US5495548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photosensitization of optical fiber and silica waveguides
Assignee: Canada Minister of Communications
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Filing: 1994-02-16
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Granted: 1996-02-27
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Expires: 2014-02-16
Abstract
Abstract A method of fabricating a strongly photosensitive optical waveguide is comprised of locally heating at least a portion of a weakly photosensitive optical waveguide for a period of time sufficient to increase the density of defects associated with photosensitivity in the heated portion of the waveguide core.
Inventors
- 👤 Francois C. Bilodeau
- 👤 Bernard Y. Malo
- 👤 Jacques Albert
- 👤 Derwyn C. Johnson
- 👤 Kenneth O. Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:31
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/02057; G02B6/02076; G02B6/02114; G02B6/10
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
54 words
A method of fabricating a strongly photosensitive optical waveguide comprising locally heating while maintaining the structural integrity of a portion of a weakly photosensitive optical waveguide to an approximately white hot temperature for a period of time sufficient to increase the concentration of defects associated with photosensitivity in the heated portion of said waveguide.
Claim 2
Independent Claim
54 words
A method of fabricating a strongly photosensitive optical waveguide comprising locally heating while maintaining the structural integrity of a portion of a weakly photosensitive optical waveguide to an approximately white hot temperature for a period of time sufficient to increase the concentration of defects associated with photosensitivity in the heated portion of said waveguide.
Claim 3
Dependent Claim
15 words
A method as defined in claim 1 in which the waveguide is an optical fiber.
Claim 4
Dependent Claim
41 words
A method as defined in claim 2 in which said weakly photosensitive waveguide is comprised of one of Ge:SiO 2 on a Si substrate, Ge:SiO 2 on a SiO 2 substrate, and Ge:SiO 2 on a Al 2 O 3 substrate.
Claim 5
Dependent Claim
25 words
A method as defined in claim 2 in which said weakly photosensitive waveguide is comprised of silica doped with one of germanium, cerium and europium.
Claim 6
Dependent Claim
14 words
A method as defined in claim 4, wherein the waveguide is codoped with alumina.
Claim 7
Dependent Claim
14 words
A method as defined in claim 2, wherein the waveguide is codoped with alumina.
Claim 8
Dependent Claim
15 words
A method as defined in claim 1 in which the waveguide is a planar waveguide.
Claim 9
Dependent Claim
29 words
A method as defined in claim 7 in which said weakly photosensitive waveguide is comprised of one of germanium doped silica or a silicon, silica and sapphire substrate material.
Claim 10
Dependent Claim
36 words
A method as defined in claim 7, including the initial steps of fabricating the planar waveguide by flame hydrolysis of Ge doped SiO 2 on a silica substrate to form a layer approximately 5 μm thick.
Claim 11
Dependent Claim
25 words
A method as defined in claim 7 in which said weakly photosensitive waveguide is comprised of silica doped with one of germanium, cerium and europium.
Claim 12
Dependent Claim
14 words
A method as defined in claim 10, wherein the waveguide is codoped with alumina.
Claim 13
Dependent Claim
15 words
A method as defined in claim 1 in which said defects are oxygen deficiency defects.
Claim 14
Dependent Claim
21 words
A method as defined in claim 1 in which said waveguide is fabricated strongly photosensitive to wavelengths of approximately 248 nm.
Claim 15
Dependent Claim
37 words
A method as defined in claim 1 in which the weakly photosensitive optical waveguide local heating is conducted by moving a local heating source along said waveguide to increase a size of a region containing said defects.
Claim 16
Dependent Claim
29 words
A method as defined in claim 1 in which the local heating source is a flame, used to brush the optical waveguide, the flame being fueled by a gas.
Claim 17
Dependent Claim
18 words
A method as defined in claim 15 in which the temperature of the flame is approximately 1700° C.
Claim 18
Dependent Claim
18 words
A method as defined in claim 16 in which the flame brushing is continued for approximately 10-20 minutes.
Claim 19
Dependent Claim
15 words
A method as defined in claim 15 in which oxygen is added to the gas.
Claim 20
Dependent Claim
25 words
A method as defined in claim 1 in which said weakly photosensitive waveguide is comprised of silica doped with one of germanium, cerium and europium.
Claim 21
Dependent Claim
14 words
A method as defined in claim 19, wherein the waveguide is codoped with alumina.
Claim 22
Dependent Claim
76 words
A method as defined in claim 1 including the further steps of creating at least one of a Bragg and surface relief grating comprising positioning a grating phase mask at the side of the strongly photosensitized portion of the waveguide with its plane parallel to the axis of the waveguide, and irradiating said strongly photosensitized portion of the waveguide through the phase mask with monochromatic light at a wavelength at which said waveguide is strongly photosensitive.
Claim 23
Dependent Claim
26 words
A method as defined in claim 1 in which said weakly photosensitive waveguide is comprised of silica doped with one of germanium, cerium, europium and phosphorous.
Claim 24
Dependent Claim
27 words
A method as defined in claim 22 in which the waveguide is one of an optical fiber, a channel and at least part of a planar layer.
Claim 25
Dependent Claim
29 words
A method as described in claim 1, in which the heating step is comprised of placing the weakly photosensitive optical waveguide in a flame fueled by hydrogen or deuterium.
Claim 26
Independent Claim
50 words
A method of fabricating a strongly photosensitive waveguide comprising heating a weakly photosensitive optical waveguide to an approximately white hot temperature in a high pressure plasma of hydrogen or deuterium gas for a period of time sufficient to increase the concentration of defects associated with photosensitivity in the heated waveguide.
Claim 27
Independent Claim
50 words
A method of fabricating a strongly photosensitive waveguide comprising heating a weakly photosensitive optical waveguide to an approximately white hot temperature in a high pressure plasma of hydrogen or deuterium gas for a period of time sufficient to increase the concentration of defects associated with photosensitivity in the heated waveguide.
Claim 28
Independent Claim
74 words
A method of photosensitization comprising locally heating while maintaining the structural integrity of at least a portion of a weakly photosensitive silica optical waveguide doped with phosphorous to an approximately white hot temperature for a period of time sufficient to increase the concentration of defects associated with photosensitivity in the heated portion of the waveguide and irradiating said heated portion with actinic radiation in order to cause a refractive index change in the waveguide.
Claim 29
Independent Claim
74 words
A method of photosensitization comprising locally heating while maintaining the structural integrity of at least a portion of a weakly photosensitive silica optical waveguide doped with phosphorous to an approximately white hot temperature for a period of time sufficient to increase the concentration of defects associated with photosensitivity in the heated portion of the waveguide and irradiating said heated portion with actinic radiation in order to cause a refractive index change in the waveguide.
Claim 30
Dependent Claim
33 words
A method as defined in claim 26 in which a waveguide core is covered by a cladding essentially transparent to active radiation, and passing said radiation through the cladding to the waveguide core.
Claim 31
Dependent Claim
28 words
A method as defined in claim 27 in which the heating step is comprised of retaining said weakly sensitive waveguide in a plasma fueled by hydrogen or deuterium.
Claim 32
Dependent Claim
22 words
A method as defined in claim 26 in which the waveguide core is codoped with a laser active dopant such as erbium.
References Cited (Backward Citations)
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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) | 1999-02-26 | 1999-08-28 | 2000-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-26 | 2003-08-28 | 2004-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-26 | 2007-08-28 | 2008-02-27 | $7700.00 | Window Closed / Lapsed |