Abstract

In the efforts of achieving nonlinear directional coupling in semiconductors, two-photon absorption (2PA) was found to produce a limitation on switching efficiency.^1,2 To release this limitation, wavelengths beyond the half band gap can be used for minimizing 2PA. For example, wavelengths >1.5 μm can be used for nonlinear directional couplers made of AGaAs. However, with diminishing 2PA three-photon absorption (3PA) becomes a new limiting factor for nonlinear coupling. In terms of normalized parameters, the equation governing the light coupling is

© 1992 Optical Society of America