US5444730A
Expired / Lapsed
US
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Single-wavelength semiconductor laser
Assignee: Canon Inc
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Filing: 1994-06-20
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Granted: 1995-08-22
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Expires: 2014-06-20
Abstract
Abstract A single wavelength semiconductor laser comprises a laser cavity portion and a mode selector portion. The laser cavity portion includes a waveguide and perturbation means for imparting a periodical perturbation to the waveguide. The laser cavity portion functions as a mode selecting reflective mirror for coupling two modes, which have different absolute values of propagation constants, to each other, accompanied with a mode conversion. The two coupled modes respectively travel forward and rearward along the waveguide to constitute two degenerate laser resonance modes. The mode selector portion selectively outputs a predetermined laser resonance mode out of the two degenerate laser resonance modes, and the mode selector portion is structured so that light returning to the semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes. Thus, a dynamic single wavelength semiconductor laser is obtained, which is insensitive to returning light, even without use of any isolator.
Inventors
- 👤 Natsuhiko Mizutani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:49
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/1028; H01S5/1032; H01S2301/00; H01S2301/14; H01S2301/145; H01S5/06; H01S5/0601; H01S5/0607; H01S5/062; H01S5/0625; H01S5/1035; H01S5/1082
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
129 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide and perturbation means for imparting a periodical perturbation to said waveguide, and said laser cavity means functioning as a mode selecting reflective mirror for coupling two modes, which have different absolute values of propagation constants, to each other, accompanied with a mode conversion, said two coupled modes respectively travelling forward and rearward along said waveguide to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 2
Dependent Claim
129 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide and perturbation means for imparting a periodical perturbation to said waveguide, and said laser cavity means functioning as a mode selecting reflective mirror for coupling two modes, which have different absolute values of propagation constants, to each other, accompanied with a mode conversion, said two coupled modes respectively travelling forward and rearward along said waveguide to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 3
Dependent Claim
39 words
A single wavelength semiconductor laser according to claim 1, wherein said laser cavity means includes loss means for suppressing the mode conversion in which the absolute value of the propagation constant remains unchanged and the sign thereof is inverted.
Claim 4
Dependent Claim
26 words
A single wavelength semiconductor laser according to claim 2, wherein said loss means comprises an absorptive region provided adjacent to or in said laser cavity means.
Claim 5
Dependent Claim
25 words
A single wavelength semiconductor laser according to claim 2, wherein said loss means comprises an antireflection coating provided on an end face of said laser.
Claim 6
Dependent Claim
30 words
A single wavelength semiconductor laser according to claim 2, wherein said loss means comprises an end face of said laser formed slantingly relative to a direction perpendicular to said waveguide.
Claim 7
Dependent Claim
37 words
A single wavelength semiconductor laser according to claim 1, wherein two waveguides are arranged to constitute an asymmetrical directional coupler, and the two modes are even and odd modes which are propagated through said asymmetrical directional coupler.
Claim 8
Dependent Claim
35 words
A single wavelength semiconductor laser according to claim 1, wherein said mode selector means comprises separator means for spatially separating the two laser resonance modes and taking out one of the two laser resonance modes.
Claim 9
Dependent Claim
61 words
A single wavelength semiconductor laser according to claim 7, wherein two waveguides are arranged to constitute an asymmetrical directional coupler, the two modes are even and odd modes which are propagated through said asymmetrical directional coupler, and said mode selector means comprises a waveguide which is connected to and extends from one of said two waveguides of said asymmetrical directional coupler.
Claim 10
Dependent Claim
36 words
A single wavelength semiconductor laser according to claim 1, wherein said waveguide comprises a multimode waveguide and the two modes are 0-th order transverse mode and first-order transverse mode which are propagated through said multimode waveguide.
Claim 11
Dependent Claim
23 words
A single wavelength semiconductor laser according to claim 9, wherein said mode selector means comprises a single mode waveguide having a predetermined cutoff.
Claim 12
Dependent Claim
33 words
A single wavelength semiconductor laser according to claim 1, wherein the two modes are transverse electric (TE) and transverse magnetic (TM) modes whose principal directions of electric fields are different from each other.
Claim 13
Dependent Claim
30 words
A single wavelength semiconductor laser according to claim 11, wherein said mode selector means comprises selective loss means for selectively imparting loss to one of the TE and TM modes.
Claim 14
Dependent Claim
18 words
A single wavelength semiconductor laser according to claim 12, wherein said mode selector means comprises a metal film.
Claim 15
Dependent Claim
23 words
A single wavelength semiconductor laser according to claim 11, wherein said laser cavity means comprises a magnetic semiconductor layer formed along said waveguide.
Claim 16
Dependent Claim
20 words
A single wavelength semiconductor laser according to claim 1, wherein said perturbation means comprises a grating formed along said waveguide.
Claim 17
Dependent Claim
25 words
A single wavelength semiconductor laser according to claim 1, wherein said mode selector means comprises an electrode for injecting current into said mode selector means.
Claim 18
Dependent Claim
136 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a multimode waveguide through which a plurality of transverse modes having different absolute values of propagation constants can be propagated, and means for imparting a periodical perturbation to said waveguide, so that the transverse modes can be coupled to each other when light of a predetermined wavelength is propagated in said waveguide, the two coupled transverse modes travelling forward and rearward along said waveguide to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 19
Dependent Claim
136 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a multimode waveguide through which a plurality of transverse modes having different absolute values of propagation constants can be propagated, and means for imparting a periodical perturbation to said waveguide, so that the transverse modes can be coupled to each other when light of a predetermined wavelength is propagated in said waveguide, the two coupled transverse modes travelling forward and rearward along said waveguide to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 20
Dependent Claim
133 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide, and means for imparting a periodical perturbation to said waveguide so that transverse electric (TE) and transverse magnetic (TM) modes having different absolute values of propagation constants can be coupled to each other, accompanied with a mode conversion, when light of a predetermined wavelength is propagated in said waveguide, the coupled TE and TM modes travelling forward and rearward to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 21
Dependent Claim
133 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide, and means for imparting a periodical perturbation to said waveguide so that transverse electric (TE) and transverse magnetic (TM) modes having different absolute values of propagation constants can be coupled to each other, accompanied with a mode conversion, when light of a predetermined wavelength is propagated in said waveguide, the coupled TE and TM modes travelling forward and rearward to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 22
Dependent Claim
121 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide and means for imparting a perturbation to said waveguide, so that two kinds of modes having different absolute values of propagation constants can be coupled to each other when light of a predetermined wavelength is propagated in said waveguide, the coupled modes respectively travelling in opposite directions to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 23
Dependent Claim
121 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide and means for imparting a perturbation to said waveguide, so that two kinds of modes having different absolute values of propagation constants can be coupled to each other when light of a predetermined wavelength is propagated in said waveguide, the coupled modes respectively travelling in opposite directions to constitute two degenerate laser resonance modes; and mode selector means for selectively outputting a predetermined laser resonance mode as one of the two degenerate laser resonance modes, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the other of the two degenerate laser resonance modes.
Claim 24
Dependent Claim
170 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide and means for imparting a perturbation to said waveguide, so that first and second modes having different absolute values of propagation constants can be coupled to each other when light of a predetermined wavelength is propagated in said waveguide, the coupled first and second modes respectively travelling in opposite first and second directions to constitute first and second laser resonance modes, the first laser resonance mode consisting of the first mode travelling in the first direction and the second mode travelling in the second direction, and second laser resonance mode consisting of the first mode travelling in the second direction and the second mode travelling in the first direction; and mode selector means for selectively outputting the first mode travelling in the first direction, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the the first mode travelling in the second direction.
Claim 25
Dependent Claim
170 words
A single wavelength semiconductor laser comprising: laser cavity means, said laser cavity means including a waveguide and means for imparting a perturbation to said waveguide, so that first and second modes having different absolute values of propagation constants can be coupled to each other when light of a predetermined wavelength is propagated in said waveguide, the coupled first and second modes respectively travelling in opposite first and second directions to constitute first and second laser resonance modes, the first laser resonance mode consisting of the first mode travelling in the first direction and the second mode travelling in the second direction, and second laser resonance mode consisting of the first mode travelling in the second direction and the second mode travelling in the first direction; and mode selector means for selectively outputting the first mode travelling in the first direction, said mode selector means being structured so that light returning to said semiconductor laser from outside can be coupled only to the the first mode travelling in the second direction.
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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) | 1998-08-21 | 1999-02-20 | 1999-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-21 | 2003-02-20 | 2003-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-21 | 2007-02-20 | 2007-08-22 | $7700.00 | Window Closed / Lapsed |