US5187362A
Expired / Lapsed
US
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Loss detection in a branched optical fiber
Assignee: British Telecommunications PLC
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Filing: 1989-12-05
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Granted: 1993-02-16
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Expires: 2009-12-05
Abstract
Abstract A method is described of detecting loss in a branched optical fibre network comprising a first optical fibre (1) and a plurality of second optical fibres (3) each of which is coupled to the first optical fibre. The first optical fibre (1) constitutes a main line. The method comprises the steps of launching a pulse into the main line (1) and monitoring the main line for changes in attenuation of reflected signals returning from the reflectors (5).
Inventors
- 👤 Peter J. Keeble
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:28
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/30; G01M11/31; G01M11/3109; G01M11/3136; H; H04; H04B; H04B10/00; H04B10/07; H04B10/071
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
113 words
A method of detecting loss in a branched optical fibre network comprising a first optical fibre and a plurality of second optical fibres each of which is coupled to the first optical fibre, the first optical fibre constituting a main line and the second optical fibres constituting branch lines, a respective reflector being associated with each of the branch lines, the method comprising the steps of launching a pulse into the main line and monitoring the main line for attenuation of reflected signals returning from the reflectors, a monitored attenuation of a given reflected signal being indicative of loss in the branch line associated with the reflector giving rise to that reflected signal.
Claim 2
Independent Claim
113 words
A method of detecting loss in a branched optical fibre network comprising a first optical fibre and a plurality of second optical fibres each of which is coupled to the first optical fibre, the first optical fibre constituting a main line and the second optical fibres constituting branch lines, a respective reflector being associated with each of the branch lines, the method comprising the steps of launching a pulse into the main line and monitoring the main line for attenuation of reflected signals returning from the reflectors, a monitored attenuation of a given reflected signal being indicative of loss in the branch line associated with the reflector giving rise to that reflected signal.
Claim 3
Dependent Claim
19 words
A method as claimed in claim 1, wherein the reflected signals are monitored with respect to a reference signal.
Claim 4
Dependent Claim
28 words
A method as claimed in claim 2, wherein the reflected signals are monitored with respect to a reference reflection signal from a location positioned in the main line.
Claim 5
Dependent Claim
28 words
A method as claimed in claim 1, wherein pulses of different frequency are launched into the main line, and reflection from reflectors having different wavelength responses is monitored.
Claim 6
Dependent Claim
118 words
Apparatus for detecting losses in a branched optical fibre network comprising a first optical fibre and a plurality of second optical fibres each of which is coupled to the first optical fibre, the first optical fibre constituting a main line and the second optical fibres constituting branch lines, the apparatus comprising means for launching a pulse into the main line, a respective reflector located in the path of the pulse in each of the branch lines, and means for monitoring the main line for attenuation of reflected signals returning from the reflectors, a monitored attenuation of a given reflected signal being indicative of loss in the branch line associated with the reflector giving rise to that reflected signal.
Claim 7
Dependent Claim
118 words
Apparatus for detecting losses in a branched optical fibre network comprising a first optical fibre and a plurality of second optical fibres each of which is coupled to the first optical fibre, the first optical fibre constituting a main line and the second optical fibres constituting branch lines, the apparatus comprising means for launching a pulse into the main line, a respective reflector located in the path of the pulse in each of the branch lines, and means for monitoring the main line for attenuation of reflected signals returning from the reflectors, a monitored attenuation of a given reflected signal being indicative of loss in the branch line associated with the reflector giving rise to that reflected signal.
Claim 8
Dependent Claim
21 words
Apparatus as claimed in claim 5, wherein at least one of the branch lines is provided with a plurality of reflectors.
Claim 9
Dependent Claim
24 words
Apparatus as claimed in claim 5, further comprising means for generating a reference signal, said means being located in the path of the pulse.
Claim 10
Dependent Claim
21 words
Apparatus as claimed in claim 7, wherein a reference reflector located in the main line constitutes the reference signal generating means.
Claim 11
Dependent Claim
16 words
Apparatus as claimed in claim 5, wherein each reflector is located within the associated branch line.
Claim 12
Dependent Claim
17 words
Apparatus as claimed in claim 5, wherein each reflector is located externally of the associated branch line.
Claim 13
Dependent Claim
19 words
Apparatus as claimed in claim 10, wherein each reflector is located at a termination of the associated branch line.
Claim 14
Dependent Claim
14 words
Apparatus as claimed in claim 5, wherein each reflector is a passive optical reflector.
Claim 15
Dependent Claim
19 words
Apparatus as claimed in claim 5, wherein each reflector comprises means for reflecting a distinguishable portion of the pulse.
Claim 16
Dependent Claim
18 words
Apparatus as claimed in claim 13, wherein the distinguishable portion is a particular wavelength or range of wavelengths.
Claim 17
Dependent Claim
20 words
Apparatus as claimed in claim 5, wherein each reflector is provided with means for imposing a modulation on the pulse.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-02-16 | 1996-08-17 | 1997-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-16 | 2000-08-17 | 2001-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-16 | 2004-08-17 | 2005-02-16 | $7700.00 | Window Closed / Lapsed |