Patent US4019556A successfully refreshed from Google Patents.
Patent EP0595080A1 successfully refreshed from Google Patents.
EP0595080A1
Expired / Lapsed
EP
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Low-loss strip-loaded optical waveguide
Assignee: International Business Machines Corp
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Filing: 1993-10-06
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Granted: —
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Expires: 2013-10-06
Abstract
Abstract An optical waveguide is described incorporating a semiconductor substrate, a layer of silicon formed thereover, a layer of Si 1- x Ge x or Si 1- x - y Ge x C y formed thereover for carrying optical radiation, and a layer of silicon or other material having a different index of refraction formed over the layer for carrying the radiation and is patterned to define the waveguide below thick areas and patterned to have thin areas elsewhere to provide a capping layer. The invention overcomes the problem of attenuation due to sidewall surfaces and interfaces normally used to define the lateral dimension of the waveguide.
Inventors
- 👤 Jean-Marc Halbout
- 👤 Subramanian Srikanteswara Iyer
- 👤 Vijay Panchapa Kesan
- 👤 George Victor Treyz
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 21:44
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/13; G02B6/132; G02B6/122; G02B6/134; G02B6/1347
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
98 words
A waveguide (10) for carrying optical radiation comprising: a substrate (12), a first layer (18) of silicon formed over said substrate (12), a second layer (22) of a material selected from the group consisting of Si 1- x Ge x and Si 1- x - y Ge x C y formed over said first layer of silicon (18), and a third layer (26) of material formed over said second layer (22) having a first thickness in first areas (29) where said waveguide (10) is desired and a second thickness in second areas (30) where no waveguide is desired.
Claim 2
Dependent Claim
25 words
The waveguide of claim 1, wherein said first layer (18) is an epitaxial layer having a thickness in the range from 10 nm to 5µm.
Claim 3
Dependent Claim
50 words
The waveguide of claim 1 or 2, wherein said second thickness in second areas (30) of said third layer (26) is in the range from 10 - 40 nm and wherein said first thickness in said first areas (29) of said third layer (26) is in the range from 3-5µm.
Claim 4
Dependent Claim
65 words
The waveguide of any of the preceding claims 1 to 3, wherein said second layer (22) has a thickness in the range from 2.8-4.2µm or in the range from 100 nm to 50µm and wherein the mole fraction x of germanium in said material of said second layer (22) is in the range from .012 to .018 or in the range from 0.01 to 0.90.
Claim 5
Dependent Claim
43 words
The waveguide of any of the preceding claims 1 to 4, wherein said substrate (12) includes a fourth layer (14) of SiO ₂ and a fifth layer (16) of single crystalline Si on its upper surface (17) and below said first layer (18).
Claim 6
Dependent Claim
56 words
The waveguide of any of the preceding claims 1 to 5, wherein said first areas (29) of said third layer (26) has a width in the range from 5 to 20µm or in the range from 15 to 200 µm and wherein said second layer (22) has a width in the range from 5 to 200µm.
Claim 7
Dependent Claim
55 words
The waveguide of any of the preceding claims 1 to 6, wherein said third layer (26) is selected from the group consisting of silicon, SiO ₂, Si 1 -x Ge x and Si 1- x - y Ge x C y so long as the material has a different composition than said second layer (22).
Claim 8
Independent Claim
127 words
A method for fabricating an optical waveguide (10) comprising the steps of: selecting a substrate (12), forming a first layer (18) of silicon over said substrate (12), forming a second layer (22) of material, said material selected from the group consisting of Si 1- x Ge x , and Si 1- x - y Ge x C y over said first layer of silicon, forming a third layer (26) of material over said second layer (22) having an index of refraction different from the index of refraction of said second layer (22), and patterning said third layer (26) to form first areas (29) having a first thickness where said waveguide (10) is desired and forming second areas (30) having a second thickness where no waveguide is desired.
Claim 9
Dependent Claim
33 words
The method of claim 8, wherein said step of forming said first layer (18) includes the step of forming an epitaxial layer having a thickness in the range from 10 nm to 5µm..
Claim 10
Dependent Claim
59 words
The method of claim 9, wherein said step of patterning said third layer (26) includes a first thickness in said first areas (29) in the range from 3-5µm and wherein said first areas (29) of said third layer (26) have a width in the range from 5 to 20 µm or in the range from 15 to 200 µm.
Claim 11
Independent Claim
62 words
The method of any of the preceding claims 8 to 10, wherein said step of forming a second layer (22) includes selecting the mole fraction x of germanium in the range from .012 to .018 or in the range from 0.01 to 0.90 and further includes forming said second layer (22) having a width in the range from 5 - 200 µm.
Claim 12
Independent Claim
41 words
The method of any of the preceding claims 8 to 11, wherein said step of selecting said substrate (12) includes a substrate having a fourth layer (14) of SiO₂ and a fifth layer (16) of Si on its upper surface (17).
References Cited (Backward Citations)
US5109464A
Cited
US5107538A
Cited
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