Effect of partially polarized amplified spontaneous emission noise on Q-factor estimation using optical signal-to-noise ratio

We report on the effect of the partially polarized amplified spontaneous emission noise on the Q-factor estimation by using optical signal-to-noise ratio. The result shows that this effect is negligible even in a long-distance transmission system (number of spans: <40) as long as the polarization-dependent loss per span is smaller than 0.2 dB