High-Sensitivity Forward-Transmission Vibration Sensing for Real-World Urban Fiber Infrastructure
AssigneeNEC Laboratories America, Inc.
InventorsJian Fang, Ming-Fang Huang, Ting Wang
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Abstract
A high-sensitivity forward-transmission vibration sensing system and method for urban fiber infrastructure. The system utilizes adaptive time-frequency (T-F) masking to identify weak vibration events by suppressing common laser phase noise in the time-frequency domain. Accurate localization is achieved through in-band laser phase noise suppression using a detuning matrix to balance correlation terms. The invention enables detection and localization of real-world events, such as footsteps and construction activity, in noisy metropolitan environments where conventional filtering fails.
Claims4
A system for high-sensitivity forward-transmission vibration sensing, comprising:
- a laser source configured to generate an optical signal;
- a transmitter configured to launch counter-propagating probe signals through at least two fibers in a common cable;
- a receiver comprising at least one coherent receiver configured to detect the probe signals;
- and
- a processor configured to:
- transform detected phase signals into a time-frequency domain;
- apply an adaptive time-frequency mask to identify a vibration event by suppressing common phase noise;
- and
- localize the vibration event using in-band laser phase noise suppression via a detuning matrix.
Dependencies are inferred from the claim text.