Patent ID: 6327250
Filing Date: 2001-12-04
Classification: H04B

Abstract:
A method for monitoring an optical transmission path through an optical transmission system supporting bi-directional communication between first and second terminals along first and second optical transmission paths, said first transmission path including an optical amplifier located therein, said method comprising the steps of:a. generating a test signal that is formed by superposition of first and second optical tones located at first and second wavelengths, respectively, within the bandwidth of the optical amplifier;b. arranging an amplitude and phase of said first and second optical tones such that said test signal has a substantially constant intensity over a modulation cycle of said first and second optical tones;c. transmitting from the first terminal said test signal along the first optical transmission path and through the optical amplifier;d. receiving at the first terminal a portion of the test signal after it traverses the optical amplifier, an optical loop-back path, and a second transmission path.