All-Optical 40-GHz to 40-GHz Switching by Cascade Second-Order Nonlinearities in a QPM-PPLN Device

We report characteristics of a QPM-PPLN-based all-optical switch through experiments considering the pulsewidths and the optical noises of the inputs. Although stable and efficient 40-GHz switching is achieved using a 3-cm-long device, clean clock input is required to produce a wavelength-converted output without excessive degradation.