Consider a tunable 22 MZI that is constructed on an electro-optical crystal having an effective index of 1.5. (a) If the MZI is used to combine two wavelength channels separated by 0.2 nm, find the required AL if the wavelength is centered at 1550 nm. (b) Assume the parameter AL is varied by electrically modulating the refractive index of the electro-optical crystal. What is the index change needed if the waveguide length is 100 mm?