Spectral characterization of the linear and quadratic electro-optic effects in GaAs/AlGaAs multiple quantum well waveguides

The electro-optic effect in GaAs/AlGaAs multiple quantum well stripe waveguides has been studied extensively for both TE and TM polarization in a spectral range close to the excitonic band edge. The effect has been resolved into two components, a linear electro-optic (LEO) effect and a quadratic electro-optic (QEO) effect. The LEO coefficients r 63 and r 33 have been measured to be -1.75*10 -12 m V -1 and zero respectively, similar to that of bulk GaAs, with no significant wavelength dependence. The quadratic effect, however, has been shown to be highly wavelength-dependent and enhanced compared with bulk GaAs. A QEO coefficient as large as 140*10 -20 m 2 V -2 has been measured at photon energies 28 meV from the lowest energy exciton. The spectral dependence of the quadratic effect has been studied for both TE and TM polarization.