理论研究电流注入对垂直腔面发射激光器多横模行为的影响

从包含时空变量的速率方程出发,针对弱折射率导引垂直腔面发射激光器(VCSELs),利用空间积分法分析了典型电注入参数对VCSELs多横模行为的影响,在不降低模型准确性的前提下提高了仿真效率。仿真结果表明,注入盘孔径和注入环越小、注入强度越低以及电流扩散越弱时,VCSELs更易实现单横模工作;反之,VCSELs高阶横模开始出现并呈现较强的模式竞争,引发了载流子空间烧孔效应,并导致基模强度降低。进一步得出,在环形注入方式下,高阶模式更容易出现且彼此间的竞争较盘形注入时强。     

应用于光抽运铯原子钟的小型稳频激光器（英文）

设计了一种应用于光抽运铯原子钟的稳频激光器,用小型化的饱和吸收装置对激光进行稳频,用于产生饱和吸收谱的泵浦光的偏振方向与检测光的偏振方向相互垂直,通过调节激光的偏振方向增大铯原子的跃迁几率.相对于一般简化的饱和吸收装置,小型化的饱和吸收装置产生的用于锁频的参考信号的幅度更大.当激光频率被锁定在铯原子的6S_(1/2),F=4→6P_(3/2),F=5能级跃迁线上时,对激光器的稳定度进行了测量,百秒稳定度为1.88×10~(-11).该稳频激光器的体积较小,有利于光抽运铯原子钟的小型化和工程化应用.     

Polarization switching and synchronization of mutually coupled vertical-cavity surface-emitting semiconductor lasers

Polarization switching (PS) dynamics and synchronization performances of two mutually coupled vertical-cavity surface-emitting lasers (VCSELs) are studied theoretically in this paper. A group of dimensionless rate equations is derived to describe our model. While analysing the PS characteristics, we focus on the effects of coupling rate and frequency detuning regarding different mutual injection types. The results indicate that the x-mode injection defers the occurrence of PS, while the y-mode injection leads the PS to occur at a lower current. Strong enough polarization-selective injection can suppress the PS. Moreover, if frequency detuning is considered, the effects of polarization-selective mutual injection will be weakened. To evaluate the synchronization performance, the correlation coefficients and output dynamics of VCSELs with both pure mode and mixed mode polarizations are given. It is found that performance of complete synchronization is sensitive to the frequency mismatch but it is little affected by mixed mode polarizations, which is opposite to the case of injection-locking synchronization.     

基于垂直谐振腔结构的半导体光放大器理论分析

由新型垂直腔半导体光放大器（VCSOAs）器件结构出发,在反射模式和透射模式两种 情况下,计算了VCSOAs的分布布拉格反射堆（DBR）反射率、单程增益与增益、带宽的关系 ,其中DBR反射率的增大伴随着增益的上升,但也伴随着带宽的减小.通过引入增益-带宽 积的概念,以均衡增益与带宽.计算中表明:10 dB以上增益,50 GHz以上带宽可以实现. 计算结果与文献实验相吻合,对优化VCSOAs的结构设计和性能有所裨益.     

Theoretical study on controlling nonlinear behaviors of a coupled-cavity VCSEL by external optical injection

A master-slave configuration used to control the nonlinear behaviors arising in a vertical cavity surface emitting laser (VCSEL) with strong external optical feedback is established. In terms of bifurcation diagram, time and frequency domain, the influence of the continuous optical injection from the master VCSEL on the nonlinear characteristics of the slave is investigated theoretically. For relatively weak injection, the slave still keeps its intrinsic nonlinear state. With increasing the injection strength, these nonlinear behaviors evolve to periodic fluctuation, and at last are replaced by the steady-state (e.g. the critical injection parameter for steady-state is 1.2 when external cavity's reflectivity and length are 4% and 4 cm, respectively). During this evolution the bifurcation-contraction phenomena are also observed.     

Theoretical study on controlling nonlinear behaviors of a coupled-cavity VCSEL by external optical injection

A master-slave configuration used to control the nonlinear behaviors arising in a vertical cavity surface emitting laser (VCSEL) with strong external optical feedback is established. In terms of bifurcation diagram, time and frequency domain, the influence of the continuous optical injection from the master VCSEL on the nonlinear characteristics of the slave is investigated theoretically. For relatively weak injection, the slave still keeps its intrinsic nonlinear state. With increasing the injection strength, these nonlinear behaviors evolve to periodic fluctuation, and at last are replaced by the steady-state (e.g. the critical injection parameter for steady-state is 1.2 when external cavity's reflectivity and length are 4% and 4 cm, respectively). During this evolution the bifurcation-contraction phenomena are also observed.     

基于线性光放大器的全光逻辑异或门理论分析

基于速率方程建立了线性光放大器(LOA)的数值模型,模拟了线性光放大器的增益钳制特性。与对称结构马赫曾德尔干涉仪(MZI)的传输矩阵相结合,构建了线性光放大器马赫曾德尔干涉仪全光逻辑异或门模型,实现了两路40Gbit/s信号的异或运算。与传统的半导体光放大器(SOA)构成的马赫曾德尔干涉仪型异或门进行了比较,从器件结构上对两种异或门运算结果的差异给出了解释。结果表明,线性光放大器具有平坦的增益特性,对输入信号的扰动具有不敏感性,垂直光场缩短了载流子恢复时间;线性光放大器马赫曾德尔干涉仪结构可以实现异或运算;利用差分相位法可以解决载流子恢复时间对信号处理速度的限制,合理地选择延迟时间能获得较好的运算结果;输出信号具有眼图张开度大、消光比高、峰值啁啾小、对波长变化不敏感等优点。     

激光器自发辐射噪声对混沌光通信系统的影响

构建了基于外光反馈的混沌光通信系统模型, 通过引入Langevin噪声源, 建立了包含自发辐射噪声特性的主从式速率方程. 利用所得数学模型, 研究了系统中可能存在的两类同步:全混沌同步和普通注入锁模型混沌同步; 分析了两端激光器自发辐射噪声对此二类同步以及系统收发两端混沌信号的影响; 最后,以2.5Gb/s伪随机数字调制下的混沌掩蔽方式为例,介绍了系统的加/解密过程以及噪声对系统解码性能的影响. 关键词： 混沌光通信 外光反馈 光注入 混沌同步 自发辐射噪声     

Theoretical study on phase conjugation in weakly injected vertical-cavity surface-emitting lasers

This paper gives a detailed theoretical investigation on phase conjugation induced by nearly degenerate fourwave mixing in single mode vertical-cavity surface-emitting lasers （VCSELs） with weak optical injection. Considering VCSELs that can work in linearly polarized or elliptically polarized states, it derives the theoretical expression of the conjugated field by small signal analysis based on the vectoral rate equations-the spin-flip model. For linearly polarized state, VCSELs show similar conjugate spectra to edge-emitting semiconductor lasers. For the elliptically polarized state, dichroism and birefringence parameters as well as the spin-flip rate can change the conjugate spectra. Especially, when frequency detuning of the probe and pump waves is between the positive and negative relaxation oscillation frequency, changes are evident. For specific values of parameters, conjugate efficiency between 20 dB to 40 dB are obtained.     

自旋激光器的动力学特性及应用研究进展

在半导体激光器中引入自旋极化载流子是实现室温自旋电子应用的新途径,其超越了常规的磁阻效应。自旋极化载流子的注入导致自旋激光器具有丰富的动力学行为并展示出包括高频偏振振荡和偏振混沌动力学等特性,使其在保密光通信、量子计算、光信息处理和数据存储、可重构光互联以及生物医学传感等领域具有巨大的应用潜力。梳理了近年来自旋激光器的动力学特性及其应用研究进展。介绍了自旋激光器丰富的动力学行为及混沌演变机制;随后分析了自旋激光器的高频振荡特性;归纳了基于自旋激光器动力学特性的最新应用研究进展。在此基础上,展望了自旋激光器的发展趋势和面临的挑战,为相关领域的研究和工程应用提供参考。