Wavelength dependence of high-performance AlGaAs/GaAs waveguide phase modulators

The wavelength dependence of doped, reverse-biased channel waveguide phase modulators with very high efficiencies are reported between 1.06 ¿m and 1.53 ¿m. Figures-of-merit ranging from 61°/V mm and 40°/V mm to 27°/V mm and 16°/V mm for the TE and TM modes, respectively, have been obtained. By deducting the easily calculated linear electro-optic and free-carrier plasma effects, the data gives the first real measure of the dispersion associated with the shift in the absorption edge. This dispersion, which is the primary contribution to the quadratic electro-optic effect in semiconductors, accounts for more than half of the measured phase shift at 1.06 ¿m with the doping level used.