Polarization-dependent carrier dynamics in quantum dot semiconductor optical amplifiers for all-optical wavelength converter

초록

We examine ultrafast nonlinear birefringence of femtosecond optical pulses propagating a semiconductor optical amplifier whose active element is composed of InAs/InP quantum dots at about 1.55 m. Polarization-sensitive carrier dynamics in quantum dots are modeled for nonlinear gain bleaching that is employed for nonlinear birefringence for all-optical wavelength converters. Nonlinear absorption and spectral hole-burning are included in this work, by using three-coupled rate equations for carrier dynamics with a beam propagation method. It is revealed that quantum dots support ultrafast nonlinear gain bleaching for ultrafast birefringence that is used in ultrafast all-optical wavelength converters. In particular, we focus on the investigation of pump-pulse-energy dependence of ultrafast nonlinear birefringence for all-optical wavelength converter, enabling optical condition for a well-shaped converted signal to be determined.