scope:

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-tonoise 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.