Alarm system for an optical network

• US 9,954,609 B2
• Filed: 12/31/2013
• Issued: 04/24/2018
• Est. Priority Date: 12/31/2012
• Status: Active Grant

• Current Assignee: Network Integrity Systems, Inc.
• Original Assignee: Network Integrity Systems, Inc.
• Inventors: Murphy, Cary R., Goertzen, Daniel, Bridges, Mark K
• Primary Examiner(s): Sedighian, M. R.
• Assistant Examiner(s): Alagheband, Abbas H
• Application Number:
  US14/145,121
• Publication Number:
  US 20160218800A1
• Time in Patent Office: 1,575 Days
• Field of Search: 398 25, 398 72, 398 40, 398 28, 398 16, 398 13, 385 13, 385 12, 340566, 340541, 356 731
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: H04B 10/00 Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
• CPC Class Codes: H04B 10/071 using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
• CPC Class Codes: H04B 10/0793 Network aspects, e.g. central monitoring of transmission parameters
• CPC Class Codes: H04B 10/0795 Performance monitoring; Measurement of transmission parameters
• CPC Class Codes: H04B 10/27 Arrangements for networking
• CPC Class Codes: H04B 10/85 Protection from unauthorised access, e.g. eavesdrop protection
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0307 Multiplexers; Demultiplexers
• CPC Class Codes: H04L 41/06 Management of faults, events, alarms or notifications
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route

Abstract

A method is provided for detecting intrusion into optical fibers of a Passive Optical Network (PON) of the type which includes a multiplexing system at the head end for separating a data signal output at the head end to the plurality of fibers for supply to user end terminals and a data transmission system at each of the user end terminals for entering onto the fiber data as an optical signal. The method includes providing a monitor system having a transmitter at the head end and a monitor signal analysis system for analyzing changes in the optical monitor signal after transmission along the fiber for detecting an intrusion event. A monitor signal analysis system is provided at one or more user end terminals for detection and conversion of data from the analysis into a digital signal which is then transmitted from the user end terminals back to the head end using the data transmission system through the PON system or separately from the PON system.

Claims

1. A method for detecting intrusion into an optical network wherein the optical network comprises:

a plurality of fibers each having a first end at a head end of the network and a second user end;

the second user end of at least two of said plurality of fibers being connected to respective ones of a plurality of user end terminals;

a splitter/combiner system for separating a data signal output at said head end to said plurality of fibers for supply data signals to said plurality of user end terminals;

a data transmission system at each of said plurality of user end terminals for transmitting data as an optical signal along a respective one of said plurality of the fibers to said head end;

the method comprising;

transmitting a monitor signal from the head end on at least two of said plurality of fibers;

at said second user end of each respective fiber on which the monitoring signal is transmitted, detecting changes in the monitor signal after transmission along said respective one of said fibers, which changes are indicative of vibration, motion, or handling of said respective one of said fibers indicative of an attempt to intrude into said respective one of said fibers;

at said second user end of said respective one of said fibers, generating from said detected changes, change data signals containing data related to the changes;

encoding the change data signals to form encoded change data signals which are transmitted from said second user end of each respective one of said fibers back to the head end;

and at the head end, carrying out an analysis of the encoded change data signals from all of said respective fibers to detect said vibration, motion, or handling of each of said respective fibers indicative of an attempt to intrude into said respective fiber;

whereby said analysis can distinguish on which one of said fibers the changes indicative of an attempt to intrude have occurred.

2. The method according to claim 1 wherein the encoded change data signals are transmitted to the head end using the data transmission system.

3. The method according to claim 1 wherein the supply data signals and the monitor signals are time division split as TDM signals onto said fibers so that said TDM signals are received by a single photodetector/ADC at the second end of said fibers.

4. The method according to claim 3 wherein said TDM signals are combined at the second end of said fibers.

5. The method according to claim 3 wherein said TDM signals are combined at the head end.

6. The method according to claim 1 wherein the monitor signal is an out of band monitor wavelength of the supply data signals.

7. The method according to claim 1 wherein the monitor signal is a portion of the supply data signal.

8. The method according to claim 1 wherein the monitor signal is an unused wavelength of the supply data signals and is split with the supply data signals using WDM.

9. The method according to claim 1 wherein there is provided an insensitive lead-in fiber leading to the splitter/combiner system.

10. The method according to claim 1 wherein the fibers are located in an approved hardened conveyance so as to meet federal approval for alarmed carrier PDS.

11. The method according to claim 1 wherein connection between the head end and the user end terminals is provided solely by fiber.

12. The method according to claim 1 wherein connection between the head end and the user end terminals is provided by hybrid fiber/electrical.