Synchronization of chaotic vertical-cavity surface-emitting lasers (VCSELs) is achieved by external chaotic signal modulation successfully. Simulation indicates that we can get chaos synchronization if the intensity of external chaotic signal is large enough. First of all, we use direct current modulation to achieve the chaos of VCSELs, and determine the laser’s chaotic state by analyzing time series of the output and the corresponding power spectrum. And then we achieve synchronization of the two chaotic systems by external chaotic signal parameter modulation. We also find that the larger the modulation intensity is, the easier it is to achieve synchronization for chaotic VCSELs. This approach can also be applied to systems with a number of modulated lasers.

利用数值模拟的方法研究了电流调制下偏置电流和调制频率对垂直腔面发射半导体激光器(VCSEL)混沌动力学特性的影响。数值模拟结果表明, 在一定的调制频率下, 偏置电流较大时VCSEL处于稳定的周期一态, 偏置电流较小时激光器在调制参数的某些区间会出现阵发混沌; 在一定的偏置电流下, 调制频率较小时, VCSEL处于稳定的周期一态, 调制频率较大时系统在调制参数的某些区间会出现阵发混沌。所以偏置电流和调制频率是影响VCSEL混沌动力学特性的重要参数, 可以通过适当控制偏置电流和调制频率找到系统的周期态和混沌态。

文中首次运用R-矩阵方法,在三态密耦近似下计算了类锂离子C^{3+激发态(1s22p)2P光电离截面,主要给出了不同过程和不同分波的光电离截面.计算结果显示了光电离过程中非常丰富的Rydberg系列共振结构.}

本文首次运用R-矩阵理论方法,分别在单通道近似和三态密耦近似下计算了离子N²⁺基态(1s²2s²2p) ²P的不同过程、不同分波的光电离截面及各分波的光电离截面随有效量子数的变化规律.在三态密耦近似下,由于大量的自电离态与连续态的相互作用,计算结果显示了光电离过程中非常丰富的Rydberg系列共振结构,是以前的理论计算中所从未涉及到的.