In this paper, we describe a new method to improve fast-light transmission, which uses cascades. We design a simple plasmonic device that enables plasmonic-induced absorption (PIA). It consists mainly of two parallel rectangular cavities. The numerical results simulated by using the finite element method (FEM) confirm its function. The corresponding group delay-time can reach –0.146 ps for the PIA window. Based on this result, we propose a cascade device, with the dual-rectangular cavity system as building block, to improve fast-light transmission even more. The results indicate that the cascade scheme can increase the group delay-time to –0.456 ps, which means the fast-light feature is substantially enhanced compared with the non-cascading approach. The effect of the distance between two cascade resonators and other structural parameters is also investigated. Finally, we use this design concept to build a refractive-index sensor with a sensitivity of 701 nm/RIU.

研究了大气衰减、湍流、瞄准误差和空间相关性共同作用的联合效应对大气无线光多输入多输出(MIMO)系统误码率(BER)的影响。利用泊松计数模型和指数相关模型,推导了联合效应下脉冲位置调制(PPM)的最大似然检测准则;采用Wilkinson近似方法推导了大气光MIMO系统BER的上界;仿真分析了联合效应中各因素对大气光MIMO系统BER的影响。结果表明,当大气衰减确定时,空间相关性对系统BER的影响最显著,抖动误差次之,湍流影响最小;当大气衰减变化时,传输距离是影响BER的最重要因素;另外,空间分集对系统性能的改善仅在信道独立时具有较好的效果,信道相关时效果并不明显。

采用全矢量有限元法和分步傅里叶法模拟计算了高非线性光子晶体光纤在近红外光谱区(特别是在850 nm)的飞秒脉冲孤子效应压缩, 提出了一种新的反常群速度色散(β2=-50.698 ps2/km)、小高阶色散和高非线性(γ=268.419 1 W-1/km)二氧化硅芯光子晶体光纤结构, 建立了包含高阶色散和拉曼散射的非线性薛定谔方程, 研究了高斯脉冲在此光纤中传输时, 光纤长度和孤子阶数对脉冲压缩的影响, 分析了光纤中2~5阶色散, 研究表明: 孤子阶数为8时, 品质因子和压缩因子均达到最大, 初始脉冲的峰值功率P0=3 357.8 W, 压缩效果最好; 优化光纤几何和光学参数, 可以得到了高品质因数、小底座的超短光脉冲。

利用矢量光束传输法研究了温度对填充乙醇六边形折射率引导型光子晶体光纤色散、有效面积和非线性的影响。结果表明：温度对色散平坦区域内的色散影响比较大，而且温度越高，色散平坦区间变宽；在平坦区域的短波长范围，温度对色散的影响变化更大，曲线更平坦；温度在长波长比短波长处对光模场面积和非线性系数影响更大；在平坦区域某一波长处，随温度的增加，色散和非线性系数随着升高。研究结果为设计新型光通信和光传感器件提供了理论参考。

优化设计了一种由两种不同大小的空气孔组合而成的双包层六边形空气孔格点光子晶体光纤，并研究了该类光纤的几何参数对色散的影响。结果表明调节包层中空气孔的大小及孔间距,可以容易调节色散及低色散带宽、非线性等性能。优化设计可以得到在C和L波段近零平坦的色散，其色散变化为(0±1.8) ps·km-1·nm-1。

Applicability of the angular properties of scatter elements as a tool to achieve improved slow light performance with small group velocity dispersion and large bandwidth in photonic crystal waveguides is investigated. A polyatomic photonic crystal waveguide, including two scatter elements with different geometrical shapes in each primitive cell, is proposed to investigate the feasibility of our method. Numerical results show that a versatile control of the dispersion relation of slow light modes, with large normalized delay-bandwidth products ranging from 0.2085 to 0.3394, can be obtained using a unique geometrical parameter.