Amodulator is required to modulate light at 40ghz. (a) what is the maximum length that the modulator can have to do this task if the refractive index is n 2.2 (b) assuming that this length of crystal is not sufficient to create a phase shift at the maximum achievable electric field strength, can you think of a more sophisticated electrode arrangement which allows the driving field and the propagating light to stay in phase over a longer length?