Patent US4764929A successfully refreshed from Google Patents.
US4764929A
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US
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Semiconductor laser array apparatus with adjustable phase plate
Assignee: Northrop Grumman Corp
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Filing: 1986-10-30
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Granted: 1988-08-16
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Expires: 2006-10-30
Abstract
Abstract A phase-locked semiconductor laser array in which the phase of oscillation of alternate laser elements is adjusted externally to the laser cavity. A phase plate having parallel ribs of tapered thickness is positioned in close proximity to the emitting facet of a laser array, and is adjusted in position until the ribs are registered with alternate laser elements, and the thickness presented to the emitted laser beams is sufficient to cause a phase change of 180 degrees. After light from the array has passed through the phase plate, the entire set of beams is in phase and produces a practically single-lobed far-field pattern.
Inventors
- 👤 Suwat Thaniyavarn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:04
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/40; H01S5/4025; H01S5/4031; H01S5/4081
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
Semiconductor laser array apparatus comprising: an array of semiconductor lasers having an emitting facet, the array having a simple geometry favoring oscillation in the antisymmetric array mode; a phase plate having a plurality of elements of which the spacing matches alternate laser elements in the array, wherein the phase plate includes a plurality of parallel ribs of tapering thickness, whereby the array can be conveniently adjusted by moving the phase plate in a direction parallel to the ribs until the far-field pattern is optimized; and means for securing the phase plate in close proximity to the emitting facet, in registration with the laser elements, to provide a phase shift of 180 degrees to alternate elemental outputs from the array of lasers, whereby the far-field pattern of the array assumes the predominantly single-lobed configuration associated with in-phase laser arrays.
Claim 2
Dependent Claim
138 words
Semiconductor laser array apparatus comprising: an array of semiconductor lasers having an emitting facet, the array having a simple geometry favoring oscillation in the antisymmetric array mode; a phase plate having a plurality of elements of which the spacing matches alternate laser elements in the array, wherein the phase plate includes a plurality of parallel ribs of tapering thickness, whereby the array can be conveniently adjusted by moving the phase plate in a direction parallel to the ribs until the far-field pattern is optimized; and means for securing the phase plate in close proximity to the emitting facet, in registration with the laser elements, to provide a phase shift of 180 degrees to alternate elemental outputs from the array of lasers, whereby the far-field pattern of the array assumes the predominantly single-lobed configuration associated with in-phase laser arrays.
Claim 3
Dependent Claim
36 words
Semiconductor laser array apparatus as defined in claim 1, wherein: the phase plate includes a substrate of uniform-thickness material, such as glass; and the ribs are of dielectric material formed on the surface of the substrate.
Claim 4
Dependent Claim
21 words
Semiconductor laser array apparatus as defined in claim 1, wherein: the means for securing the phase plate includes an adhesive material.
Claim 5
Independent Claim
92 words
A method for assembling semiconductor laser array apparatus, comprising the steps of: forming a phase plate to include a plurality of parallel ribs of tapering thickness; positioning the phase plate in close proximity to an emitting facet of an array of laser elements; adjusting the position of the phase plate laterally to align the ribs with alternate laser elements; adjusting the position of the phase plate in a direction parallel with the ribs, to select a rib thickness providing the desired 180-degree phase shift to alternate beams emitted from the laser array.
Claim 6
Independent Claim
92 words
A method for assembling semiconductor laser array apparatus, comprising the steps of: forming a phase plate to include a plurality of parallel ribs of tapering thickness; positioning the phase plate in close proximity to an emitting facet of an array of laser elements; adjusting the position of the phase plate laterally to align the ribs with alternate laser elements; adjusting the position of the phase plate in a direction parallel with the ribs, to select a rib thickness providing the desired 180-degree phase shift to alternate beams emitted from the laser array.
Claim 7
Dependent Claim
50 words
A method as defined in claim 4, and further comprising the steps of: verifying the proper position of the phase plate by monitoring the far-field pattern; repeating the final adjusting step until the pattern becomes as near to a single-lobed one as possible and securing the phase plate in position.
References Cited (Backward Citations)
US3408596A
Cited
US4641311A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |