Impact of fast transient power excursions on the performance of optical networks due to receiver constraints

A study is performed to quantify the influence of power excursions on system bit-error-rate performance. It is shown that the major degradation in the case of power excursions is due to receiver constraints, such as the AC coupling and the threshold misalignment. The impact of the high-pass frequency of AC-coupled receivers is discussed and the performance for receivers having different high-pass cut-off frequency is presented. The experimental characterisation that was performed using a novel setup includes time resolved Q-factor and bit-error-rate measurements in response to fast power changes. It was found that the penalty is greater for faster and larger excursions and it is more significant during a decrease in power than an increase of the same magnitude.