Measuring the signal quality in digital optical fiber transmission networks by evaluating the signal histogram

摘要

The invention relates to the area of optical fiber communications systems, in particular, to the difficulty of monitoring signals in transparent optical networks (all-optical networks) which are systems without digital intermediate regeneration. In order to calculate the bit error probability (BEP), the signal is demodulated, sampled and an amplitude histogram is generated. This serves primarily to modulate signal distortions. For each state of the signal (logic "0" or "1"), a family of amplitudes which represent the mean value of a noisy sub-signal is determined from the histogram. The variance of the individual noisy signal superimposed on each amplitude value is calculated from the parameters of the receiver as well as from the optical signal-to-noise-density ratio (OSNR). The bit error probability can be calculated in a sufficiently precise manner from these parameters.