US6174748B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming a tapered section in a semiconductor device to provide for reproducible mode profile of the output beam
Assignee: Viavi Solutions Inc
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Filing: 2000-02-11
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Granted: 2001-01-16
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Expires: 2020-02-11
Abstract
Abstract A method for fabricating a high power laser diode device with an output emission with a nearly circular mode profile for efficient coupling into an optical fiber. A vertical taper waveguide and a window tolerance region are formed in a base structure of the device employing successive etching steps. Further regrowth completes the device structure. The resultant laser device has a vertical and lateral tapered waveguide that adiabatically transforms the highly elliptical mode profile in an active gain section of the device into a substantially circular mode profile in a passive waveguide section of the device.
Inventors
- 👤 Heonsu Jeon
- 👤 Jean-Marc Verdiell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:54
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/16; H01S5/164; G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/1228; H01S5/1003; H01S5/1014; Y; Y10; Y10S; Y10S438/00; Y10S438/942
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
109 words
A method of fabricating a laser diode device, comprising the steps of: forming a base structure comprising a plurality of semiconductor layers having a waveguide region that includes an active waveguide layer; performing a first etching on the base structure forming a vertical taper contour along the base structure including a portion of the active waveguide layer; and performing a second etching producing a planar waveguide region with a flat portion adjacent to the formed vertical taper of the first performed etching, the planar region providing a window region of a length within which a cleave can be performed to form a facet upon further completion of the device.
Claim 2
Independent Claim
109 words
A method of fabricating a laser diode device, comprising the steps of: forming a base structure comprising a plurality of semiconductor layers having a waveguide region that includes an active waveguide layer; performing a first etching on the base structure forming a vertical taper contour along the base structure including a portion of the active waveguide layer; and performing a second etching producing a planar waveguide region with a flat portion adjacent to the formed vertical taper of the first performed etching, the planar region providing a window region of a length within which a cleave can be performed to form a facet upon further completion of the device.
Claim 3
Dependent Claim
36 words
The method of claim 1 wherein the waveguide region includes a passive waveguide layer formed beneath the active waveguide layer, a further step comprising: forming a stop etch layer between the passive and active waveguide layers.
Claim 4
Dependent Claim
20 words
The method of claim 2 wherein the active and passive waveguide layers comprise InGaAsP and the etch-stop layer is InP.
Claim 5
Dependent Claim
35 words
The method of claim 1 comprising the further step of: forming a sacrificial layer over the base structure, the thickness of the sacrificial layer determinative of the depth of etching in the first performed etching.
Claim 6
Dependent Claim
79 words
The method of claim 4 comprising the further step of: determining a thickness of the sacrificial layer, d sac , according to the relationship, r min ·t<d sac <r max ·t−d taper where r min and r max respectively correspond to minimum and maximum etch rates along a direction of the vertical, t corresponds to total etching duration time, and d taper corresponds to a total thickness of the plurality of layers through which a vertical taper is formed.
Claim 7
Dependent Claim
14 words
The method of claim 1 wherein the first performed etching is a non-selective etching.
Claim 8
Dependent Claim
22 words
The method of claim 6 wherein said non-selective etching is a diffusion limited wet etching employing a bromine (Br 2 )-based etchant.
Claim 9
Dependent Claim
22 words
The method of claim 1 wherein the first performed etching is applied via a masking layer having a tapered opening formed therein.
Claim 10
Dependent Claim
14 words
The method of claim 1 wherein the second performed etching is a selective etching.
Claim 11
Dependent Claim
12 words
The method of claim 9 wherein the selective etching comprises InGaAsP-based etchant.
Claim 12
Dependent Claim
50 words
The method of claim 1 further comprising the step of: forming a stop etch layer between the active waveguide layer and layer therebeneath, the second performed etching further etching the active waveguide layer to the stop etch layer revealing a portion thereof, the length of which is the window region.
Claim 13
Dependent Claim
24 words
The method of claim 11 wherein the layer beneath the stop etch layer is a passive waveguide layer forming part of the waveguide region.
Claim 14
Dependent Claim
141 words
The method of claim 1 further comprising the steps of: forming a first stop etch layer between the active waveguide layer and layer therebeneath utilized during the second performed etching; forming multiple sacrificial layers over the base structure, one of said multiple sacrificial layers having a thickness determinative of the depth of etch performed by the first performed etching and another of said multiple sacrificial layers for providing a second etch-stop layer utilized during the second etching; said second etching further comprising the steps of: performing a first selective etching step for removing exposed portions of the first and second etch-stop layers exposed during the first performed etching; and performing a second selective etching step for further etching the active waveguide layer to uncover a further portion of the first stop etch layer, the length of which is the window region.
Claim 15
Dependent Claim
24 words
The method of claim 13 wherein said first selective etching step forms a eye-mark for easy identification of one end of said window region.
Claim 16
Dependent Claim
26 words
The method of claim 13 wherein the waveguide region and the one multiple sacrificial layer are InGaAsP and the first and second etch-stop layers are InP.
Claim 17
Dependent Claim
39 words
The method of claim 15 wherein the non-selective etching is a diffusion limited wet etching employing a bromine (Br 2 )-based etchant, the first selective etching step is InP-based etchant and the second selective etching step is InGaAsP-based etchant.
Claim 18
Dependent Claim
22 words
The method of claim 13 wherein the first performed etching is applied via a masking layer having a tapered opening formed therein.
Claim 19
Dependent Claim
26 words
The method of claim 13 wherein the first performed etching is a diffusion-limited etching step applied through a masking layer having a tapered opening formed therein.
Claim 20
Dependent Claim
61 words
The method of claim 1 wherein the waveguide region includes a passive waveguide layer formed beneath the active waveguide layer, a further comprising the step of: forming the thickness of the passive waveguide layer to correspond to a desired resulting mode profile based upon adiabatic transformation of a mode propagating from the tapered active waveguide layer into the passive waveguide layer.
Claim 21
Dependent Claim
15 words
The method of claim 19 wherein said desired adiabatic transformed mode profile is substantially circular.
Claim 22
Dependent Claim
59 words
The method of claim 1 further comprising the step s of: forming a transparent waveguide layer on the waveguide region as part of the base structure after performance of the etching steps; and forming a grating in the transparent waveguide layer upon completion of the first and second performed etching over a remaining portion of the active waveguide layer.
Claim 23
Dependent Claim
28 words
The method of claim 21 further comprising the steps of: forming a cladding layer on the transparent waveguide layer; and forming a contact layer of the cladding layer.
Claim 24
Dependent Claim
59 words
The method of claim 1 further comprising the steps of: forming a transparent waveguide layer on the waveguide region as part of the base structure prior to performance of the etching steps; and forming a grating in the transparent waveguide layer upon completion of the first and second performed etching over a remaining portion of the active waveguide layer.
Claim 25
Dependent Claim
28 words
The method of claim 23 further comprising the steps of: forming a cladding layer on the transparent waveguide layer; and forming a contact layer of the cladding layer.
Claim 26
Dependent Claim
41 words
The method of claim 1 further comprising a regowth process after completion of the first and second performed etching comprising the steps of: forming a cladding layer on the etched base structure; and forming a contact layer of the cladding layer.
Claim 27
Dependent Claim
31 words
The method of claim 25 further comprising the step of: forming a lateral taper region in the cladding layer spatially coincident with the formed vertical taper of the active waveguide layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-01-16 | 2004-07-17 | 2005-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-01-16 | 2008-07-17 | 2009-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-01-16 | 2012-07-17 | 2013-01-16 | $7700.00 | Window Closed / Lapsed |