattern on the surface of the buffer layer being the diffraction grating.
Claim 20
Dependent Claim
86 words
A manufacturing method for distributed feedback semiconductor laser comprising a step of etching a surface of a semiconductor layer in the pattern corresponding to a diffraction grating, a step of growing a thin buffer layer on the surface of the semiconductor layer while maintaining the corrugated pattern intact, and a step of growing an active layer for generating stimulated emission above the corrugated pattern in a manner to fill the dents thereof, the corrugated pattern on the surface of the buffer layer being the diffraction grating.
Claim 21
Dependent Claim
37 words
The semiconductor laser manufacture method as claimed in Claim 14, wherein the growth rate in the step to grow said active layer is set lower than the growth rate in the step to grow said buffer layer.
Claim 22
Dependent Claim
25 words
The semiconductor laser manufacture method as claimed in Claim 14, wherein the step to grow said buffer layer includes metal organic vapor phase epitaxy method.
Claim 23
Dependent Claim
30 words
The semiconductor laser manufacture method as claimed in Claim 14, wherein said semiconductor layer is one of the cladding layers which is provided to contain lights within said active layer.
Claim 24
Dependent Claim
35 words
The semiconductor laser manufacture method as claimed in Claim 14, wherein said semiconductor layer is another semiconductor layer provided on a surface of one of the cladding layers for containing lights within said active layer.
Claim 25
Dependent Claim
30 words
The semiconductor laser manufacture method as claimed in Claim 14, wherein the step to etch the corrugated pattern on said semiconductor layer includes steps of interference exposure and anisotropic etching.
Claim 26
Dependent Claim
56 words
The semiconductor laser manufacture method as claimed in Claim 14, wherein the step to grow said buffer layer includes a step to emphasize a part of the corrugated pattern etched on the surface of said semiconductor layer by utilizing the condition that a growth is produced with emphasis selectively on a part of a crystal face.
Claim 27
Dependent Claim
118 words
The semiconductor laser manufacture method as claimed in Claim wherein the step to grow said buffer layer includes a step to grow a first buffer layer in a manner to shape it with emphasis on a part of the corrugated pattern etched on said semiconductor layer and a step to grow a second buffer layer in a suitable form as the diffraction grating for the active layer on said first buffer layer, and the step to grow said first buffer layer is executed under the condition that the growth is not produced or less produced on the {111} B face, and the step to grow said second buffer layer is executed under the conditions other than the above.
Claim 28
Dependent Claim
87 words
A semiconductor laser manufacture method comprising a first step to grow a first cladding layer, a second step to grow an active layer upon the first cladding layer, and a third step to grow a second cladding layer upon said active layer, said second step including a step to form an active layer having a quantum well layer, which is characterized in that a step to disorder said quantum well layer at the period of diffraction grating is included between said second step and said third step.
Claim 29
Dependent Claim
87 words
A semiconductor laser manufacture method comprising a first step to grow a first cladding layer, a second step to grow an active layer upon the first cladding layer, and a third step to grow a second cladding layer upon said active layer, said second step including a step to form an active layer having a quantum well layer, which is characterized in that a step to disorder said quantum well layer at the period of diffraction grating is included between said second step and said third step.
Claim 30
Dependent Claim
54 words
The semiconductor laser manufacture method as claimed in Claim 22, wherein said step to disorder includes a step to form masks on the active layer formed in said second step in accordance with said period, and a step to implant ions from above the active layer which has partially been covered with the masks.
Claim 31
Dependent Claim
42 words
The semiconductor laser manufacture method as claimed in Claim 22, wherein the step to disorder includes a step to inject ion beams intermittently in accordance with the period of said diffraction grating from above the active layer formed in said second step.
References Cited (Backward Citations)
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