Energy harvesting in silicon wavelength converters.

Nonlinear loss is the central problem in silicon devices that operate using nonlinear optical effects. Wavelength converters are one example of such devices, wherein high optical intensities required for nonlinear interactions cause two-photon absorption and severe free-carrier absorption. In this paper, we report the first demonstration of nonlinear photovoltaic effect in silicon wavelength converters. This useful phenomenon allows us to eliminate the nonlinear loss caused by free-carrier absorption, while harvesting the optical power that is normally consumed by two-photon absorption.