US4932034A
Expired / Lapsed
US
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Distributed feedback semiconductor laser device and current injection
Assignee: KDDI Corp
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Filing: 1989-09-27
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Granted: 1990-06-05
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Expires: 2009-09-27
Abstract
Abstract A distributed feedback semiconductor device is disclosed which has a diffraction grating disposed near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors and n- and p-side electrodes for injection a current into the active layer, one of the n- and p-side electrodes being divided into a plurality of electrodes, and in which a current is injected into the active layer across the n- and p-side electrodes for laser oscillation to obtain output light. A first current source is connected to each of electrodes into which one of the n- and p-side electrodes is divided, and a second current source is connected to the divided electrodes via resistors, for injecting a current into the active layer in a desired ratio. The first and second current sources are controlled in accordance with the light emitting state of the active layer. In operation, a current is injected into the active layer through the divided electrodes while controlling the injected-current density in the active layer to be uniform in the direction of travel of light until the injected current reaches a threshold current at which the distributed feedback semiconductor laser device starts to oscillate, and a current thereafter injected while controlling the injected-current density to be maximum in at least that region of the active layer in which the light intensity is maximum in the direction of travel of light.
Inventors
- 👤 Masashi Usami
- 👤 Shigeyuki Akiba
- 👤 Yuichi Matsushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:00
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/16; H01S5/164; H01S5/06; H01S5/062; H01S5/0625; H01S5/068; H01S5/0683; H01S5/12; H01S5/06255; H01S5/06258; H01S5/06832; H01S5/124
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
A distributed feedback semiconductor laser device which is provided with a diffraction grating provided near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors, and n- and p-side electrodes for injecting a current into the active layer, characterized by the provision of: a first current source connected to each of electrodes into which one of the n- and p-side electrodes is divided; and a second current source connected to the divided electrodes via resistors, for injecting a current into the active layer in a desired ratio; the first and second current sources being controlled in accordance with the light emitting state of the active layer.
Claim 2
Dependent Claim
115 words
A distributed feedback semiconductor laser device which is provided with a diffraction grating provided near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors, and n- and p-side electrodes for injecting a current into the active layer, characterized by the provision of: a first current source connected to each of electrodes into which one of the n- and p-side electrodes is divided; and a second current source connected to the divided electrodes via resistors, for injecting a current into the active layer in a desired ratio; the first and second current sources being controlled in accordance with the light emitting state of the active layer.
Claim 3
Dependent Claim
70 words
A distributed feedback semiconductor laser device according to claim 1, characterized in that the first current source injects a current into the active layer uniformly via the divided electrodes and the second current source injects a current into the active layer via the divided electrodes so that the current density is maximum in that region of the active layer where the light intensity is higher than in the other regions.
Claim 4
Dependent Claim
36 words
A distributed feedback semiconductor laser device according to claim 1, characterized in that one of the divided electrodes is disposed on that region of the active layer where the diffraction grating has a phase shift point.
Claim 5
Dependent Claim
39 words
A distributed feedback semiconductor laser device according to claim 3, characterized in that the current density in the region where the diffraction grating has the phase shift point becomes higher than in the other regions of the active layer.
Claim 6
Dependent Claim
28 words
A distributed feedback semiconductor laser device according to claim 1, characterized in that the one of the divided electrodes is disposed in the center of the active layer.
Claim 7
Dependent Claim
186 words
A current injection method for a distributed feedback semiconductor laser device which has a diffraction grating disposed near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors and n- and p-side electrodes for injection a current into the active layer, one of the n- and p-side electrodes being divided into a plurality of electrodes, and in which a current is injected into the active layer across the n- and p-side electrodes for laser oscillation to obtain output light, characterized by the inclusion of: a first step of injecting a current into the active layer through the divided electrodes while controlling the injected-current density in the active layer to be uniform in the direction of travel of light until the injected current reaches a threshold current at which the distributed feedback semiconductor laser device starts to oscillate; and a second step of injecting a current thereafter while controlling the injected-current density to be maximum in at least that region of the active layer in which the light intensity is maximum in the direction of travel of light.
Claim 8
Dependent Claim
186 words
A current injection method for a distributed feedback semiconductor laser device which has a diffraction grating disposed near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors and n- and p-side electrodes for injection a current into the active layer, one of the n- and p-side electrodes being divided into a plurality of electrodes, and in which a current is injected into the active layer across the n- and p-side electrodes for laser oscillation to obtain output light, characterized by the inclusion of: a first step of injecting a current into the active layer through the divided electrodes while controlling the injected-current density in the active layer to be uniform in the direction of travel of light until the injected current reaches a threshold current at which the distributed feedback semiconductor laser device starts to oscillate; and a second step of injecting a current thereafter while controlling the injected-current density to be maximum in at least that region of the active layer in which the light intensity is maximum in the direction of travel of light.
Claim 9
Dependent Claim
180 words
A distributed feedback semiconductor laser device comprising: a diffraction grating provided near a light emitting active layer, a double hetero structure with the active layer sanwiched between an n-type semiconductor and a p-type semiconductor, and an n-side electrode and a p-side electrode one of which is divided into several electrodes for injecting a current into the active layer, characterized by the provision of: a first current source connected to each of said several divided electrodes into which one of the n-side electrode and the p-side electrode is divided; a plurality of resistors equal in number to said several divided electrodes and connected thereto; a second current source connected to the divided electrodes via corresponding resistors, for injecting a current into the active layer at a desired ratio in current density for each of the divided electrodes; and control means comprising a photodiode disposed for absorbing a backward output light from the active layer to produce output light employed for controlling the first current source and the second current source in accordance with the light emitting state of the active layer.
Claim 10
Dependent Claim
180 words
A distributed feedback semiconductor laser device comprising: a diffraction grating provided near a light emitting active layer, a double hetero structure with the active layer sanwiched between an n-type semiconductor and a p-type semiconductor, and an n-side electrode and a p-side electrode one of which is divided into several electrodes for injecting a current into the active layer, characterized by the provision of: a first current source connected to each of said several divided electrodes into which one of the n-side electrode and the p-side electrode is divided; a plurality of resistors equal in number to said several divided electrodes and connected thereto; a second current source connected to the divided electrodes via corresponding resistors, for injecting a current into the active layer at a desired ratio in current density for each of the divided electrodes; and control means comprising a photodiode disposed for absorbing a backward output light from the active layer to produce output light employed for controlling the first current source and the second current source in accordance with the light emitting state of the active layer.
Claim 11
Dependent Claim
78 words
A distributed feedback semiconductor laser device according to claim 7, characterized in that the first current source is connected directly to said divided electrodes and injects a current into the active layer uniformly via the divided electrodes, and the second current source injects a current into the active layer via the divided electrodes so that the current density is maximum in that region of the active layer where the light intensity is higher than in the other regions.
Claim 12
Dependent Claim
38 words
A distributed feedback semiconductor laser device according to claim 7, characterized in that a center one of the divided electrodes is disposed overlying a region of the active layer where the diffraction grating has a phase shift point.
Claim 13
Dependent Claim
38 words
A distributed feedback semiconductor laser device according to claim 9, characterized in that the current density in the region where the diffraction grating has the phase shift point is higher than in other regions of the active layer.
Claim 14
Dependent Claim
26 words
A distributed feedback semiconductor laser device according to claim 7, characterized in that said one of the divided electrodes overlies the center of the active layer.
Claim 15
Dependent Claim
191 words
A current injection method for a distributed feedback semiconductor laser during which has a diffraction grating disposed near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors and n- and p-side electrodes for injecting a current into the active layer, one of the n- and p-side electrodes being divided into a plurality of electrodes, and in which a current is injected into the active layer across the n- and p-side electrodes for laser oscillation to obtain output light, characterized by including of: a first step of injecting a current into the active layer through the divided electrodes while controlling the injected-current density in the active layer to be uniform in the direction of travel of light until the injected current reaches a threshold current at which the distributed feedback semiconductor laser device starts to oscillate; and a second step of injecting a current into the active layer through the divided electrodes thereafter while controlling the injected-current density to maximize it in that region of the active layer in which the light intensity is maximum in the direction of travel of light.
Claim 16
Dependent Claim
191 words
A current injection method for a distributed feedback semiconductor laser during which has a diffraction grating disposed near a light emitting active layer, a double hetero structure with the active layer sandwiched between n- and p-type semiconductors and n- and p-side electrodes for injecting a current into the active layer, one of the n- and p-side electrodes being divided into a plurality of electrodes, and in which a current is injected into the active layer across the n- and p-side electrodes for laser oscillation to obtain output light, characterized by including of: a first step of injecting a current into the active layer through the divided electrodes while controlling the injected-current density in the active layer to be uniform in the direction of travel of light until the injected current reaches a threshold current at which the distributed feedback semiconductor laser device starts to oscillate; and a second step of injecting a current into the active layer through the divided electrodes thereafter while controlling the injected-current density to maximize it in that region of the active layer in which the light intensity is maximum in the direction of travel of light.
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) | 1993-06-04 | 1993-12-04 | 1994-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-04 | 1997-12-04 | 1998-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-04 | 2001-12-04 | 2002-06-05 | $7700.00 | Window Closed / Lapsed |