US5367588A
Expired / Lapsed
US
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Method of fabricating Bragg gratings using a silica glass phase grating mask and mask used by same
Assignee: Canada Minister of Communications
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Filing: 1992-10-29
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Granted: 1994-11-22
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Expires: 2012-10-29
Abstract
Abstract An index grating is imprinted in the core of an optical fiber using a specially designed silica glass phase grating mask. The phase mask is held in close proximity to the optical fiber. Laser irradiation of the phase mask with ultraviolet light at normal incidence imprints (photoinduces) into the optical fiber core the interference pattern created by the phase mask.
Inventors
- 👤 Kenneth O. Hill
- 👤 Bernard Y. Malo
- 👤 Francois C. Bilodeau
- 👤 Derwyn C. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:52
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70283; G02; G02B; G02B6/00; G02B6/02; G02B6/02057; G02B6/02076; G02B6/02123; G02B6/02133; G02B6/02138; G02B6/10; G02B6/14; G03F7/0005; G03F7/001; G03F7/7035; G02B6/0208; G02B6/02085; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
42 words
A method of fabricating Bragg gratings in the interior of an optical waveguide comprising disposing a silica glass phase grating mask adjacent and parallel to a photosensitive optical waveguide and applying a single collimating light beam through the mask to said medium.
Claim 2
Independent Claim
42 words
A method of fabricating Bragg gratings in the interior of an optical waveguide comprising disposing a silica glass phase grating mask adjacent and parallel to a photosensitive optical waveguide and applying a single collimating light beam through the mask to said medium.
Claim 3
Dependent Claim
77 words
A method as defined in claim 1 in which the mask has a surface relief pattern selected to modulate by approximately π+2 πn radians the phase of the light beam, wherein ##EQU3## where A is the amplitude of the surface relief pattern, n=0,1,2,3, λ is the wavelength of the light used for writing (photoinducing) an index change in the optical medium and n silica is the refractive index of the silica used in the mask at λ.
Claim 4
Dependent Claim
18 words
A method as defined in claim 2 in which the surface relief pattern in cross-section is a square-wave.
Claim 5
Dependent Claim
19 words
A method as defined in claim 2 in which the surface relief pattern in cross-section is a sine wave.
Claim 6
Dependent Claim
17 words
A method as defined in claim 1 in which the light beam is an ultraviolet light beam.
Claim 7
Dependent Claim
16 words
A method as defined in claim 5 in which the light beam is a laser beam.
Claim 8
Dependent Claim
19 words
A method as defined in claim 1 in which the light beam is provided by a KrF excimer laser.
Claim 9
Dependent Claim
16 words
A method as defined in claim 1 in which the optical medium is an optical fiber.
Claim 10
Dependent Claim
28 words
A method as defined in claim 8 in which striations of the phase mask grating are oriented orthogonal to or nearly orthogonal to the axis of the fiber.
Claim 11
Dependent Claim
26 words
A method as defined in claim 8 in which striations of the phase mask grating are oriented at an angle to the axis of the fiber.
Claim 12
Dependent Claim
19 words
A method as defined in claim 9 in which the light beam is provided by a KrF excimer laser.
Claim 13
Dependent Claim
69 words
A method as defined in claim 11 in which the mask has a surface relief pattern selected to modulate by approximately π+2 πn n=0,1,2,3, radians the phase of the light beam, wherein ##EQU4## n=0,1,2,3 where A is the amplitude of the surface relief pattern, λ is the wavelength of the light and n silica is the refractive index of the silica material used to make the mask at λ.
Claim 14
Dependent Claim
18 words
A method as defined in claim 12 in which the surface relief pattern in cross-section is a square-wave.
Claim 15
Dependent Claim
27 words
A method as defined in claim 13, in which a large dimension of the light beam cross-section is oriented parallel to striations of the phase mask grating.
Claim 16
Dependent Claim
13 words
A method as defined in claim 8 in which the striations are chirped.
Claim 17
Dependent Claim
13 words
A method as defined in claim 9 in which the striations are chirped.
Claim 18
Dependent Claim
25 words
A method as defined in claim 9 in which the phase mask contains variations in either or both of pitch and amplitude of the striations.
Claim 19
Dependent Claim
16 words
A method as defined in claim 11 in which the light beam is an ultraviolet beam.
Claim 20
Dependent Claim
25 words
A method as defined in claim 1 including locating a refracting lens between the mask and the optical medium prior to applying the light beam.
Claim 21
Dependent Claim
31 words
A method as defined in claim 19 including placing an opaque blocking means for the zero order light beam between the mask and the lens prior to applying the light beam.
Claim 22
Dependent Claim
32 words
A method as defined in claim 19 including placing opaque blocking means for the zero and second order light beams between the mask and the lens prior to applying the light beam.
Claim 23
Dependent Claim
26 words
A method as defined in claim 1 further including a spatial amplitude light filter for shaping the beam profile prior to passing through the phase grating.
Claim 24
Dependent Claim
27 words
A method as defined in claim 22 in which the filter is coated on a face of the mask opposite to a face containing the phase grating.
Claim 25
Dependent Claim
51 words
A method as defined in claim 2, then repeatedly moving one of the mask and medium relative to the other a distance corresponding to the fringe pattern and applying said collimating light beam through the mask to said medium, such that subsequent photoimprinted gratings reflect in phase with previously photoimprinted gratings.
Claim 26
Dependent Claim
36 words
A grating mask comprising a slab of silica glass having parallel corrugations on a surface thereof forming a surface relief pattern, the pattern containing variations in at least one of pitch and amplitude of the corrugations.
Claim 27
Dependent Claim
36 words
A grating mask comprising a slab of silica glass having parallel corrugations on a surface thereof forming a surface relief pattern, the pattern containing variations in at least one of pitch and amplitude of the corrugations.
Claim 28
Dependent Claim
41 words
A grating means comprising a slab of silica glass having parallel corrugations on a surface thereof forming a surface relief pattern, including a spacial amplitude light filter coated on a surface of the slab opposite to the surface carrying said pattern.
Claim 29
Dependent Claim
41 words
A grating means comprising a slab of silica glass having parallel corrugations on a surface thereof forming a surface relief pattern, including a spacial amplitude light filter coated on a surface of the slab opposite to the surface carrying said pattern.
Claim 30
Dependent Claim
28 words
A grating as defined in claim 25 further including a spacial amplitude light filter coated on a surface of the slab opposite to the surface carrying said pattern.
Claim 31
Dependent Claim
42 words
A grating means comprising a slab of silica glass having parallel corrugations on a surface thereof forming a surface relief pattern, in which the corrugation are filled with transparent material having an index of refraction different from that of the silica glass.
Claim 32
Dependent Claim
42 words
A grating means comprising a slab of silica glass having parallel corrugations on a surface thereof forming a surface relief pattern, in which the corrugation are filled with transparent material having an index of refraction different from that of the silica glass.
Claim 33
Dependent Claim
16 words
A grating as defined in claim 28 in which the transparent material is comprised of glass.
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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) | 1997-11-21 | 1998-05-23 | 1998-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-21 | 2002-05-23 | 2002-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-21 | 2006-05-23 | 2006-11-22 | $7700.00 | Window Closed / Lapsed |