Patent US6231771B1 successfully refreshed from Google Patents.
US6231771B1
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Process for making optical waveguides
Assignee: Lumentum Technology UK Ltd
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Filing: 1999-04-05
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Granted: 2001-05-15
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Expires: 2019-04-05
Abstract
Abstract A process for treating a waveguide structure which comprises a silicon substrate with an integrally formed rib waveguide is described. The waveguide has an end portion with a facet, the end portion overhanging the silicon substrate and having an oxide layer on its underside protruding from the facet of the waveguide. A nitride layer extends over the upper surface of the waveguide and the facet. The treatment process involves etching the oxide layer from the underside, growing a new oxide layer, etching the nitride layer and then depositing a new nitride layer.
Inventors
- 👤 John Paul Drake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:37
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/13; G02B6/131; G02B6/122; G02B6/24; G02B6/26; G02B6/30; G02B2006/12083; G02B2006/12097; G02B2006/12166; G02B2006/12176
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
148 words
A process for treating a waveguide structure comprising: a silicon substrate with an integrally formed rib waveguide, the waveguide comprising an end portion with a facet, the end portion overhanging the silicon substrate and having an oxide layer on its underside protruding from the facet of the waveguide, and a nitride layer extending over the upper surface of the waveguide and the facet, the process comprising: i) carrying out an oxide etch step to remove the oxide layer from the underside; ii) carrying out an oxide growth step to form a new oxide layer on exposed silicon on the underside, said new oxide layer terminating at the facet; iii) carrying out a nitride etch step to remove the nitride layer; and iv) depositing a new nitride layer extending over the upper surface and facet without protruding beyond the facet, such that silicon nitride is formed on the facet.
Claim 2
Dependent Claim
148 words
A process for treating a waveguide structure comprising: a silicon substrate with an integrally formed rib waveguide, the waveguide comprising an end portion with a facet, the end portion overhanging the silicon substrate and having an oxide layer on its underside protruding from the facet of the waveguide, and a nitride layer extending over the upper surface of the waveguide and the facet, the process comprising: i) carrying out an oxide etch step to remove the oxide layer from the underside; ii) carrying out an oxide growth step to form a new oxide layer on exposed silicon on the underside, said new oxide layer terminating at the facet; iii) carrying out a nitride etch step to remove the nitride layer; and iv) depositing a new nitride layer extending over the upper surface and facet without protruding beyond the facet, such that silicon nitride is formed on the facet.
Claim 3
Dependent Claim
38 words
A process according to claim 1 , wherein the waveguide structure comprises an unwanted layer of oxide on the facet and wherein the process comprises an additional step (v) after step (iii) of removing the unwanted oxide layer.
Claim 4
Dependent Claim
15 words
A process according to claim 1 , wherein step (iv) is a blanket deposition step.
Claim 5
Dependent Claim
25 words
A process according to claim 1 , wherein the thickness of the new nitride layer is controlled to control the optical properties of the facet.
Claim 6
Dependent Claim
141 words
A process for making a waveguide structure in a silicon-on-insulator wafer comprising a silicon substrate, a layer of oxide on top of the silicon substrate and a layer of epitaxial silicon on top of the layer of oxide, the process comprising: defining a rib waveguide in the epitaxial layer; etching through the epitaxial layer on either side of the rib waveguide at an end portion thereof to expose the buried oxide layer; depositing oxide and nitride layers successively on the rib waveguide; undercutting the end portion to form a V-groove in the silicon substrate for aligning an optical fibre to the waveguide structure, said undercutting step leaving an unwanted part of the buried oxide layer extending beyond an end facet of the rib waveguide; and treating the waveguide structure by a process as defined hereinabove in accordance with claim 1 .
Claim 7
Dependent Claim
38 words
A process according to claim 2 , wherein the waveguide structure comprises an unwanted layer of oxide on the facet and wherein the process comprises an additional step (v) after step (iii) of removing the unwanted oxide layer.
Claim 8
Dependent Claim
15 words
A process according to claim 3 , wherein step (iv) is a blanket deposition step.
Claim 9
Dependent Claim
25 words
A process according to claim 4 , wherein the thickness of the new nitride layer is controlled to control the optical properties of the facet.
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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) | 2004-05-14 | 2004-11-13 | 2005-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-14 | 2008-11-13 | 2009-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-14 | 2012-11-13 | 2013-05-15 | $7700.00 | Window Closed / Lapsed |