All-optical demultiplexing using LiNbO3 quasiphase-matched wavelength converters

All-optical demultiplexing based on the cascaded chi ((2)) process in a LiN bO3 quasi phase-matched wavelength converter is studied. Based on the obtai ned fundamental pulse width dependence of the normalized second harmonic ge neration (SHG) efficiency, it is predicted that efficiency of the cascaded chi ((2)) wavelength conversion can be enhanced greatly using a pump light with a short pulse. This prediction is verified by an experimental demonstr ation of demultiplexing from 40 GHz to 10 GHz. Despite the low average pump power (similar to1 mW, 3.4 ps pulse width) used in this experiment, conver sion efficiency as high as -17 dB was obtained. It is also found that the b roadening of the converted pulse width is negligible in the present demulti plexing method.