METHODS AND SYSTEMS FOR DETECTING SMALL SPAN LOSS CHANGES IN FIBER OPTIC NETWORKS
First Claim
1. A method for detecting small span loss changes in a fiber optic span, comprising:
- sampling power measurements at a transmit point at a predetermined time;
sampling power measurements at a receive point at the predetermined time plus a time delay, wherein the transmit point and the receive point define endpoints of the fiber optic span;
calculating fiber span loss for the predetermined time responsive to the sampled power measurements at the transmit point and at the receive point;
repeating the sampling steps and the calculating step; and
integrating the calculated fiber span losses.
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Abstract
The present disclosure provides methods and systems for detecting small span loss changes in fiber optic networks. The present invention utilizes existing equipment without additional hardware to provide span loss measurements in a highly accurate manner. In an exemplary embodiment, the present invention utilizes power measurements associated with an optical supervisory channel (OSC) at both ends of a fiber span. These measurements are periodically sampled taking into account propagation delay along the fiber span. Further, these measurements are integrated or time-averaged to account for temporary fluctuations. The present invention can be utilized for intrusion detection (i.e., unwanted fiber taps), fiber degradation, and fiber aging performance. The present invention satisfies the criteria for a feasible (i.e., makes use of current architecture), cost-effective (i.e., does not require additional hardware), and highly accurate solution (i.e., capable of detecting span loss changes of 0.01 dB or 0.03%).
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Citations
20 Claims
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1. A method for detecting small span loss changes in a fiber optic span, comprising:
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sampling power measurements at a transmit point at a predetermined time; sampling power measurements at a receive point at the predetermined time plus a time delay, wherein the transmit point and the receive point define endpoints of the fiber optic span; calculating fiber span loss for the predetermined time responsive to the sampled power measurements at the transmit point and at the receive point; repeating the sampling steps and the calculating step; and integrating the calculated fiber span losses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for detecting small span loss changes in a fiber optic span, comprising:
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a processor communicatively coupled to memory and a network interface, wherein the processor is configured to; request a power measurement at a transmit point at a predetermined time; request a power measurement at a receive point at the predetermined time plus a time delay, wherein the transmit point and the receive point define endpoints of the fiber optic span; calculate fiber span loss of the fiber optic span responsive to the requested power measurements at the transmit point and at the receive point; store the calculated fiber span loss; and time average the calculated fiber span loss with one or more stored calculated fiber span losses. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. An optical network configured to detect small span loss changes in a fiber optic span, comprising:
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a first node comprising an add port for an optical supervisory channel and a first tap connected to the add port and a first photo-detector; a second node comprising a drop port for the optical supervisory channel and a second tap connected to the drop port and a second photo-detector, wherein the first node and the second node communicate the optical supervisory channel over the fiber optic span; and a computer communicatively coupled to the first photo-detector and the second photo-detector, wherein the computer is configured to; request a power measurement at the first photo-detector at a first predetermined time; request a power measurement at the second photo-detector at a second predetermined time, wherein the second predetermined time comprises the first predetermined time plus a time delay based on a length of the fiber optic span; calculate fiber span loss of the fiber optic span responsive to the requested power measurements; store the calculated fiber span loss; and time average the calculated fiber span loss with one or more stored calculated fiber span losses. - View Dependent Claims (20)
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Specification