US4738511A
Expired / Lapsed
US
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Molecular bonded fiber optic couplers and method of fabrication
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1986-01-07
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Granted: 1988-04-19
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Expires: 2006-01-07
Abstract
Abstract A fiber optic coupler is formed by heating juxtaposed optically flat surfaces formed on two lengths of optical fiber to the glass transition temperature. The fibers bond together while preserving the molecular composition of the fibers at bonded region. Depending upon the depth to which the fibers are lapped to form the optically flat surfaces, the coupler may be either an evanescent field coupler or a core intercept coupler. The fibers may be mounted on curved substrates and then lapped to form the optically flat surfaces. The optical throughput of a fiber may be monitored during assembly of a coupler to permit adjustment of the positions of the optically flat surfaces to produce a desired coupling efficiency. The fibers may then be bonded together by application of energy from a suitable coherent light source such as a CO 2 laser.
Inventors
- 👤 John J. Fling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:52
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2821; G02B6/2826; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
105 words
A fiber optic coupler for coupling an optical wave between a pair of optical fibers each having a central core surrounded by a cladding, the cores and claddings having characteristic refractive indices, comprising: a first planar surface formed on a first optical fiber by removing at least a portion of the cladding therefrom; a second planar surface formed on a second optical fiber by removing at least a portion of the cladding therefrom, said first and second planar surfaces being juxtaposed to form an interaction region wherein light propagates between the fibers; and said first and second planar surfaces being joined by a molecular bond.
Claim 2
Dependent Claim
105 words
A fiber optic coupler for coupling an optical wave between a pair of optical fibers each having a central core surrounded by a cladding, the cores and claddings having characteristic refractive indices, comprising: a first planar surface formed on a first optical fiber by removing at least a portion of the cladding therefrom; a second planar surface formed on a second optical fiber by removing at least a portion of the cladding therefrom, said first and second planar surfaces being juxtaposed to form an interaction region wherein light propagates between the fibers; and said first and second planar surfaces being joined by a molecular bond.
Claim 3
Dependent Claim
27 words
The fiber optic coupler of claim 1 wherein said coherent molecular bond is formed without altering the characteristic core and cladding refractive indices at the interaction region.
Claim 4
Dependent Claim
56 words
The fiber optic coupler of claim 2 wherein the planar surfaces are formed by removing only portions of the cladding from curved lengths of the optical fibers such that evanescent field coupling at the interaction region between optical waves guided by a first one of the fibers and the other fiber couples energy between the fibers.
Claim 5
Dependent Claim
43 words
The fiber optic coupler of claim 2 wherein the planar surfaces are formed by removing portions of the cladding and a portions of the core from curved lengths of the optical fibers such that juxtaposing the fiber cores forms an intercepting core coupler.
Claim 6
Dependent Claim
19 words
The fiber optic coupler of claim 2 wherein the interaction region is formed to provide a predetermined coupling efficiency.
Claim 7
Dependent Claim
39 words
The fiber optic coupler of claim 1 wherein said coherent molecular bond is formed by lapping the first and second planar surfaces to be optically flat and bonding them together by application of a controlled amount of energy thereto.
Claim 8
Dependent Claim
34 words
The fiber optic coupler of claim 6 wherein a compressive force is applied to said first and second fibers to apply pressure between said first and second planar surfaces as they are bonded together.
Claim 9
Independent Claim
115 words
A method for forming a fiber optic coupler for coupling an optical wave between a pair of optical fibers each having a central core surrounded by a cladding, the cores and claddings having characteristic refractive indices, comprising the steps of: forming a first planar surface formed on a first optical fiber by removing at least a portion of the cladding therefrom; forming a second planar surface formed on a second optical fiber by removing at least a portion of the cladding therefrom, said first and second planar surfaces being juxtaposed to form an interaction region wherein light propagates between the fibers; and forming a coherent molecular bond formed between the first and second planar surfaces.
Claim 10
Independent Claim
115 words
A method for forming a fiber optic coupler for coupling an optical wave between a pair of optical fibers each having a central core surrounded by a cladding, the cores and claddings having characteristic refractive indices, comprising the steps of: forming a first planar surface formed on a first optical fiber by removing at least a portion of the cladding therefrom; forming a second planar surface formed on a second optical fiber by removing at least a portion of the cladding therefrom, said first and second planar surfaces being juxtaposed to form an interaction region wherein light propagates between the fibers; and forming a coherent molecular bond formed between the first and second planar surfaces.
Claim 11
Dependent Claim
43 words
The method of claim 8 wherein the step of forming the coherent molecular bond comprises the steps of: aligning the planar surfaces relative to one another to provide a predetermined coupling efficiency; and applying energy to the planar surfaces to bond them together.
Claim 12
Dependent Claim
61 words
The method of claim 9 wherein the step of aligning the planar surfaces includes the steps of: introducing an optical beam into a first end of one of the fibers on one side of the interaction region; and monitoring the optical energy output from an end of at least one of the fibers on the other side of the interaction region.
Claim 13
Dependent Claim
23 words
The method of claim 9 wherein the step of applying energy to the planar surfaces includes focusing a beam of coherent light thereon.
Claim 14
Dependent Claim
26 words
The method of claim 8 wherein forming a coherent molecular bond includes heating the fibers to a transition temperature below the melting temperature of the fibers.
Claim 15
Dependent Claim
36 words
The method of claim 8, further including the step of applying a compressive force is to the first and second fibers to apply pressure between the first and second planar surfaces as they are bonded together.
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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) | 1991-04-19 | 1991-10-19 | 1992-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-19 | 1995-10-19 | 1996-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-19 | 1999-10-19 | 2000-04-19 | $7700.00 | Window Closed / Lapsed |