UNIDIRECTIONAL ABSOLUTE OPTICAL ATTENUATION MEASUREMENT WITH OTDR
First Claim
1. Monitoring device for monitoring absolute loss between two points in an optical network, said network comprising an optical transmission path having a head end and at least one remote end, an optical signal returning device at a first location in the network and a reference optical signal returning device at a second location in the network,wherein the monitoring device comprises:
- equipment for communicating with the head end for sending a test signal and for receiving a first returning signal from the optical signal returning device and a second returning reference signal from the reference optical signal returning device, both the first returning signal and the second returning reference signal being derived from the test signal, the equipment having means for comparing the first returning signal and the second returning reference signal and for deriving therefrom a value related to the absolute loss between the first and second locations in the network, wherein at least one of the optical signal returning device and the reference optical signal returning device is a wavelength selective device.
2 Assignments
0 Petitions
Accused Products
Abstract
Devices and methods for optical measurements in point-to-point and point-to-multipoint networks, e.g. like PON networks with splitters are described in which reflected power from some known reflections at the end of the lines is used to determine the attenuation and stability of the attenuation of each line. Also a reference reflection is used at the beginning of the network so that an absolute loss measurement between the points of reflection and the reference reflection can be made. In a further aspect wavelength selective stable reflections and reflectors are used, to provide reflections in a wavelength range that does not interfere with normal operation.
55 Citations
14 Claims
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1. Monitoring device for monitoring absolute loss between two points in an optical network, said network comprising an optical transmission path having a head end and at least one remote end, an optical signal returning device at a first location in the network and a reference optical signal returning device at a second location in the network,
wherein the monitoring device comprises: equipment for communicating with the head end for sending a test signal and for receiving a first returning signal from the optical signal returning device and a second returning reference signal from the reference optical signal returning device, both the first returning signal and the second returning reference signal being derived from the test signal, the equipment having means for comparing the first returning signal and the second returning reference signal and for deriving therefrom a value related to the absolute loss between the first and second locations in the network, wherein at least one of the optical signal returning device and the reference optical signal returning device is a wavelength selective device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Unidirectional method of monitoring absolute loss between two points in an optical network, said network comprising an optical transmission path having a head end and at least one remote end, an optical signal returning device at a first location in the network and a reference optical signal returning device at a second location in the network,
wherein the method comprises: -
sending a test signal from the head end, receiving a first returning signal from the optical signal returning device and a second returning reference signal from the reference optical signal returning device, both the first returning signal and the second returning reference signal being derived from the test signal, comparing the first returning signal and the second returning reference signal and deriving therefrom a value related to the absolute loss between the first and second locations in the network, wherein at least one of the first returning signal and the second reference returning signal is a first wavelength selective signal. - View Dependent Claims (10, 11)
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12. An optical device comprising:
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a first port for connection to a first optical fiber, a second port for connection to a second optical fiber, a third port connected to an optical signal returning device, wherein when an optical signal is fed to the first port, the optical device returns a signal back through the first port that is wavelength selective.
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13. A computer program product that when executed on a processing engine, can provide a method of monitoring absolute loss between two points in an optical network, wherein the network comprises an optical transmission path having a head end and at least one remote end, an optical signal returning device at a first location in the network and a reference optical signal returning device at a second location in the network, the computer program product providing for:
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sending a test signal from the head end, receiving a first returning signal from the optical signal returning device and a second returning reference signal from the reference optical signal returning device, both the first returning signal and the second returning reference signal being derived from the test signal, comparing the first returning signal and the second returning reference signal and deriving therefrom a value related to the absolute loss between the first and second locations in the network, wherein at least one of the first returning signal and the second reference returning signal is a first wavelength selective signal. - View Dependent Claims (14)
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Specification