For the current case study, the overall performance is good, although the 15% impedance mismatch results in fluctuations in BER on the order of 5 decades. This is a large performance fluctuation. The corresponding histogram on the right can be interpreted as an estimated yield for over 100 manufacturing runs for a given performance threshold.
Finally, we consider one more factor affecting the speed of modulation: the RF losses . Due to the skin effect, electrode resistance grows with the frequency of the modulating signal. This, together with its influence on impedance mismatch, can significantly impact the modulation bandwidth. Figure 7 shows extinction ratio measured from an optical eye at the TW-MZM output due to 10% fluctuations in RF losses.