Guilin Sun
Ansys Employee

Please check the transient simulation in CHARGE where it usually applies a step function to get the rise time. Even if you have a triangle pulse voltage applied, at each value of voltage, the index change induced is the same as at the steady state of the same voltage, since from voltage change to index change it is instant, compared with the electric response. therefore no need to get the index change at each voltage, and it is not the optics that affects the modulator speed. it is the electric signal.

If you want to know the index change at each voltage, you can simulate the steady state.

Your feature reuqest has been discussed already.