Method and apparatus for detecting malfunctions in communication systems

An apparatus for detecting malfunctions on an optical device in a network comprising:

• an optical processing unit having a first input port coupled to an input port of the optical device and a second input port coupled to the output port of the optical device;
• an optical to electrical signal converter having an input port coupled to an output port of said optical processing unit and having an output port;
• and
• an electronic processing unit having an input port coupled to the output port of said signal converter and having an output port coupled to an alarm port of said apparatus.

A method for detecting the presence of a listening tone on a channel of an optical device having a plurality of channels, comprising the steps of:

• coupling to an optical processing unit a portion of an input signal of the optical device;
• coupling to the optical processing unit a portion of an output signal from the optical device, the output signal being associated with the same channel as the input signal;
• subtracting the portion of the input signal from the portion of the output signal to generate a difference signal;
• and
• providing the difference signal to a network management system.

An optical comparator for comparing an input signal of an optical device with an output signal from the optical device, comprising:

• (a) a first polarization controller having an input port receiving a portion of the input signal and having an output port;
• (b) a second polarization controller having an input port receiving a portion of the output signal and having an output port;
• and
• (c) an optical hybrid having a first input port coupled to the output port of said first polarization controller, a second input port coupled to the output port of said second polarization controller, and a plurality of output ports.