Patent US2918494A successfully refreshed from Google Patents.
US4547262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming thin film passive light waveguide circuit
Assignee: Unisys Corp
•
Filing: 1984-08-30
•
Granted: 1985-10-15
•
Expires: 2004-08-30
Abstract
Abstract A thin film passive integrated optical waveguide is formed in a lithium tantalate substrate by proton exchange in a benzoic acid bath. Annealing the substrate provides increased waveguide depth and stabilizes the refractive index. Optical components are formed by proton exchange of the masked substrate after formation of a planar waveguide.
Inventors
- 👤 William Spillman, Jr.
- 👤 Richard A. Soref
- 👤 Norman A. Sanford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:47
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/30; G02B6/10; G02B6/12; G02B6/12004; G02B6/13; G02B6/134; G02B6/1345; G02B2006/12083; G02B2006/12102; G02B2006/12114
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
159 words
A method for the formation of an optical component in a planar optical substrate having a predetermined index of refraction, comprising the steps of: providing a substrate comprised of LiTaO 3 , cleaving said substrate to provide a major planar surface along the x--y plane, forming a predetermined pattern of masking material on said major planar surface, said pattern exposing a limited surface area of said substrate, diffusing into said limited surface area by proton exchange a plurality of hydrogen ions in a quantity sufficient to effect an increase in a component of said refractive index in said area, thereby forming said optical component with an index profile having a predetermined planar pattern at said surface, a predetermined depth, and a first region of predetermined extraordinary index of refraction, and providing thermal energy to said substrate for a sufficient period of time to effect a predetermined reduction in said index component and a predetermined increase in said profile depth.
Claim 2
Independent Claim
159 words
A method for the formation of an optical component in a planar optical substrate having a predetermined index of refraction, comprising the steps of: providing a substrate comprised of LiTaO 3 , cleaving said substrate to provide a major planar surface along the x--y plane, forming a predetermined pattern of masking material on said major planar surface, said pattern exposing a limited surface area of said substrate, diffusing into said limited surface area by proton exchange a plurality of hydrogen ions in a quantity sufficient to effect an increase in a component of said refractive index in said area, thereby forming said optical component with an index profile having a predetermined planar pattern at said surface, a predetermined depth, and a first region of predetermined extraordinary index of refraction, and providing thermal energy to said substrate for a sufficient period of time to effect a predetermined reduction in said index component and a predetermined increase in said profile depth.
Claim 3
Dependent Claim
29 words
The method as set forth in claim 1, wherein said proton exchange is provided by immersion of said substrate in a heated acid bath for a predetermined time period.
Claim 4
Dependent Claim
25 words
The method as set forth in claim 1, wherein said masking material is selected from the group consisting of alloys of chromium, gold or aluminum.
Claim 5
Dependent Claim
18 words
The method as set forth in claim 1, wherein said masking material is comprised of a nonconductive dielectric.
Claim 6
Dependent Claim
19 words
The method as set forth in claim 5, wherein said masking material is comprised of an oxide of silicon.
Claim 7
Dependent Claim
15 words
The method as set forth in claim 2, wherein said acid bath comprises benzoic acid.
Claim 8
Dependent Claim
16 words
The method of claim 6, wherein said bath is heated between 122° C. and 249° C.
Claim 9
Dependent Claim
17 words
The method as set forth in claim 7, wherein said predetermined time period is about 2 hours.
Claim 10
Dependent Claim
18 words
The method as set forth in claim 8, wherein said acid bath is heated to about 249° C.
Claim 11
Dependent Claim
24 words
The method as set forth in claim 9, wherein said thermal energy comprises annealing said substrate at about 250° C. for about 18 hours.
Claim 12
Dependent Claim
24 words
The method as set forth in claim 10, comprising the additional step of annealing said substrate for about 17 hours at about 325° C.
Claim 13
Independent Claim
170 words
A method for forming an integrated light waveguide circuit in an optical substrate having a first index of refraction, comprising the steps of: providing a substrate of LiTaO 3 , cleaving said substrate to provide a major planar surface along an x--y plane, exposing said major surface to an acid bath for a first predetermined time period at a first predetermined temperature, annealing said substrate for a second predetermined time period at a second predetermined temperature to form a planar region having a second index of refraction greater than said first index of refraction and a predetermined depth. forming an etch resistant mask and selectively patterning said major surface to define regions of predetermined optical geometry, and exposing said major surface to said acid bath for a third predetermined time period exceeding said first predetermined time period, said third period being of sufficient duration to provide said regions of predetermined optical geometry with a third refractive index and a depth substantially equal to said predetermined depth of said planar region.
Claim 14
Independent Claim
170 words
A method for forming an integrated light waveguide circuit in an optical substrate having a first index of refraction, comprising the steps of: providing a substrate of LiTaO 3 , cleaving said substrate to provide a major planar surface along an x--y plane, exposing said major surface to an acid bath for a first predetermined time period at a first predetermined temperature, annealing said substrate for a second predetermined time period at a second predetermined temperature to form a planar region having a second index of refraction greater than said first index of refraction and a predetermined depth. forming an etch resistant mask and selectively patterning said major surface to define regions of predetermined optical geometry, and exposing said major surface to said acid bath for a third predetermined time period exceeding said first predetermined time period, said third period being of sufficient duration to provide said regions of predetermined optical geometry with a third refractive index and a depth substantially equal to said predetermined depth of said planar region.
Claim 15
Dependent Claim
66 words
The method as set forth in claim 12, wherein said acid bath is comprised of benzoic acid, said first predetermined temperature is about 249° C., said first predetermined time period is less than about 2 hours, said second predetermined time period is at least 18 hours, said second predetermined temperature is about 249° C., and said third predetermined time period is greater than about 5 hours.
References Cited (Backward Citations)
US4115150A
Cited
US4087315A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |