System and method for testing optical fibers that lead between a telecommunications provider and a customer's premises

• US 6,317,535 B1
• Filed: 08/24/1999
• Issued: 11/13/2001
• Est. Priority Date: 08/24/1999
• Status: Expired due to Fees

• Current Assignee: Fitel USA Corporation (Furukawa Electric Company Limited)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Jennings, Mark Richard, Leone, Frank Salvatore, Pimpinella, Richard Joseph
• Primary Examiner(s): Bovernick, Rodney
• Assistant Examiner(s): CONNELLY, MICHELLE R
• Application Number:
  US09/379,858
• Time in Patent Office: 812 Days
• Field of Search: 385/24, 385/100, 385/134, 385/137, 356/73.1, 359/124-127, 359/173
• US Class Current: 385/24
• CPC Class Codes: G01M 11/3136 for testing of multiple fibers
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: H04B 10/071 using a reflected signal, e.g. using optical time domain reflectometers [OTDR]

Abstract

A system and method for testing the integrity of a pair of optical fibers that are received by a specific customer facility through the optical fiber network of a telecommunications provider. In one embodiment, the system contains a monitor and test access module including a wavelength division multiplexer for each pair of optical fibers that lead to a customer facility and an optical tap and monitoring circuit for monitoring the optical signal transmitted from the customer facility. Monitoring of the optical signal generated from the customer location gives an indication of the general quality of the fiber optic connection. A remote fiber test system that includes an optical time domain reflectometer can be coupled through the monitor and test access module. The optical fibers can be tested one at a time, or the two optical fibers leading to the same customer facility can be looped together and tested at the same time. Alternately, an optical test signal source for producing said optical test signal and an optical signal monitor for detecting the optical test signal can be routed through the monitor and test access module.

Claims

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

providing a first and second wave division multiplexer at said central office, each wave division multiplexer coupling to one of said two dedicated optical fibers prior to entering a fiber optic transmission system at said central office, wherein said second wave division multiplexer couples to an optical test port;

providing an optical tap at said central office between said first wave division multiplexer and said fiber optic transmission system for tapping off a portion of a transmission signal received from said customer facility;

electronically monitoring said transmission signal received by said optical tap, wherein a trouble signal is indicated when said transmission signal falls below a given threshold;

introducing an optical test signal into a first of the two dedicated optical fibers at the central office of the telecommunications provider;

looping said optical test signal from the first of the two dedicated optical fibers to a second of the two dedicated optical fibers at the customer facility; and

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

2. The method of claim 1, wherein a third and fourth wave division multiplexer are coupled to each of said two dedicated optical fibers at said customer facility to prevent said test signal from entering fiber optic transmission equipment at said customer facility, one end said third and fourth wave division multiplexer being optically coupled to one another to accomplish loop back of said optical test signal.

3. The method of claim 2, wherein said third and fourth wave division multiplexer are included in a single module.

4. The method of claim 1 wherein said optical test signal is an OTDR test signal.

5. The method of claim 1 wherein said test signal is generated from an optical test signal source for producing an optical test signal and said optical test signal is received by an optical signal monitor for detecting said optical test signal.

6. The method of claim 5, wherein OTDR test signals are launched over spare fibers.

7. The method of claim 1, wherein monitoring of said optical test signal and said transmission signal received from said customer facility is accomplished in a fiber administration system.

8. In a telecommunications system where two dedicated optical fibers extend from a central office of a telecommunications provider to a customer facility through an optical fiber network, a system for remotely testing the two optical fibers, the system comprising:

a first and second wave division multiplexer at said central office, each wave division multiplexer coupling to one of said two dedicated optical fibers prior to entering a fiber optic transmission system at said central office, wherein said second wave division multiplexer couple to an optical test port;

an optical tap at said central office between said first wave division multiplexer and said fiber optic transmission system for tapping of a portion of transmission signal received from said customer facility;

an optical monitoring circuit for electronically monitoring said transmission signal received by said optical tap, wherein a trouble signal is indicated when said transmission signal received given threshold;

means for introducing an optical test signal into a first of the two dedicated koptecal fibers at the central office of the telecommunications provider, wherein said optical test signal from the first of the two dedicated optical fibers is looped to a second of the two edeicated optical fibers at the customer facility; and

means for monitoring said optical test signal on the second of the two dedicated optical fibers at the central office.

9. The system of claim 8, wherein a third and fourth wave division multiplexer are coupled to each of said two dedicated optical fibers at said customer facility to prevent said test signal from entering fiber optic transmission equipment at said customer facility, one end of said third and fourth wave division multiplexer being optically coupled to one another to accomplish loop back of said optical test signal.

10. The system of claim 8, wherein said optical test signal is an OTDR test signal.

11. The system of claim 8, further including an optical test signal source for producing said optical test signal and an optical signal monitor for detecting said optical test signal.

12. The system of claim 11, wherein a monitor and test access module, said test signal source and said optical signal monitor are separate modules contained within a shelf of a fiber administration system at the central of the telecommunication provider.