Comparison of DFG and the cascaded χ~((2)) based wavelength conversions using MgO doped LiNbO_3 QPM waveguides

摘要

Different frequency generation (DFG) and the cascaded second-order nonlinear interaction (χ~((2))) based wavelength conversion in 5-mol % MgO doped LiNbO-3 QPM waveguides are studied and compared both experimentally and theoretically for the first time. It is shown that DFG based wavelength conversions have a higher conversion efficiency; while the cascaded χ~((2)) based wavelength conversions have a wider 3-dB signal conversion bandwidth. It is also exhibited that the simulations are consistent well with the experimental results. tolerance of pump wavelength for the cascaded χ~((2)) based wavelength conversion is twice as large as that of DFG based devices. These results are very helpful in choosing suitable wavelength converters for practical optical communication systems according to the system requirements.