Drop discriminating network alarm system utilizing a single sensing fiber
US9374157B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 2014 |
| Grant date | Jun 21, 2016 |
| Priority date | — |
| Expiry date | Aug 12, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/85
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method is provided for detecting movement indicative of intrusion events on optical drop fibers of a network where the individual drop fiber can be identified to locate the event. The method uses a monitor system at the network end and multiplexing the monitor signal along the individual fibers to the respective terminals. At each of the terminals, the monitor signal is returned unchanged or in modified form along the same or different fibers to the network end. At the network end the received monitor signals is analyzed for changes in said monitor signals indicative of movement. Which one or more of the drop fibers has triggered the alarm is determined by modifying the monitor signal in wavelength or polarization, or by applying a modulation at the source and/or at multiplexing and/or at returning so that the monitor signal of one drop fiber has a difference from the monitor signal of another drop fiber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.