System and method for monitoring optical fiber integrity between the telecommunications provider and a customer's premises

• US 6,583,867 B1
• Filed: 08/13/1999
• Issued: 06/24/2003
• Est. Priority Date: 08/13/1999
• Status: Expired due to Fees

• Current Assignee: Fitel USA Corporation
• Original Assignee: Fitel USA Corporation
• Inventors: Jennings, Mark Richard, Leone, Frank Salvatore, Pimpinella, Richard Joseph
• Primary Examiner(s): Nguyen, Tu T.
• Application Number:
  US09/374,169
• Time in Patent Office: 1,411 Days
• Field of Search: 356/73.1, 385/24, 385/39, 385/134-139, 385/48, 385/15-16, 385/100, 385/31-32, 359/109-127, 359/166, 359/168
• US Class Current: 356/73.1
• CPC Class Codes: H04B 10/071 using a reflected signal, e.g. using optical time domain reflectometers [OTDR]

Abstract

A system and method of monitoring and testing the integrity of a dedicated pair of optical fibers extending between a telecommunications provider to a customer facility through the optical fiber network, of the telecommunications provider. The system contains an optical transmission module, a monitoring module, and a first wavelength division multiplexing module which are located at the telecommunication provider'"'"'s facility. A second wavelength division multiplexer module is located at or just prior to the customer'"'"'s facility. The optical transmission module introduces test signals into the first dedicated optical fiber and which travels to the customer facility through the optical fiber network. At the customer facility, the test signal is looped into the second dedicated optical fiber. The test signal then returns to the telecommunications provider'"'"'s facility, wherein the test signal is received and processed.

Claims

1. In a telecommunications system where two dedicated optical fibers extend from the central office of a telecommunications provider to provide signals at a first primary transmission frequency to a customer facility through an optical fiber network, a method of remotely testing the two optical fibers, comprising the steps of:

introducing an optical test signal at a second frequency above or below the primary transmission frequency into a first of the two dedicated optical fibers at the central office of the telecommunications provider;

providing a wavelength division multiplexer at or just prior to the customer facility that is coupled to both of the two dedicated optical fibers wherein said wavelength division multiplexer removes said optical test signal from the first of the two dedicated optical fibers;

looping said optical test signal removed from the first of the two dedicated optical fibers by the wavelength division multiplexer to the second of the two dedicated optical fibers to return the test signal at the second frequency to the central office of the telecommunications provider;

monitoring said optical test signal in the second of the two dedicated optical fibers at the central office; and

comparing the optical test signal introduced into the first of the two dedicated optical fibers to the optical test signal received from the second of the two dedicated optical fibers at said central office, thereby determining losses in the two dedicated optical fibers.

2. The method according to claim 1, wherein said step of introducing an optical test signal into a first of two dedicated optical fibers, includes the substeps of:

coupling a first wavelength division multiplexer to the first of the two dedicated optical fibers;

providing a test signal source;

coupling said test signal source to said first wavelength division multiplexer, wherein said first wavelength division multiplexer introduces the optical test signal from said test signal source into the first of the two dedicated optical fibers.

3. The method according to claim 2, wherein said step of monitoring said optical test signal includes the substeps of:

coupling said first wavelength division multiplexer to the second of the two dedicated optical fibers;

providing an optical signal monitor;

coupling said optical signal monitor to said first wavelength division multiplexer, wherein said first wavelength division multiplexer removes said optical test signal from the second of said two dedicated optical fibers and directs said optical test signal into said optical signal monitor.

4. The method according to claim 3, wherein said test signal source, said optical signal monitor and said first wavelength division multiplexer are separate modules contained within a shelf of a fiber administration system at the central office of the telecommunication provider.

5. The method according to claim 4, further including the step of providing a shelf controller that is coupled to both said test signal source and said optical signal monitor.

6. The method according to claim 5, wherein said step of comparing the optical test signal introduced into the first of the two dedicated optical fibers to the optical test signal received from the second of the two dedicated optical fibers is performed by said shelf controller.

7. The method according to claim 2, further including the step of determining losses in said optical test signal introduced by said test signal source.

8. The method according to claim 1, wherein said step of monitoring said optical test signal includes the substeps of:

removing said optical test signal from the second of said two dedicated optical fibers; and

converting said test signal into a corresponding electrical test signal.

9. A system for testing a pair of dedicated optical fibers that extend from a central office of a telecommunications provider to provide signals at a first primary transmission frequency to a specific customer facility through an optical fiber network, said system comprising:

an optical test signal source for producing an optical test signal at a second frequency above or below the first primary transmission frequency and for introducing said optical test signal at the second frequency into a first optical fiber of said pair of optical fibers,

a wavelength division multiplexer located at or just prior to the customer facility, said wavelength division multiplexer being coupled to said pair of optical fibers, wherein said wavelength division multiplexer removes said optical test signal from said first optical fiber of said pair of optical fibers and loops said optical test signal at said second frequency removed from said first of said pair of optical fibers to the second of said pair of optical fibers to return said optical test signal to the central office of the telecommunications provider,

a monitor for receiving said optical test signal from the second of the two dedicated optical fibers at the central office, and

a comparator means for comparing the optical test signal introduced into the first of the two dedicated optical fibers to the optical test signal received from the second of the two dedicated optical fibers at the central office to determine losses in the two dedicated optical fibers.

10. The system according to claim 9, wherein said pair of optical fibers terminate at a fiber administration system in the central office of the telecommunications provider.

11. The system according to claim 10, wherein said optical test signal source and said monitor are modules that are mounted within a shelf of said fiber administration system.

12. An improved fiber administration system for an optical fiber network, wherein said optical fiber network includes at least one dedicated pair of optical fibers that carry signals of a first primary frequency between said fiber administration system and a specific customer facility through said optical fiber network, said fiber administration system comprising:

a frame, wherein said frame defines at least one bay;

at least one shelf contained within said at least one bay;

an optical transmitter module disposed within said shelf, wherein said optical transmitter module creates an optical test signal at a second frequency that is higher or lower than the first primary frequency;

a monitor module disposed within said shelf;

a first wavelength division multiplexing module disposed within said shelf, wherein said first wavelength division multiplexing module optically interconnects both said optical transmitter module to a first optical fiber of the dedicated pair of optical fibers, and said monitor module to a second optical fiber of the dedicated pair of optical fibers;

a second wavelength division multiplexer disposed at or near the specific customer facility, said second wavelength division multiplexer adapted to loop said optical test signal at said second frequency from said first optical fiber to said second optical fiber.

13. The fiber administration system according to claim 12, further including a shelf controller electronically coupled to both said optical transmitter module and said monitor module.

14. The fiber administration system according to claim 13, wherein said shelf controller reads data from both said optical transmitter module and said monitor module regarding said optical test signal.

15. The fiber administration system according to claim 12, wherein said optical transmitter module and said monitor module are contained within a common module housing on said shelf.