Monitoring system using an optical side tone as a test signal

摘要

An improved monitoring system for monitoring a fiber optic transmission system using optical side tones. The monitoring system includes a line monitoring equipment (LME) connected to a portion of an optical transmission system. The LME includes a pseudo-random sequence (PRS) tone generator for generating a PRS tone, a laser transmitter for transmitting an LME optical side tone based on the PRS tone. The LME includes a delay system for delaying the PRS tones, an optical filter for passing only the wavelength of the LME side tone. A plurality of data channels are transmitted over the system using WDM. A coupler is used to combine the WDM data with the LME side tone. A repeater having an optical loopback coupler returns a portion of the combined signal to the LME. The comparator/correlator correlates the delayed PRS tones with the LME side tone returned by each repeater.