Method of identifying an optical cable

• US 5,331,392 A
• Filed: 07/24/1992
• Issued: 07/19/1994
• Est. Priority Date: 11/30/1990
• Status: Expired due to Fees

• Current Assignee: Furukawa Electric Company Limited
• Original Assignee: Furukawa Electric Company Limited
• Inventors: Sentsui, Shintaro, Fujisaki, Akira
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): CRAWFORD, LESLIE
• Application Number:
  US07/915,813
• Time in Patent Office: 725 Days
• Field of Search: 356/73.1, 250/227.17
• US Class Current: 356/73.1
• CPC Class Codes: G01M 11/31 with a light emitter and a light receiver being disposed at the same side of a fibre or waveguide end-face, e.g. reflectometers
• CPC Class Codes: G02B 6/562 locatable, e.g. using magnetic means

Abstract

A method of identifying a particular optical cable C1 out of a set of optical cables C1, C2 by applying an external signal by means of a signal applying apparatus 16 while an optical signal is transmitted from means for transmitting optical signals and monitoring changes in the signals received by means for receiving optical signals. Since the difference in the frequencies and the levels of the higher harmonics generated by the external signal in the particular cable and the other cable(s) that are laid so close to one another that the phenomenon of cross talk remarkably appears, the optical cable in question can be identified almost without fail.

Claims

1. A system for identifying a particular optical cable among a plurality of adjacent optical cables, the system comprising:

transmitting means for transmitting optical signals in the form of polarized light through the plurality of optical cables;

receiving means for receiving optical signals transmitted through the plurality of optical cables;

means for sequentially applying mechanical vibrations at a predetermined frequency to each of plurality of optical cables, one optical cable at a time, at an intermediary point along a length of optical cables concurrently with transmission of optical signals by said transmitting means, thereby modulating optical signals in the optical cable to which the mechanical vibrations are applied, and any adjacent optical cables;

means for identifying a particular optical cable among the plurality of optical cables by detecting the optical signals received by said receiving means and comparing levels of higher harmonics modulated optical signals in the particular cable with higher harmonics of modulated optical signals in the remainder of the plurality of optical cables, the particular optical cable being identified by the cable with the greatest level of higher harmonics of modulated optical signals.

2. The system of claim 1, wherein said transmitting means and said receiving means are connected to common ends of said plurality of optical cables.

3. The system of claim 1, wherein said transmitting and receiving means are connected to opposite ends of said plurality of optical cables.

4. A method for identifying a particular optical cable among a plurality of adjacent optical cables, the method comprising the steps of:

transmitting optical signals in the form of polarized light through the plurality of optical cables;

receiving optical signals transmitted through the plurality of optical cables;

sequentially applying mechanical vibrations at a predetermined frequency to each of a plurality of optical cables, one optical cable at a time, at an intermediary point along a length of optical cables concurrently with transmission of optical signals, thereby modulating transmitted optical signals in the optical cable to which the mechanical vibrations are applied and any adjacent optical cables;

identifying a particular optical cable among the plurality of optical cables by comparing levels of higher harmonics modulated optical signals in the particular optical cable with higher harmonics of modulated optical signals in the remainder of the plurality of optical cables, the particular optical cable being identified as the cable with the greatest level of higher harmonics of modulated optical signals.