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。     

高效液相色谱法测定淤泥和土壤中双酚A、壬基酚和辛基酚

建立高效液相色谱法测定土壤和淤泥中双酚A、壬基酚和辛基酚.样品采用超声波萃取,以体积比1∶1的正己烷和丙酮作为提取剂,体积比90∶10的乙腈和水作为流动相,经SupelcosilTM LC PAH色谱柱(250×4.6 mm,5 μm)分离后荧光检测器检测,双酚A、壬基酚和辛基酚的荧光激发波长是227 nm,发射波长为313 nm,样品在6 min中内完全出峰.该方法的线性范围在0.1～20 μg/mL之间,在0.1μg/mL、0.5μg/mL和1.0 μg/mL3个浓度的添加水平下土壤和淤泥样品的加入回收率分别在83.7％～115.6％之间和94.3％～106.2％之间.该方法简单、快速和经济,可用于淤泥和土壤实际样品检测.     

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.     

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