Measuring optical signal quality in wavelength multiplexed communication channels, using signal difference obtained by subtracting adapted test and reference signals

摘要

Optical signal quality is measured using a method comprising the following steps : (a) transmitting a test signal via the channel whose optical signal quality is to be measured ; (b) generating a reference signal ; (c) drawing off the transmitted signal and combining it with the refence signal at essentially the same location ; (d) converting the test and reference signals ; (e) detecting comparable signal sections in the respective signals ; (f) synchronising the signals ; (g) comparing the test and reference signals ; (h) adapting signal performance for the test and reference signals ; (i) generating a signal difference by subtracting the adapted test and reference signals ; and (j) providing an output value representing the effect of the channel on signal quality. An Independent claim is also included for the device used to carry out this method.