Patent US4938561A successfully refreshed from Google Patents.
US4938561A
Expired / Lapsed
US
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Optical signal amplification with coupled fibers and optical pumping energy
Assignee: Prysmian Cables and Systems Ltd
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Filing: 1988-12-29
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Granted: 1990-07-03
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Expires: 2008-12-29
Abstract
Abstract An optical fibre structure usable in amplifying optical signals, comprising a length of optical fibre (1) which includes two uniformally spaced monomode optical cores (2,4) located within a common cladding (6) so as to provide two optical guidance paths, the optical characteristics of at least the cores being different such as to give the two guidance paths different propagation constants the values of which coincide for a predetermined coupling wavelength, one of the cores including a fluorescent material capable of producing stimulated emission. There is also disclosed a method of amplifying an optical signal using such an optical fibre structure, comprising arranging for the wavelength (λ s ) of the optical signal, the fluorescent wavelength of said material in said one core, and said predetermined coupling wavelength all to be substantially the same, launching optical pump energy having a different wavelength (λ p ) into said one core to pump the fluorescent material, launching the optical signal into the other core so that the optical signal transfers repeatedly between the two cores due to optical coupling and, when in said one core, gives rise to stimulated emission substantially at its own wavelength from the fluorescent material thereby becoming amplified, and extracting the amplified optical signal from the fibre structure when it is in said other core. A device (FIG. 4) using this method is also disclosed.
Inventors
- 👤 Giorgio Grasso
- 👤 Eleanor J. Tarbox
- 👤 Paul L. Scrivener
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:46
CPC Classifications
G; G02; G02F; G02F1/00; H; H01; H01S; H01S3/00; H01S3/09; H01S3/091; H01S3/094; H01S3/094003; G02F1/29; G02F1/31; G02F1/313; G02F1/3131; H01S3/05; H01S3/06; H01S3/063; H01S3/067; H01S3/06708; H01S3/06729; H01S3/06737; H01S3/094011
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
101 words
An optical fibre structure usable in amplifying optical signals, comprising a length of optical fibre (1) which includes two uniformally spaced monomode optical cores (2,4) located within a common cladding (6) so as to provide two optical guidance paths, the optical characteristics of at least the cores being different and providing the two guidance paths with different propagation constants, the values of such propagation constants being the same for a predetermined coupling wavelength, characterised in that one of the cores (4) includes a fluorescent material capable of producing stimulated emission at a wavelength substantially the same as said predetermined coupling wavelength.
Claim 2
Dependent Claim
101 words
An optical fibre structure usable in amplifying optical signals, comprising a length of optical fibre (1) which includes two uniformally spaced monomode optical cores (2,4) located within a common cladding (6) so as to provide two optical guidance paths, the optical characteristics of at least the cores being different and providing the two guidance paths with different propagation constants, the values of such propagation constants being the same for a predetermined coupling wavelength, characterised in that one of the cores (4) includes a fluorescent material capable of producing stimulated emission at a wavelength substantially the same as said predetermined coupling wavelength.
Claim 3
Dependent Claim
28 words
An optical fibre structure as claimed in claim 1, characterised in that the fluorescent material will produce stimulated emission substantially at a wavelength used in optical telecommunications transmissions.
Claim 4
Dependent Claim
48 words
An optical fibre structure as claimed in claim 1 or claim 2, characterised in that the length of optical fibre has a length equal to an integral number times the coupling beat length, between the two cores, of optical energy having a wavelength used in optical telecommunications transmission.
Claim 5
Dependent Claim
22 words
An optical fibre structure as claimed in any one of claims 1 or 2, characterised in that the fluorescent material is erbium.
Claim 6
Dependent Claim
20 words
An optical fibre structure as claimed in claim 1, characterised in that the fluorescent material is a rare earth dopant.
Claim 7
Dependent Claim
18 words
An optical fibre structure as claimed in claim 5, characterised in that the rare earth dopant is neodymium.
Claim 8
Dependent Claim
160 words
A method of amplifying an optical signal using an optical fibre structure as claimed in claim 1, comprising arranging for the wavelength (λ s ) of the optical signal, the fluorescent wavelength of said material in said one core, and said predetermined coupling wavelength all to be substantially the same, applying an electrical field to at least one of the cores whereby to alter its propagation constant by the electrooptic effect and hence alter said coupling wavelength, launching optical pump energy having a different wavelength (λ p ) into said one core to pump the fluorescent material, launching the optical signal into the other core so that the optical signal transfers repeatedly between the two cores due to optical coupling and, when in said one core gives rise to stimulated emission substantially at its own wavelength from the fluorescent material thereby becoming amplified, and extracting the amplified optical signal from the fibre structure when it is in said other core.
Claim 9
Dependent Claim
28 words
A method of amplifying an optical signal as claimed in claim 7 characterised in that the optical pump energy is launched into both ends of said one core.
Claim 10
Dependent Claim
133 words
A method of amplifying an optical signal using an optical fibre structure as claimed in claim 1, comprising arranging for the wavelength (λ s ) of the optical signal, the fluorescent wavelength of said material in said one core, and said predetermined coupling wavelength all to be substantially the same, launching optical pump energy having a different wavelength (λ p ) into said one core to pump the fluorescent material, launching the optical signal into the other core so that the optical signal transfers repeatedly between the two cores due to optical coupling and, when in said one core gives rise to stimulated emission substantially at its own wavelength from the fluorescent material thereby becoming amplified, and extracting the amplified optical signal from the fibre structure when it is in said other core.
Claim 11
Dependent Claim
91 words
A device for amplifying an optical signal, comprising an optical fibre structure as claimed in claim 1 having, at at least one end a planar optic element (18,20) which includes two optical paths (18a, 18b) which are optically matched with, and are at one end positioned in register with, respective ones (4,2) of the fibre cores, the two optical paths of the planar element diverging in a direction away from the fibre, whereby to provide relatively widely spaced apart optical input or output means leading to or from the fibre cores.
Claim 12
Dependent Claim
23 words
A device as claimed in claim 10 characterised in that the optical fibre structure has such a planar optic element at each end.
Claim 13
Dependent Claim
62 words
A device as claimed in claim 10 or 11 wherein, in the fibre, two electrodes (30,32;44) are provided within the cladding and are located with at least one core (4) between them for applying an electrical field to that core whereby to alter its propagation constant by the electro-optic effect and hence to alter said coupling wavelength, the device thereby being tunable.
Claim 14
Dependent Claim
134 words
An optical fibre structure usable in amplifying optical signals, comprising a length of optical fibre (1) which includes two uniformally spaced monomode optical cores (2,4) located within a common cladding (6) so as to provide two optical guidance paths, the optical characteristics of at least the cores being different and providing the two guidance paths with different propagation constants, the values of such propagation constants being the same for a predetermined coupling wavelength and one of the cores (4) including a fluorescent material capable of producing stimulated emission, two electrodes (30,32;44) within the cladding and disposed with at least one core (4) between them for applying an electrical field to that core whereby to alter its propagation constant by the electrooptical effect and hence to alter said coupling wavelength, the structure thereby being tunable.
Claim 15
Dependent Claim
134 words
An optical fibre structure usable in amplifying optical signals, comprising a length of optical fibre (1) which includes two uniformally spaced monomode optical cores (2,4) located within a common cladding (6) so as to provide two optical guidance paths, the optical characteristics of at least the cores being different and providing the two guidance paths with different propagation constants, the values of such propagation constants being the same for a predetermined coupling wavelength and one of the cores (4) including a fluorescent material capable of producing stimulated emission, two electrodes (30,32;44) within the cladding and disposed with at least one core (4) between them for applying an electrical field to that core whereby to alter its propagation constant by the electrooptical effect and hence to alter said coupling wavelength, the structure thereby being tunable.
Claim 16
Dependent Claim
24 words
An optical fibre structure as claimed in claim 13 characterised in that the two electrodes (30,32) are located with both cores (2,4) between them.
Claim 17
Dependent Claim
27 words
An optical fibre structure as claimed in claim 13, characterised in that the two electrodes (44) are located with only one (4) of the cores between them.
Claim 18
Dependent Claim
22 words
An optical fibre structure as claimed in claim 15, comprising two further electrodes (48) located with the other core (2) between them.
Claim 19
Dependent Claim
33 words
An optical fibre structure as claimed in any one of claims 14 to 16 or 13 wherein at least said one core is of a soft glass exhibiting a relatively large electro-optic effect.
Claim 20
Dependent Claim
24 words
An optical fibre structure as claimed in claim 17 wherein the common cladding is of a soft glass exhibiting a relatively large electro-optic effect.
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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) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |