弧形波导开关阵列的研究

基于非线性克尔效应的自位相调制原理 ,以两模干涉的弧形波导全光开关为单元 ,设计了光强自路由的 1× 4全光交换阵列。经光束传播法数值模拟的结果表明 ,在单路输入的情况下 ,从任一输入端输入的光 ,以其自身的光强为路由信号 ,顺利实现 1× 4的输出切换 ,达到了多路全光自交换的目的     

单纯形法在非线性光波导传播特性分析中的应用

简要介绍了优化理论中的单纯形方法,并且应用到求解介质非线性光波导的色散方程。文中计算了非线性光波导传输特性的2个实例,1）非对称3层平板波导,由线性衬底、克尔型芯区和线性包层（LNL）组成;2）对称3层平板波导,由克尔型包层、衬底及线性芯区组成（NLN）。数值结果表明,非线性光波导的色散方程很困难求解时,单纯形方法对于分析非线性光波导的传输特性简便而且有效。     

饱和线性吸收情况下克尔介质中的激光相移研究

研究强场激光入射时饱和吸收效应对非线性激光相移的影响,由量子光学出发,进行推导,对线性吸收系数进行修正,应用克尔介质的动力学方程,根据薄介质近似,得到非线性相移在介质出射面处的横向分布。     

光开关玻璃的飞秒光学开关特性

通过在碲玻璃中添加重金属离子,尝试制作了具有较大的非线性折射率、时间响应快、吸收小的光开关玻璃。采用超快飞秒光克尔门技术对光开关玻璃的光克尔信号进行测试,测试结果显示,光开关玻璃的光克尔信号对称性好,信号半高宽度达到~225 fs,三阶非线性极化率达到~0.810-20 m2/V2,透过率达到70%~80%;研制的光开关玻璃为皮秒和飞秒光开光材料的选取提供了依据。     

附加类克介质三能级原子系统中光场的相位特性

本文运用 Ｐｅｇｇ－Ｂａｒｎｅｔｔ理论研究类克尔介质腔内相干光场与三能级原子相互作用中相位的演化特性．讨论了类克尔介质的非线性相互作用对相位特性的影响．     

多量子阱光波导中非线性TE波的有限元解

本文提出一种以有限元法为基础的数值方法，用于研究任意非线性介质的多量子阶（ＭＱＷ）光波导中传输与强度有关的ＴＥ波性质．用简单的迭代过程得到自洽解．对于线性或非线性包层区的波导，给出了与功率有关的ＴＥ模的数值结果．结果表明：光的总功率在某一阈值以上时，可以忽略非线性包层区对传播特性的影响．同时，还考查了非克尔型介质与功率有关的行为．     

克尔效应在超短脉冲放大中的影响

从麦克斯韦方程组出发,在考虑了克尔放大介质的增益饱和、增益谱、群速度色散和克尔效应后,建立了描述超短光脉冲在激光放大介质中传输特性的物理模型。运用分步傅里叶变换法,得到了表征克尔效应强弱的B积分及其对光脉冲产生的频率啁啾。最后讨论了克尔效应对光脉冲形状和频谱的影响。     

掺钕光纤放大器非线性折射率的分析

利用描述光纤放大器非线性折射率的公式．通过数值模拟的方法模拟了输入信号功率、抽运功率、信号波长以及增益效应和克尔效应等变量对掺钕光纤放大器非线性折射率的影响，结果表明无论是增加抽运光功率或信号光功率，当信号光的波长小于1064nm时．掺钕光纤放大器的非线性折射率的数值在此波段附近所对应的值为正值，大于此值所对应的值为负值；抽运功率较小时增益效应对非线性折射率的影响较大，而抽运功率较大时克尔效应对非线性折射率的影响较大，这主要是增益饱和所导致的结果；当信号光频率一定时，随抽运功率的增加非线性折射率逐渐增加并达到饱和。     

非线性薄膜中的导模

对于芯区为克尔型非线性介质,衬底和包层为线性介质的LNL型非线性光波导,给出了各层介质中的场分布和功率分布的数学表达式,纠正了Boardman和Egan在1986年发表的文章中的几处差错,给出了正确的色散方程,并对该文中的典型实例进行了计算,给出了数据和曲线,所得结果的正确性已采用了数值分析法进行过核验。     

平板薄膜波导中的非线波导性

光波在非线性介质薄膜波导中的传播特性是当前集成光学领域中的重要研究课题。对它的初步研究展示了微型光学非线性器件的应用前景。本文从平面波理论出发,对呈光学克尔效应的对称型薄膜波导的传输特性进行了分析研究。计算结果表明,这种非线性介质薄膜对TE_0模的传导特性完全不同于线性介质平板波导。非线性介质薄膜的厚度为     

基于非线性放大环镜的全光开关特性研究

采用掺铒光纤放大器(EDFA)和高非线性色散位移光纤(HNL—DSF)组成非线性放大环镜(NALM)，利用掺铒光纤放大器的高增益系数和高非线性色散位移光纤的光学克尔效应构造全光开关，实现脉冲整形和消除干扰噪声。采用分布傅里叶法分析了高非线性色散位移光纤的群速度色散(GVD)对非线性放大环镜开关特性的影响，讨论了掺铒光纤放大器的增益系数、增益饱和特性以及耦合器的耦合比等因素的影响，研究了入射光为高斯脉冲的情况下，非线性放大环镜与入射光信号强度相关的放大滤波特性。通过优化非线性放大环镜的各项参数，可以在实现高开关效率的同时，降低对开关功率的要求，对峰值功率低于1mW的超短脉冲进行Tbit／s量级的开关操作，从而适用于超高速大容量光通信系统中。     

Nonlinear Sagnac interferometer switch and its applications

Ultrafast all-optical switching based on the optical Kerr effect in a Sagnac interferometer which consists of a dichroic polarization-maintaining fiber coupler and dispersion-shifted polarization-maintaining fiber loop is reported. This nonlinear Sagnac interferometer switch has the advantage of high stability originating from completely balanced interfering arms. In addition, because dispersion-shifted fibers were used, increases in switching power and switching time were prevented. Moreover, polarization fluctuation was completely suppressed due to the all-polarization maintaining fiber configuration. The required switching power for complete switching was measured to be 1.8 W for a 200-m-long fiber. All-optical time division demultiplexing and logic operations, including inversion and operation, using the nonlinear Sagnac interferometer switch were successfully demonstrated at 5 Gb/s     

基于克尔晶体的FROG光学任意波形测量技术

利用光克尔效应和交叉相位调制效应,采用基于矩阵的主元素广义投影(PCGP)算法,提出了基于克尔晶体的频率分辨光学开关法(FROG)光学任意波形测量方案.建立了基于克尔晶体的FROG光学任意波形测量的理论模型,并对该方案进行了仿真研究,讨论背景噪声处理、门函数形状、门波形幅度对波形恢复的影响.仿真结果表明:该方案可以实现对光学任意波形的幅度和相位的准确测量;门脉冲采用矩形波形时,光学任意波形的测量准确性较高.     

Numerical Study of Few-Cycle Pulses by Nonlinear Compression in Two-Photon Semiconductor Amplifiers

Optical pulse compression down to a few optical cycles by the ultrabroadband gain of nonlinear two-photon process in semiconductors is proposed. Recent experimental demonstration of semiconductor two-photon gain (TPG) has motivated this analysis of ultrashort pulse dynamics with realistic semiconductor parameters. Comprehensive material model, including TPG, carrier depletion, linear absorption, Kerr effect, plasma response of injected carriers, and the material dispersion were numerically simulated using the finite-difference time-domain method. Pulse compression down to a few optical cycles is theoretically predicted.      

基于半导体放大器实现多功能超宽带调制的研究

基于半导体放大器(SOA)的增益饱和效应,提出了一种简单的实现多功能超宽带(UWB)调制的方案。方案采用一个光源和单个SOA,可以实现脉冲波形调制(PSM)、脉冲幅度调制(PAM)和脉冲极性调制(BPM),因此实现容易、结构简单和成本低。利用OptiSystem软件对方案进行了仿真研究,分析了各参数对调制信号的影响以及信号的传输特性。结果表明,本方案对光源的波长和光源的光功率的变化不敏感,仿真输出的调制信号在单模光纤(SMF)中可传输35km。     

Dynamic Switching Response of Semiconductor Ring Lasers to NRZ and RZ Injection Signals

Dynamic response of semiconductor ring lasers (SRLs) to external optical injection with nonreturn-to-zero (NRZ) and return-to-zero (RZ) waveforms is investigated using a model including linear and nonlinear mode coupling. The switching characteristics are simulated under various device sizes, injection power levels, and frequency detuning. For NRZ, the switching time reduces with decreasing SRL radius, which has a reasonable agreement with the current experimental results. It is also demonstrated that RZ pulse with duration of several picoseconds can reliably switch 6-mum radius SRL over a detuning range of more than 100 GHz, with the end state self-sustained after switching.     

二维光子晶体耦合腔的多模双稳态光开关

利用时域有限差分数值模拟方法和耦合模理论分析方法，研究了Kerr型非线性二维光子晶体耦合腔结构中的光学双稳态开关。利用耦合模理论，分析了耦合腔结构的多模特性，以及对应本征态的局域强度分布特性，并讨论了在耦合腔结构中实现多模光学双稳态开关的原理。发现在二维耦合腔结构中，可以实现信号自泵浦和泵浦-信号两种类型的双稳态开关，且后者具有使泵浦和信号在频率和空间相分离的优点。利用非线性时域有限差分数值模拟方法，得到了高斯脉冲激励下的双稳态响应曲线。     

Optical bistability and all-optical switching in novel waveguidejunctions with localized optical nonlinearity

We propose novel all-optical guided-wave devices using the structure with localized third-order optical nonlinearity where only a selected part of a waveguide both in a cross section and along a propagation direction is made from a Kerr-like nonlinear material and the rest are made from linear ones. Optical bistable devices and all-optical switching devices are realizable by utilizing bistable like nonlinear dispersion characteristics in selectively nonlinear guided-wave systems. Optical bistability and all-optical switching characteristics are analyzed in waveguide Y-junctions adopted the scheme by using a modified BPM combined with the normal mode analysis. The method to realize the guided-wave structure with localized nonlinearity is also discussed     

Proposal of all-optical wavelength-selective switching using waveguide-type Raman amplifiers and 3-dB couplers

We propose a new optical switch that can enable wavelength-selective high-speed switching for applications to photonic wavelength-division multiplexing (WDM) Internet protocol (IP) packet routing. The switch utilizes characteristics of waveguide-type Raman amplifiers and 3-dB couplers, and so it operates all-optically at a few tens of picosecond or faster speed. The operation of the switch is studied by coupled-mode theory and is verified numerically using a beam-propagation method (BPM). As a result, we found that optical waves having arbitrary wavelengths among those of incident WDM waves are amplified and switched when the amplification rate of each waveguide-type Raman amplifier is set to the proper value by pump wave injection. Moreover, the dynamic range over 30 dB was also obtained from the simulation results of the switch.