Method and device for monitoring branched optical line network

• US 5,452,075 A
• Filed: 12/06/1994
• Issued: 09/19/1995
• Est. Priority Date: 07/03/1992
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Edwall, Nils E. G.
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US08/354,145
• Time in Patent Office: 287 Days
• Field of Search: 356/73.1, 250/227.15
• 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 method for monitoring branched optical line networks, adapted for transferring information signals via one or more branchings between an information source and an information receiver. The information signal is fed to a first in-gate to its respective branching and that a monitoring signal is fed into a second in-gate to its respective branching and that the branching connects the information signal and the monitoring signal to a first as well as to a second out-gate of the branching.

Claims

1. A method for monitoring branched optical line networks, adapted for transferring information signals via one or more branchings between an information source and an information receiver, comprising the steps of:

feeding the information signal to a first in-gate of at least one branching;

feeding a monitoring signal into a second in-gate of said at least one branching, wherein the branching connects the information signal and the monitoring signal to a first and second out-gate of the branching;

cascade-coupling a plurality of branchings in such a way that the first information signal is connected via the first in-gate and both out-gates of each branching to the first in-gate of each subsequent branching;

connecting the monitoring signal via the second in-gate and both out-gates of each branching to the first in-gate of each subsequent branching;

monitoring the entire line network in the feed direction of the information signal from the first branching with the monitoring signal; and

transferring the monitoring signal upon a detected abnormal state in the line network to the second in-gate of each subsequent branching in which an abnormal state has been detected.

2. A device for monitoring branched optical line networks, adapted for transferring information signals via one or more branchings between an information source and an information receiver and comprising a monitoring device connected to the line networks, said branchings consists of at least two in-gates and at least two out-gates, and at least one of the in-gates is connected for receiving the information signal and the second in-gate is connected for receiving a monitoring signal from the monitoring device and the branchings are adapted to connect the in-gates to the out-gates so that both the information signal and the fed monitoring signal are transferred to the first as well as to the second out-gate, wherein a plurality of branchings are cascade-coupled in such a way, that the out-gates from each branching are connected to an in-gate of subsequent branchings, subsequent branching being connected in cascade after the first branching, while a second in-gate of each branching is connectable to the monitoring device.