This part of IEC 61280 defines the averaged Q-factor and provides a procedure to measure it
by using amplitude histogram parameters such as the standard deviation and average level.
The averaged Q-factor and amplitude histogram parameters are useful for monitoring changes
in optical signal quality in installed optical networks. The average Q-factor is correlated with
the traditional Q parameter of a given optical channel.
With the averaged Q-factor test method signal, quality degradations due to optical signal-to-
noise ratio (OSNR) degradation and to waveform distortion can be monitored:
- OSNR degradation, due to the following causes:
- accumulation of amplified spontaneous emission (ASE);
- transmission line loss;
- channel crosstalk;
- waveform distortion, due to the following causes (usually simultaneously present):
- chromatic dispersion;
- polarization mode dispersion (PMD);
- optical nonlinear effects.