Raman effect in AlGaAs waveguides for all-optical applications

By measuring the absolute Raman scattering cross section, we obtain the low-frequency depolarized Raman gain spectrum in Al0.24Ga0.76as at a pump wavelength of 1.55 µm. We develop a model that shows that the Raman effect leads to cross talk between orthogonally polarized subpicosecond pulses and to spectral distortion. For example, for π-phase-shift conditions, the Raman effect causes a 30% energy exchange between orthogonally polarized 300-fs pulses. Therefore, the Raman effect limits the performance of semiconductor waveguides using subpicosecond pulses in all-optical switching or quantum-optics applications.