The principle of all-optical wavelength conversion based on the cascaded sum and difference frequency generation (SFG+DFG) in quasi-phase-matched (QPM) periodically poled LiNbO3 (PPLN) waveguides is introduced.

• 介绍了基于准相位匹配周期极化反转铌酸锂光波导的和频与差频(SFG+DFG)级联型全光波长转换技术的基本原理。