全光或门是全光逻辑信号处理中必不可少的一项基础技术, 以往采用周期性极化铌酸锂（PPLN）波导实现的全光或门的输出光波均是混频波。本文基于PPLN波导的和频+差频效应（SFG+DFG）, 在准相位匹配条件下, 通过三个PPLN波导的级联设计实现了单波长输出的全光或门。通过数值计算和仿真得到了信号波形和眼图, 并通过计算消光比、脉冲宽度以及峰值功率的延迟时间分析了单波长全光或门的性能。结果表明, 本方案能很好地实现单波长输出的全光或门, 其输出光波能直接应用于光域, 从而改善光逻辑器件的衔接, 提高处理速度, 并为研发新型全光逻辑器件提供重要基础。

All-optical OR gate is a necessary basic technology in all-optical logic signal processing, and the output optical wave of the OR gate based on periodically poled lithium niobate (PPLN) waveguide in former schemes is mixing wave. In this paper, the all-optical OR gate with single wavelength which consists of three cascaded PPLN waveguides is proposed based on sum-frequency generation and difference-frequency generation (SFG+DFG) in quasi-phase-matching consideration. The signal waveforms and eye-diagrams are obtained by numerical calculation and simulation, and the performance of all-optical OR gate with single wavelength is analyzed by the parameters such as extinction ratio, pulse width and delay time of peak power. The results demonstrate that the logic function of OR gate with single wavelength can be achieved well by this configuration, so that its output optical wave can be used directly in optical domain, thus the connection of optical logical devices can be improved, the speed of processing can be increased, and the critical foundation of developing new all-optical logical devices can be provided.