slot波导包覆层对功率密度的影响

理论模拟研究了硅基绝缘(SOI)的slot波导中槽内限制功率与slot波导的结构参数以及包覆层折射率的关系.结果表明,如果包覆层的折射率偏离衬底SiO2的折射率,相同参数下的slot波导的传输损耗大于包覆层为SiO2的结构的传输损耗.分析表明,如果包层与衬底折射率不同,限制的光功率会从slot缝隙中渗透到折射率较高的衬底或者包层中,从而引起能量的损耗.理论模拟得到了在缝隙宽度为0.12μm的情况下,slot波导槽内最大的光功率限制为28.54%,这个值包含了纳米线波导与slot波导直接耦合产生的耦合损耗以及slot波导自身的传输损耗.     

K~ 交换玻璃条形光波导

为了在玻璃衬底上产生波导层,必须设法使这一层的折射率n大于周围介质的折射率。玻璃的折射率与玻璃的密度和构成玻璃的各种离子的电极化率有关,如果将重离子如Ag~ 、K~ 、Tl~ 等扩散到玻璃中去取代较轻的离子Na~ 和Li~ ,在交换区的折射率就会高于非交换区,从而形成波导。 溶盐一般采用AgNO_3、TINO_3、KNO_3等,前二种波导国内已有人研究过,这里报告的是把抛光的K_7玻璃浸在KNO_3溶液中,在380℃恒温1～20小时制成的单模光波导。     

观察波导模式及测量薄膜参数用的对称棱镜光波耦合器

棱镜光波耦合器是向波导薄膜馈送和取出光能、选择激发波导模式、精确测量薄膜参数的重要器件。 图1为直角和对称棱镜光波耦合器的略图。n_0、n_1、n_2、n_3分别表示衬底、薄膜、空气和棱镜的折射率,S为空气隙宽度。根据全反射和相干加强条件以及Snell定律,可导出波导模式特征方程及有效折射率为:     

锗薄膜在低温下的折射率研究（英文）

利用电子束蒸发方法在双面抛光的ZnSe基底上镀制单层Ge薄膜.在80 K~300 K温度范围内,采用PerkinElmer Frontier傅里叶变换红外光谱仪低温测试系统每20 K测量Ge单层在2~15μm波长范围的透射率.采用全光谱反演拟合方法得到Ge单层在不同温度下的折射率.结果显示,Ge单层折射率均随波长增大而减小,且变化趋势基本相同.利用Cauchy色散公式对折射率波长色散关系进行拟合,得到Ge薄膜材料折射率温度/波长色散表达式为:n(λ,T)=3.29669+0.00015T+5.96834×10~(-6)T~2+0.416 98/λ~2+0.173 84/λ~4.最后,验证了Ge单层膜折射率温度/波长色散公式的准确性.     

缓冲质子源LiNbO3波导折射率计算及实验

为实现铌酸锂退火质子交换(APE)波导折射率分布的准确计算,选择含苯甲酸锂的苯甲酸缓冲液作为质子交换质子源,高温退火制作了波导样本.针对该工艺过程建立退火质子交换波导模型,包括非线性扩散模块和光学数值仿真模块,分别计算APE波导折射率及其模式有效折射率.以测得的样本波导模式有效折射率和计算的有效折射率差的均方根构建评价函数(FOM),结合遗传算法提取该工艺条件下质子扩散参数,实现了不同交换深度和退火时间波导折射率分布及其光学特性的一体化计算.实验表明:FOM小于0.001,计算折射率分布同IWKB方法测得结果吻合较好,最大偏差约0.002.     

质子交换LiNbO3波导的特性研究

本文研究了采用质子交换与退火工艺相结合所制作的LiNbn_3波导的特性。用WKB法测量了折射率分布剖面,并提出一种新的两棱镜法测量了波导损耗。结果表明:质子交换与退火工艺相结合,可使LiNbo_3波导的表面折射率降低0.0363,波导层向衬底内扩展,折射率剖面变为渐变形,同时损耗降低到0.4dB。     

质子交换MgO：Linbo_3波导及其镁含量对波导性能影响的研究

报道了不同镁含量质子交换ＭｇＯ：ＬｉＮｂＯ３波导的制备与表征。采用多个测量波长，测量并计算了不同镁含量的Ｚ切质子交换ＭｇＯ：ＬｉＮｂＯ３波导的阶跃式折射率分布，结果表明多波长测量结果一致。给出了波导层折射率增量的波长色散，发现了波导层折射率增量和同一温度下波导的扩散系数随晶体中镁含量的增加而减小，最后讨论了镁含量对波导性能影响的机制。     

硅基SiO_2光波导

在硅基上通过氢氧焰淀积的 Si O2 ,厚度达到了 2 0 μm;通过掺 Ge增加芯层的折射率 ,折射率比小于 1% ,并可调 ;用反应离子刻蚀工艺对波导的芯层进行刻蚀 ,刻蚀深度为 6 μm,刻蚀深宽比大于 10 ;波导传输损耗小于0 .6 d B/ cm(λ=1.5 5 μm) ,并对波导的损耗机理和测试进行了分析与研究 .另外 ,为实现光纤与波导的耦合 ,结合微电子机械系统技术 ,在波导基片上制作了光纤对准 V形槽     

把LiNbO3浸入苯甲酸-苯甲酸锂混合融体中制备质子交换波导

把X-或Y-切割的LiNbO3晶体放入苹甲酸-苯甲酸锂（0．5～2Mol%）混合体中，于218—248℃的温度范围内制备了质子交换波导。质子变换过程的扩散常数与混合体中苯甲酸锂含量有关。从反W.K.B法算出的折射率剖面表面，不管锂含量多少、交换时间长短以及交换时的温度高低，质子交换层是折射率突变层，其表面折射率均相同。这里也给出了退火后样品的折射率剖面以及对退火样品作第二次质子交换后的折射率剖面．     

Ti:LiNbO_3质子交换光波导

本文研究了在Ti扩散LiNbO_3衬底上用苯甲酸质子交换制备光波导的方法,以及单模条件、折射率分布、交换系数、表面状态和热稳定性等问题。     

Definition of function of squares amount of angular part of film element

By means of exact conformal mapping method we have defined character of dependence of squares amounts of angular part of film element on angled part dimension. We propose relations, approximating obtained dependence. Calculation results and experimental researches of large-scale models are represented.     

Temperature dependence of index of refraction of polymericwaveguides

The temperature dependence of refractive index of polymer films was determined for a number of slab waveguides by a grating coupling method. This dependence was examined as a function of parameters such as molecular weight and glass transition temperature of the polymer. Temperature-induced changes in N_TE-N_TM , N being the effective index, were studied systematically for different slab waveguide compositions. It is shown that with proper device design and choice of polymeric materials, thermal effects can be reduced     

Interpretation of responses of visual cells of limulus

Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature.     

Application of model of mixture of probabilistic distributions for definition of the signals of radiophysical probing

The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde.     

近红外光谱技术在水果品质无损检测中应用的研究与现状

简单概述了我国水果产业的发展现状,着重阐述了国内外利用近红外光谱技术进行水果品质无损检测的最新研究进展,分析了当今研究中存在的问题,并对利用近红外光谱技术进行水果检测的前景进行了展望,提出了一些建议。     

星载差分吸收光谱仪转动部件测试系统设计

基于星载差分吸收光谱仪转动部件控制需求,设计了星载光谱仪转动部件的测试系统。采用微动开关复位加定步的电机运动方式实现电机的精确定位。采用脉冲调制（PWM）的方式实现驱动电流的精细调节。并搭建平台对系统进行重复性测试,实验结果表明,测试系统具有较高的可靠性和稳定性,能够满足光谱仪的精确定位要求,使电机在工作寿命内按计划完成定标工作。     

Computer simulation of the processes of formation of microclusters on the basis of scaling invariance of random walk

On the basis of scaling invariance of the process of random walk, a discrete three-dimensional algorithm is developed and implemented for computer simulation of the multistage processes of formation of porous clusters in a crystal matrix. A software package is worked out that provides the simulation of dynamic processes of clustering deep in the crystals with allowance for surface processes, applied external fields, and chemical reactions accompanying the processes of clustering. The morphological pattern of pores formed by the simulation is correlated with the behavior of the current-voltage characteristic of anodizing.     

Tail of the distribution of sums of log-normal variates

It is shown that the asymptotic behavior of the tail of the sum distribution of a finite number of individually log-normal distributed variates displays the log-normal character of those variates with maximum logarithmic variance. A quantitative definition of the sum-distribution "tail" is established in terms of upper bounds on the relative error or deviation from the asymptotic log-normal property.     

Terminology of carcinogenesis in light of the current concepts of the mechanisms of action of chemical carcinogens

The approaches to prepare a uniform and unified scientific terminology of chemical carcinogenesis are presented. The main definitions proposed (carcinogen, initiation, promotion, mutagen, multistage carcinogenesis, anti-carcinogen, cocarcinogen, carcinogenic risk, etc.) are based on the current state of comprehending mechanisms of the action of chemical carcinogens.     

基于数字电视整体平移的遥控器的选择之我见

从红外遥控器的分类出发,介绍了“固定编码＋学习型”遥控器的结构、部件的选择,以及功能按键的选择、排列,然后从其技术规格及技术测试方面介绍了其选择的一些重点项目,最后,就弥补学习型遥控器的网络遥控器的应用作了简单分析。