Influence of fused interface on the optical and thermal characteristics of vertical cavity lasers

From the effective absorption coefficient of bonded interface and the relationship of interface to reflectivity at cavity mode for double bonded vertical cavity laser, it can be seen that bonded interfaces should be positioned at the null of standing wave distribution, and the thickness of interface should be less than 20 nm. Using the finite elements method, the temperature contour map of laser can be calculated. Results showed that the influence of thin interface to thermal characteristics of VCSELS is slight, while thick interface will lead to temperature increase of active region. SEM images demonstrate that hydrophobic bonding is suitable for the fabrication of the device, while hydrophilic bonding interface is unfavorable to optical and thermal properties of devices with interface thickness larger than 40 nm.

Extremely low density InAs quantum dots realized in situ on (100) GaAs

Extremely low density self-assembled InAs quantum dots are grown by a combination technique of in situ annealing for 2 min and pause of substrate rotation during molecular beam epitaxy. The surface morphology and structural characteristics of the quantum dots are scrutinized by atomic force microscopy and photoluminescence spectra. It is found that the quantum dot size and density increase as the InAs deposition amount rises. Quantum dots with a density between 2.5 x 10(7) cm(-2) and 2.2 x 10(8) cm(-2) are 2-5 nm in height and 18-39 nm in diameter. It is believed that as-grown InAs nanodots may be of important value for future single quantum dot research.

Design of a fibre-optic disc accelerometer: theory and experiment

Mechanical principles of fibre-optic disc accelerometers (FODA) different from those assumed in previous calculation methods are presented. An FODA with a high sensitivity of 82 rad/ g and a resonance frequency of 360 Hz is designed and tested. In this system, the minimum measurable demodulation phase of the phase-generated carrier (PGC) is 10(-5) rad, and the minimum acceleration reaches 120 ng theoretically. This kind of FODA, with its high responsivity, all-optic-fibre configuration, small size, light weight and stiff shell housing, ensures effective performance in practice.

一种高效的RDF图模式匹配算法

随着越来越多的信息被表示为RDF格式，如何高效地对RDF信息进行分发和过滤成为一个重要的问题．在语义Web环境下的信息分发系统中，输入的RDF信息需要和大量的用户订阅条件进行匹配，而用户的订阅条件可以被表示为RDF图模式．根据RDF图的特点，并对其增加了一些约束．设计了一种新的RDF图模式匹配算法．实验结果表明，该算法的匹配效率远远高于传统的图模式匹配算法．

基于工作流的J2EE遗留系统改造

为了满足用户对软件系统内部业务过程定义的定制需求,针对流行的J2EE平台,以工作流技术为基础设计了对遗留软件系统的改造平台JSPMP。JSPMP利用工作流引擎的过程定义与任务管理能力驱动系统业务流程执行,赋予软件系统在业务过程定义方面的动态可定制性。实践证明,开发者利用此方案能够迅速改造遗留系统,满足用户多样化的过程定制需求,极大地降低了改造、定制成本。

振荡浮子式波浪能转换装置研究

海洋波浪能作为一种无污染的可再生能源，长期以来，世界各国对其投入了大量的研究。振荡水柱（QwC）式波能转换装置由于具有较高的可靠性，在欧洲等一些波能密度较大的国家，得到广泛的采用。但这种装置的缺点在于：建造费用昂贵、施工困难、转换效率低。在波能密度低的国家，如中国，继续采用这种装置就显得很不理想。本文研究的振荡浮子（OD）式波能转换装置用一个放在港中的浮子作为波浪能的吸收载体，然后将浮子吸收的能量通过一个放在岸上的机械或液压装置转换出去，用来驱动电机发电。这种装置的主要优点是：建造成本低、转换效率高。尽管

键合界面对面发射激光器光与热性质的影响

通过界面有效吸收系数的计算及界面对腔模的反射率的影响可知,采用双面键合技术制备面发射激光器应使键合界面处于驻波场分布零点位置,同时界面厚度应该小于20nm以使器件光学性能受界面吸收系数的影响较小.采用有限元方法分析VCSEL温度分布,结果证实薄的键合界面使VCSEL有源区温度对界面的热导率和电导率改变不敏感,而厚的键合界面将可能使有源区温度有较大地升高,给器件带来严重的不良影响.亲水键合和疏水键合的SEM照片说明疏水处理界面较薄,适合用于器件的制备.而亲水处理界面厚度〉40nm,对器件的光、热特性不利.