EP0324541A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Amplifying optical signals
Assignee: Prysmian Cables and Systems Ltd
•
Filing: 1989-01-05
•
Granted: —
•
Expires: 2009-01-05
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 (Figure 4) using this method is also disclosed.
Inventors
- 👤 Eleanor Joan Tarbox
- 👤 Paul Laurance Scrivener
- 👤 Giorgio Grasso
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:15
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: 19
Claim 1
Independent Claim
87 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 such as to give the two guidance paths different propagation constants the values of which coincide for a predetermined coupling wavelength, characterised in that one of the cores (4) includes a fluorescent material capable of producing stimulated emission.
Claim 2
Dependent Claim
87 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 such as to give the two guidance paths different propagation constants the values of which coincide for a predetermined coupling wavelength, characterised in that one of the cores (4) includes a fluorescent material capable of producing stimulated emission.
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 to 3, 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
65 words
An optical fibre structure as claimed in any one of the preceding claims characterised in that 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 structure thereby being tunable.
Claim 9
Dependent Claim
24 words
An optical fibre structure as claimed in Claim 7 characterised in that the two electrodes (30,32) are located with both cores (2,4) between them.
Claim 10
Dependent Claim
27 words
An optical fibre structure as claimed in Claim 7, characterised in that the two electrodes (44) are located with only one (4) of the cores between them.
Claim 11
Dependent Claim
22 words
An optical fibre structure as claimed in Claim 9, comprising two further electrodes (48) located with the other core (2) between them.
Claim 12
Dependent Claim
31 words
An optical fibre structure as claimed in any one of claims 7 to 10 wherein at least said one core is of a soft glass exhibiting a relatively large electro-optic effect.
Claim 13
Dependent Claim
24 words
An optical fibre structure as claimed in Claim 11 wherein the common cladding is of a soft glass exhibiting a relatively large electro-optic effect.
Claim 14
Independent Claim
134 words
A method of amplifying an optical signal using an optical fibre structure as claimed in any preceding claim, 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 15
Dependent Claim
28 words
A method of amplifying an optical signal as claimed in claim 13 characterised in that the optical pump energy is launched into both ends of said one core.
Claim 16
Dependent Claim
43 words
A method of amplifying an optical signal as claimed in claim 13 or claim 14, comprising applying an electrical field to at least one of the cores whereby to alter its propagation constant by the electro-optic effect and hence alter said coupling wavelength.
Claim 17
Independent Claim
88 words
A device for amplifying an optical signal, comprising an optical fibre structure as claimed in a planar optic element (18,20) which includes two optical paths (18 a , 18 b ) 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 18
Dependent Claim
23 words
A device as claimed in claim 16 characterised in that the optical fibre structure has such a planar optic element at each end.
Claim 19
Dependent Claim
63 words
A device as claimed in claim 16 or claim 17 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.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.