Asymmetric Quantum Well Structures Possessing Large Second Order Optical Nonlinearities

Nonlinear optical properties of quantum wells (QW’s) and superlattices (SL’s) 1,2 are attracting increasing interest. Calculations and observations of strong third-order nonlinearities were reported in GaAs-GaAlAs QW and SL structures. Among the phenomena mentioned as leading to large values of x(3) in such structures are conduction band nonparabolicity 3,4, exciton line saturation 5 and the quantum confined Stark effect (QCSE) 6,7. Practical devices using QCSE, the so-called self-electrooptic effect devices, or SEED’s have been successfully demonstrated 8.