基于MZI结构和级联SOA的宽相位容限全光异或门

A broad phase margin all-optical XOR logic gate based on cascaded SOAs in MZI

传统使用半导体光放大器(SOA)中交叉相位调制(XPM)效应构成全光逻辑异或(XOR)门的方案,由于受到单个SOA中XPM效应自身原理的限制,需要精确的相位控制。本文提出了一种基于马赫-增德尔干涉仪(MZI)和级联SOA中XPM效应实现全光逻辑异或门的新方案。本文方案使用对称的MZI结构,在两臂上分别放置两个级联的SOA,通过对时钟光的相位调制,达到对两级输入信号光进行XOR运算的目的。在40Gbit/s下的仿真结果表明,本方案易于调节,只需要两束输入信号光以相反比例分光,即可对其进行异或逻辑运算,在放宽了分光比取值范围的同时,也降低了对XPM效应中相位控制的要求,实现了宽相位容限的全光逻辑XOR门。研究了时钟光功率和输入信号分光比对逻辑运算结果的影响,发现输入信号分光比的不同步变化对输出信号质量的影响较为明显。对提高方案速率的方法进行了讨论。

Typical schemes that exploit semiconductor optical amplifier cross-phase modulation （SOA- XPM） to constitute all-optical XOR logic gate need to precisely control the phase of the MZI due to the inherent properties of XPM in SOAs. In this paper,a scheme of all-optical XOR logic gate based on MZI and XPM in cascaded SOAs is proposed. The scheme consists of a symmetrical SOA-MZI by putting two cascaded SOAs on both arms of the MZI,and the gate can be realized via the configuration and the injec- tion of the clock signal and two input signals. Numerical simulations at 40 Gbit/s demonstrate that the quality of the output is ensured as long as the splitting ratio of the two input signals is reversed. Since the splitting ratio can be varied in a large extent,this scheme provides the advantage of lowering the re- quirement in precisely controlling the phase when exploiting XPM in SOAs. Thus, al/-optical XOR logic gate with broad phase margin is constructed. Finally, we discuss the influence of clock pulse power and splitting ratio of input signals on logical operation results. It is found that asynchronous change of input signals＇ splitting ratio will relatively affect the quality of output signals. Besides, the methods to enhance processing speed are discussed.