Abstract

Semiconductor quantum-well structures can provide enhanced nonlinear effects compared to those observed in bulk material. The largest irradiance-induced refractive changes occur at wavelengths nearly resonant with the band edge or exciton absorption. If such a nonlinearity is to be effectively exploited in a waveguide configuration, the absorption due to the active quantum-well layers must be diluted to ensure sufficient transmission. Although this produces, all else being equal, a proportional drop in the effective nonlinearity (n₂), it does permit operation at, or near to, the optimum wavelength where the figure-of-merit n₂/α is maximized. In addition to the possible device potential of nonlinear optical waveguides, this configuration also permits investigation of the nonlinearity using light polarized both parallel (TE) and perpendicular (TM) to the quantum well. We present here measurements of nonlinear absorption and refraction, associated with electron-hole pair excitation, in an InGaAs Single Quantum Well (SQW) centered within a strip-loaded, non-absorbing InGaAsP waveguide.

© 1991 Optical Society of America