【作者】 李茜；

【导师】 潘炜；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2008， 硕士

【摘要】 全光逻辑门是实现光分组交换、光计算和未来高速大容量光传输的关键器件,其发展对未来的光分组交换、光计算和光传输等方面具有十分深远的影响。交叉增益调制(XGM)型波长转换的技术具有输出信号啁啾(Chip)小、信噪比(SNR)高、消光比(ER)高、便于集成等优点,具有良好的商业化前景。目前主要对基于半导体光放大器(SOA)的XGM来实现逻辑门作了大量研究。然而,一种新的线性光放大器(LOA)因为其良好的线性增益特性,十分适合用作实现波长转换以及全光逻辑功能,比传统的SOA更能实现大容量、高速率的信息处理。本文主要对基于LOA-XGM的一些基本特性以及作为全光逻辑门进行了研究。首先从速率方程出发,构建了LOA-XGM的基本理论模型,利用该模型对LOA的增益特性、消光比特性以及啁啾特性进行详细分析;然后,在XGM的基础上,利用Simulink对级联LOA建模,数值模拟实现了全光逻辑或非运算功能,分析了不同注入电流的组合对于逻辑输出结果的影响;最后,利用Simulink建模便于模块修改的优点,在逻辑或非门模型的基础上,搭建了逻辑与门的模型,分析了LOA每个子段的有源区内载流子浓度随时间的变化以及不同输入参数对于逻辑输出结果的影响,以达到优化设计的效果。研究结果表明:(1)由于垂直光场的增益钳制作用,LOA的增益波动范围比SOA小、增益恢复时间短;减小探测光功率以及选择合适的波长间隔和注入电流都有利于获得较大的消光比。但是,在一定范围内减小探测光功率和增加抽运光功率也会造成啁啾的增大,因此合理的选择这些参数,能够达到消光比与啁啾之间的平衡。(2)LOA进行逻辑或非运算时,由于其线性增益特性,使得输出信号所产生的畸变比利用SOA进行逻辑运算时小;适当的选择级联LOA的工作电流组合,有利于改善最后的逻辑输出结果。(3)LOA进行逻辑与门运算时,适当的选择输入探测光波长和抽运光波长范围,以及适当的增加抽运光A的光功率,都有利于改善最后的逻辑输出结果;再与SOA的逻辑输出结果做了比较,进一步证明了LOA的性能优于SOA。更多还原

【Abstract】 All optical logic is the key devices of optical packet switching system, optical calculation and great capacity transmission which should be influenced heavily in the future. Cross-gain modulation (XGM) have many advantages, such as small chirp, high signal noise rate (SNR) , high extinction rate (ER) and convenient for integration. At present, many researches of logic gate which based on XGM of semiconductor optical amplifier (SOA) have been done. However, because of the linear gain characteristic, LOA is quite suit for wavelength conversion and optical logic function, and achieving higher capacity and rate information processing than traditional SOA.The basic characteristics and logic gate of LOA was studied. Firstly, a theoretical model of LOA-XGM is established based on velocity equation, The gain, extinction rate (ER) and chirp characteristics are analyzed particularly using this model. Secondly, based on XGM, numeral simulation realized the output results of logic NOR operation, using Simulink for setting up a model of connect. LOA is presented to the influences of output results with the different input current group. Finally, based on logic NOR gate, a model of all-optical logic AND gate is presented, with the excellence of the Simulink modeling, which is convenient for amending. The carrier consistency is changed with time and the influences of output results with different parameters of LOA are analyzed, they are used for the purpose of optimizing design.The results show that owing to the existence of vertical-cavity laser (VCL), the gain fluctuation of LOA is smaller than SOA’s, also the gain recovery time is shorter. Lower probe power and suitable wavelength spans, which between pump and probe, and the input current have the advantages to achieve the higher output ER. But lower probe power and higher pump power in certain spectrums can also increase chirp, so suitable choice of these parameters can achieve balance of ER and chirp. The distortion of all-optical logic operation of LOA is smaller than all-optical logic operation of SOA. Proper input current groups have the advantages to achieve better logic operation effect. In the logic AND operation of LOA, proper wavelength scope of probe and pump, and higher power of the input signal A have the advantages to achieve better logic operation effect. Compared with the output results of SOA, it is further proved that the capability of LOA is more excellent than SOA.更多还原