中文摘要：

基于周期极化反转铌酸锂（PPLN）光波导级联倍频和差频（SHG＋DFG）的二阶非线性效应,提出并实验研究了皮秒脉冲的可调谐波长转换以及单信道到双信道的波长转换.信号光采用重复频率为40 GHz,脉宽为1.57 ps的脉冲信号.连续抽运光由光纤环形腔激光器（FRL）提供.不同于传统的SHG＋DFG型波长转换,信号光固定在PPLN光波导倍频过程的准相位匹配（QPM）波长处,通过调节抽运光的波长实现了转换空闲光的可调谐输出.当使用两个抽运光时实验观察到了单信道到双信道的波长转换.

英文摘要：

Based on cascaded second-harmonic generation and difference frequency generation （SHG＋DFG） in periodically poled LiNbO3 （PPLN） waveguides, tunable wavelength conversion as well as single-to-dual channel wavelength conversion are proposed and experimentally investigated. A picosecond pulsed signal with 40 GHz repetition rate and 1. 57 ps pulse width is adopted. The continues wave （CW） pump is provided by use of a fiber ring laser （FRL）. Different from the conventional SHG＋DFG-based conversion schemes, here the center wavelength of the signal is set at the quasi-phase matching （QPM） wavelength for the SHG process. By adjusting the pump wavelength, a tunable converted output idler wave is achieved. Moreover, single-to-dual channel wavelength conversion is also successfully observed by employing two pumps.