Wavelength conversion employing 120-fs optical pulses in a SOA-based nonlinear polarization switch

We demonstrate wavelength conversion based on nonlinear polarization rotation driven by ultrafast carrier relaxation in an InGaAsP-InGaAs multiquantum-well semiconductor optical amplifier. We use a continuous-wave (CW) probe beam at a center wavelength of 1555 nm, and a control pulse of duration of 120 fs at a center wavelength of 1520 nm. We have investigated wavelength conversion for different injection currents and for different control pulse energies. We show that a conversion efficiency of 12 dB can be obtained for control pulse energies of 10 pJ.