US6289699B1
Expired / Lapsed
US
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Wavelength selective optical couplers
Assignee: Mellanox Technologies Silicon Photonics Inc
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Filing: 1998-03-06
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Granted: 2001-09-18
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Expires: 2018-03-06
Abstract
Abstract A wavelength selective optical fiber coupler having various applications in the field of optical communications is disclosed. The coupler is composed of dissimilar waveguides in close proximity. A light induced, permanent index of refraction grating is recorded in the coupler waist The grating filters and transfers energy within a particular range of wavelengths from a first waveguide to a second waveguide. Transversely asymmetric gratings provide an efficient means of energy transfer. The coupler can be used to combine or multiplex a plurality of lasers operating at slightly different wavelengths into a single fiber. Other embodiments such as a dispersion compensator and gain flattening filter are disclosed.
Inventors
- 👤 Anthony S. Kewitsch
- 👤 George A. Rakuljic
- 👤 Amnon Yariv
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:50
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29331; G02B6/29332; G02B6/29334; G02B6/02; G02B6/02057; G02B6/02076; G02B6/02114; G02B6/02123; G02B6/02133; G02B6/02138; G02B6/02195; G02B6/022; G02B6/02204; G02B6/10; G02B6/12; G02B6/12007; G02B6/29379; G02B6/2938; G02B6/29382; G02B6/29383; G02B6/0208; G02B6/02085; G02B6/021; G02B6/02109; G02B6/02152; G02B6/2804; G02B6/2821; G02B6/2835; H; H04; H04J; H04J14/00; H04J14/02; H04J14/0201; H04J14/0202; H04J14/0206; H04J14/0209; H04J14/0213; H04J14/0215; H04J14/0219
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
116 words
A method of enhancing the performance of a fused, grating assisted mode coupler having a coupling region comprising the steps of: forming a coupler having a coupling region with a cross-sectional dimension of 20 microns or less, the coupler having substantial photosensitivity enhancing dopant throughout the cross-sectional area in the coupling region; enhancing the photosensitivity of the coupler at least in the coupling region by indiffusion of a gas into the cross-sectional area of the coupler to a level such that an actinic illumination exposure to <1kJ/cm 2 impresses an index of refraction change >10 −5 within the coupling region; and writing the grating in the photosensitivity enhanced coupling region of the coupler with actinic illumination.
Claim 2
Independent Claim
116 words
A method of enhancing the performance of a fused, grating assisted mode coupler having a coupling region comprising the steps of: forming a coupler having a coupling region with a cross-sectional dimension of 20 microns or less, the coupler having substantial photosensitivity enhancing dopant throughout the cross-sectional area in the coupling region; enhancing the photosensitivity of the coupler at least in the coupling region by indiffusion of a gas into the cross-sectional area of the coupler to a level such that an actinic illumination exposure to <1kJ/cm 2 impresses an index of refraction change >10 −5 within the coupling region; and writing the grating in the photosensitivity enhanced coupling region of the coupler with actinic illumination.
Claim 3
Dependent Claim
27 words
The method set forth in claim 1 above wherein the step of enhancing the photosensitivity comprises fusing the coupler at least in part with a hydrogen flame.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the step of enhancing the photosensitivity comprises subjecting the coupler waist region to chemical indiffusion.
Claim 5
Dependent Claim
20 words
The method of claim 3 above wherein the chemical indiffusion includes the use of H 2 or D 2 gas.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the step of enhancing the photosensitivity includes chemical outdiffusion.
Claim 7
Independent Claim
142 words
A method of fabricating a fused, grating assisted mode coupler from at least two optical fibers comprising the steps of: providing at least two optical fibers at least one of which has a photosensitive dopant distributed throughout the cladding thereof; forming a coupler by longitudinally merging the at least two fibers by elongating and fusing the fibers to form a coupling region in which the cross-sectional dimension is sufficiently small that the doped cladding alone supports optical wave propagation in the at least one photsensitized fiber; further enhancing the photosensitivity of the coupler in the distributed dopant region by gas indiffusion to a level such that an actinic illumination exposure to <1kJ/cm 2 impresses an index of refraction change >10 −5 the photosensitive region; and writing the grating in the coupler in the photosensitivity enhanced region of the coupler with actinic illumination.
Claim 8
Independent Claim
142 words
A method of fabricating a fused, grating assisted mode coupler from at least two optical fibers comprising the steps of: providing at least two optical fibers at least one of which has a photosensitive dopant distributed throughout the cladding thereof; forming a coupler by longitudinally merging the at least two fibers by elongating and fusing the fibers to form a coupling region in which the cross-sectional dimension is sufficiently small that the doped cladding alone supports optical wave propagation in the at least one photsensitized fiber; further enhancing the photosensitivity of the coupler in the distributed dopant region by gas indiffusion to a level such that an actinic illumination exposure to <1kJ/cm 2 impresses an index of refraction change >10 −5 the photosensitive region; and writing the grating in the coupler in the photosensitivity enhanced region of the coupler with actinic illumination.
Claim 9
Independent Claim
117 words
A method for photosensitizing an optical fiber having a core and cladding by (a) drawing down an optical fiber with photosensitive cladding to a narrow waist in which the core is vestigial and the cladding alone confines optical energy, (b) exposing said narrow waist to a photosensitizing gas selected from the group consisting of H 2 and D 2 , (c) maintaining the exposure for a time sufficient for said photosensitizing gas to permeate the said photosensitive cladding at the location of the said narrow waist, such that actinic illumination exposure of<1kJ/cm 2 impresses an index of refraction change >10 −5 and (d) impressing an index of refraction grating in said narrow waist by said actinic illumination.
Claim 10
Independent Claim
117 words
A method for photosensitizing an optical fiber having a core and cladding by (a) drawing down an optical fiber with photosensitive cladding to a narrow waist in which the core is vestigial and the cladding alone confines optical energy, (b) exposing said narrow waist to a photosensitizing gas selected from the group consisting of H 2 and D 2 , (c) maintaining the exposure for a time sufficient for said photosensitizing gas to permeate the said photosensitive cladding at the location of the said narrow waist, such that actinic illumination exposure of<1kJ/cm 2 impresses an index of refraction change >10 −5 and (d) impressing an index of refraction grating in said narrow waist by said actinic illumination.
Claim 11
Independent Claim
115 words
A method for photosensitizing a fused optical fiber coupler by (a) drawing down a multitude of optical fibers, at least one of which possesses photosensitizable cladding to a narrow coupler waist in which the fibers are fused along a length; (b) exposing the material originally comprising said photosensitizable claddings within said narrow coupler waist to a photosensitizing gas selected from the group consisting of H 2 and D 2 , and (c) maintaining the exposure to the gas for a time sufficient for said photosensitizing gas to permeate said narrow coupler waist, such that actinic illumination exposure of <1kJ/cm 2 impresses an index of refraction change >10 −5 in the photosensitive portion of the waist.
Claim 12
Independent Claim
115 words
A method for photosensitizing a fused optical fiber coupler by (a) drawing down a multitude of optical fibers, at least one of which possesses photosensitizable cladding to a narrow coupler waist in which the fibers are fused along a length; (b) exposing the material originally comprising said photosensitizable claddings within said narrow coupler waist to a photosensitizing gas selected from the group consisting of H 2 and D 2 , and (c) maintaining the exposure to the gas for a time sufficient for said photosensitizing gas to permeate said narrow coupler waist, such that actinic illumination exposure of <1kJ/cm 2 impresses an index of refraction change >10 −5 in the photosensitive portion of the waist.
Claim 13
Independent Claim
127 words
A method for writing a strong grating in a fused, grating assisted mode coupler for optical waves, the mode coupler having a coupling region comprising two fused fibers, and the method comprising the steps of: forming two optical fibers having photosensitivity enhancing dopant extending substantially throughout the cladding in at least a coupling region; concurrently elongating and fusing the fibers to form a fused coupling region; continuing drawing the fused fibers down to a cross-sectional dimension of less than 20 microns to establish a coupling region of essentially doped cladding with only a vestigial core, for receiving an index of refraction grating in the cladding, and exposing the coupling region to actinic illumination in a periodic pattern to write an index of refraction grating in the cladding.
Claim 14
Independent Claim
127 words
A method for writing a strong grating in a fused, grating assisted mode coupler for optical waves, the mode coupler having a coupling region comprising two fused fibers, and the method comprising the steps of: forming two optical fibers having photosensitivity enhancing dopant extending substantially throughout the cladding in at least a coupling region; concurrently elongating and fusing the fibers to form a fused coupling region; continuing drawing the fused fibers down to a cross-sectional dimension of less than 20 microns to establish a coupling region of essentially doped cladding with only a vestigial core, for receiving an index of refraction grating in the cladding, and exposing the coupling region to actinic illumination in a periodic pattern to write an index of refraction grating in the cladding.
Claim 15
Dependent Claim
58 words
The method as set forth in claim 9 above, wherein the dopant includes germanium, and finer including the steps of exposing the coupling region of both the fibers to a laser beam from a laser of about 100 mJ or more power for about 10 minutes, to write the periodic pattern in the cladding of both the fibers.
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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) | 2004-09-17 | 2005-03-19 | 2005-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-09-17 | 2009-03-19 | 2009-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-09-17 | 2013-03-19 | 2013-09-18 | $7700.00 | Window Closed / Lapsed |