High-speed quadratic electrooptic nonlinearity in dc-biased InP

We present experimental data on degenerate four-wave mixing as well simulation results of fast optical nonlinearities in highly excited semiconducting InP under applied dc-field. Hot-electron transport governed enhancement of optical nonlinearity is obtained by applying a dc-field of 10-14 kV/cm at full-modulation depth of light-interference pattern. The hydrodynamic model, which incorporates both free-carrier and photorefractive nonlinearities is used to explain the experimentally observed features. We show that the enhancement of optical nonlinearity is due to the quadratic electrooptic effect. (author)