We study the instantaneous nonlinear index change in Al 0.2Ga0.8As waveguides below the two-photon absorption edge and find π phase shifts with 80 pJ, 0.4 ps pulses at wavelengths near 1.6 μm. These large phase shifts are obtained with less than 1 dB of loss from multiphoton absorption. Our results indicate that AlGaAs waveguides, which have a mature fabrication technology, can be used as compact nonlinear elements in switching and quantum optics applications in the near-infrared. Further optimization of the waveguide geometry should result in useful nonlinear phase shifts and low losses for pulse energies approaching a picojoule.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)