US4911515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical fiber communications system with optical fiber monitoring
Assignee: Nortel Networks Ltd
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Filing: 1988-12-22
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Granted: 1990-03-27
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Expires: 2008-12-22
Abstract
Abstract Optical communications fibers extend from a central office to subscribers' premises for carrying signals in both directions between optical transmitters and receivers. Each subscriber's optical receiver continuously reflects back to its fiber, and then to the central office, about 20 percent of the light which it receives. At the central office the reflected light is monitored in turn for each subscriber, and is correlated with the signal transmitted to that subscriber to provide a signal for optical time domain reflectometry of the respective subscriber's fiber connection.
Inventors
- 👤 Vincent C. So
- 👤 Paul J. Vella
- 👤 Fred A. Huszarik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:49
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4204; G01; G01M; G01M11/00; G01M11/30; G01M11/31; G01M11/3109; G01M11/3154; H; H04; H04B; H04B10/00; H04B10/07; H04B10/071
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
126 words
An optical fiber communications system comprising: a plurality of optical fibers each extending from a central location to a respective remote location, each optical fiber being coupled to an optical signal receiver at the respective remote location and being coupled to a respective optical signal transmitter and a respective optical receiver at the central location; means at the optical receiver at each remote location for continuously reflecting back to the respective optical fiber a minor part of light received via the fiber from the respective transmitter at the central location; monitoring means at the central location; and switching means at the central location for selectively connecting the monitoring means to an optical receiver at the central location for monitoring light received thereby via the respective fiber.
Claim 2
Dependent Claim
126 words
An optical fiber communications system comprising: a plurality of optical fibers each extending from a central location to a respective remote location, each optical fiber being coupled to an optical signal receiver at the respective remote location and being coupled to a respective optical signal transmitter and a respective optical receiver at the central location; means at the optical receiver at each remote location for continuously reflecting back to the respective optical fiber a minor part of light received via the fiber from the respective transmitter at the central location; monitoring means at the central location; and switching means at the central location for selectively connecting the monitoring means to an optical receiver at the central location for monitoring light received thereby via the respective fiber.
Claim 3
Dependent Claim
17 words
A system as claimed in claim 1 wherein the monitoring means comprises optical time domain reflectometry means.
Claim 4
Dependent Claim
46 words
A system as claimed in claim 1 wherein said means at the optical receiver at each remote location for reflecting a minor part of light comprises means for reflecting back to the respective optical fiber 1 to 30 percent of the light received via the fiber.
Claim 5
Dependent Claim
45 words
A system as claimed in claim 1 wherein said means at the optical receiver at each remote location for reflecting a minor part of light comprises means for reflecting back to the respective optical fiber about 15 percent of the light received via the fiber.
Claim 6
Dependent Claim
184 words
An optical fiber communications system comprising: a plurality of optical fibers each extending from a central location to a respective remote location, each optical fiber being coupled to an optical receiver at the respective remote location and being coupled to a respective optical transmitter and a respective optical receiver at the central location; means at the optical receiver at each remote location for continuously reflecting back to the respective optical fiber a minor part of light received via the fiber from the respective transmitter at the central location; monitoring means at the central location; and switching means at the central location for selectively connecting the monitoring means to an optical receiver at the central location for monitoring light received thereby via the respective fiber; wherein the monitoring means comprises optical time domain reflectometry means comprising means for variably delaying a signal supplied to an optical transmitter at the central location, and a correlator means for correlating the delayed signal with a signal received by an optical receiver at the central location, the optical transmitter and optical receiver being coupled to the same optical fiber.
Claim 7
Dependent Claim
184 words
An optical fiber communications system comprising: a plurality of optical fibers each extending from a central location to a respective remote location, each optical fiber being coupled to an optical receiver at the respective remote location and being coupled to a respective optical transmitter and a respective optical receiver at the central location; means at the optical receiver at each remote location for continuously reflecting back to the respective optical fiber a minor part of light received via the fiber from the respective transmitter at the central location; monitoring means at the central location; and switching means at the central location for selectively connecting the monitoring means to an optical receiver at the central location for monitoring light received thereby via the respective fiber; wherein the monitoring means comprises optical time domain reflectometry means comprising means for variably delaying a signal supplied to an optical transmitter at the central location, and a correlator means for correlating the delayed signal with a signal received by an optical receiver at the central location, the optical transmitter and optical receiver being coupled to the same optical fiber.
Claim 8
Dependent Claim
46 words
A system as claimed in claim 5 wherein said means at the optical receiver at each remote location for reflecting a minor part of light comprises means for reflecting back to the respective optical fiber 1 to 30 percent of the light received via the fiber.
Claim 9
Dependent Claim
45 words
A system as claimed in claim 5 wherein said means at the optical receiver at each remote location for reflecting a minor part of light comprises means for reflecting back to the respective optical fiber about 15 percent of the light received via the fiber.
Claim 10
Dependent Claim
125 words
A bidirectional optical fiber communications system comprising: a plurality of optical fibers each extending from a central location to a respective remote location, each optical fiber being coupled to an optical transmitter and an optical receiver at the respective remote location and being coupled to a respective optical transmitter and a respective optical receiver at the central location; means at each remote location for continuously reflecting back to the respective optical fiber a minor part of light received via the fiber from the respective transmitter at the central location; monitoring means at the central location; and switching means at the central location for selectively connecting the monitoring means to an optical receiver at the central location for monitoring light received thereby via the respective fiber.
Claim 11
Dependent Claim
125 words
A bidirectional optical fiber communications system comprising: a plurality of optical fibers each extending from a central location to a respective remote location, each optical fiber being coupled to an optical transmitter and an optical receiver at the respective remote location and being coupled to a respective optical transmitter and a respective optical receiver at the central location; means at each remote location for continuously reflecting back to the respective optical fiber a minor part of light received via the fiber from the respective transmitter at the central location; monitoring means at the central location; and switching means at the central location for selectively connecting the monitoring means to an optical receiver at the central location for monitoring light received thereby via the respective fiber.
Claim 12
Dependent Claim
17 words
A system as claimed in claim 8 wherein the monitoring means comprises optical time domain reflectometry means.
Claim 13
Dependent Claim
46 words
A system as claimed in claim 8 wherein said means at the optical receiver at each remote location for reflecting a minor part of light comprises means for reflecting back to the respective optical fiber 1 to 30 percent of the light received via the fiber.
Claim 14
Dependent Claim
45 words
A system as claimed in claim 8 wherein said means at the optical receiver at each remote location for reflecting a minor part of light comprises means for reflecting back to the respective optical fiber about 15 percent of the light received via the fiber.
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) | 1993-03-26 | 1993-09-25 | 1994-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-26 | 1997-09-25 | 1998-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-26 | 2001-09-25 | 2002-03-27 | $7700.00 | Window Closed / Lapsed |