32 Gb/s multilevel modulation of an 850 nm VCSEL for next-generation datacommunication standards

An 850 nm vertical-cavity surface-emitting laser is modulated at 32 Gb/s using pulseamplitude modulation with four levels. Transmitter predistortion generates an optimized modulation waveform, which requires a receiver bandwidth of only 15 GHz. © OSA/ CLEO 2011.

The fabrication and properties of InAs/GaAs columnal islands

A columnal islands system, which was composed of three layers of self-assembled InAs/GaAs quantum dots (QDs), has been fabricated by solid-source molecular beam epitaxy (MBE) through S-K mode on a (100) semi-insulating GaAs substrate. The effects of the thickness of GaAs space layer, the growth interruption time and the amount of InAs deposition on the emission wavelength of columnal islands were presented. The image of atomic force microscopy (AFM) indicated the columnal islands with high uniformity in size and shape. At room temperature, the emission wavelength of columnal islands with different effective heights was achieved 1.32 and 1.4 mum; however, the emission wavelength of single-layer QDs with normal height was just 1. l mum. It provides a useful and intuitive approach to artificially control the emission wavelength of a QD material system.

Narrow-channel-spacing 32-channel arrayed-waveguide-grating multiplexer with an innovative alignment method

A 32-channel 50-GHz spaced arrayed-waveguide grating with our innovative configuration has been designed and fabricated. The performance of the device has been fully tested by using a tunable laser light source, optical power meter, and polarization controller. The insertion loss (IS) of the device is 4.2 similar to 7.4 dB. The crosstalk is about -28 clB. The IS uniformity is less than 3.2 dB. With our configuration, the performance of the device has been enhanced effectively and the difficulty in alignment process has been decreased obviously. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

顶部平坦化32通道AWG的设计与研制

根据优化输入端多模干涉器（MMI）结构设计，研制出32通道50GHz通道间隔、顶部平坦化的阵列波导光栅（AWG）器件。该器件的采用6μm×6μm折射率差为0．75％的Si基SiO2埋型波导结构，阵列波导数为130，罗兰圆半径为9419．72μm，相邻阵列波导长度差为128．42μm。测试结果表明

InAs/GaAs柱形岛的制备及特性研究

利用固源分子束外延(MBE)的方法经SK模式自组装生长由多层InAs/GaAs量子点组成的柱形岛.具体分析了GaAs间隔层厚度,生长停顿时间以及InAs淀积量对发光峰波长的影响.原子力显微镜(AFM)结果显示柱形岛表面的形状和尺寸都比较均匀;室温下不同高度的柱形岛样品的发光波长分别达到1.32和1.4μm,而单层量子点的发光波长仅为1.1μm,充分说明了量子点高度对发光波长的决定性影响,这为调节量子点发光波长提供了一种直观且行之有效的方法.

长安四府村32～10kaBP期间沙尘暴活动的记录

IEECAS SKLLQG

由剂量当量率估算52MeV/u~(32)S+Ta的中子与γ光子产额

研究通过测量中子和γ剂量当量率估算 5 2MeV/u32 S束轰击Ta靶时的中子与γ光子产额的方法 ,并给出了估算结果。

白浆土－植物系统营养物质转化机制及其有效性研究Ⅰ．~（32）P同位素示踪法对白浆土中P肥利用率

利用３２Ｐ同位素示踪法对白浆土中Ｐ肥利用率进行了研究．结果表明，在岗地白浆土上，表层土壤表现出一定程度的供Ｐ不足现象，白浆层土壤有效Ｐ含量严重缺乏．表层土壤中当季Ｐ肥利用率的变幅范围为６．０９～１２．３５％，白浆层土壤Ｐ肥利用率为１３％左右．施用有机肥能明显提高白浆土ＯｌｓｅｎＰ的含量，加速土壤本身Ｐ的活化，各种有机物中，以猪粪对土壤潜在Ｐ的活化效果最好．将ＯｌｓｅｎＰ与Ｘ值、Ａ值比较，认为ＯｌｓｅｎＰ是评价白浆上Ｐ肥力简便易行的可靠指标．

A {Co-32} Nanosphere Supported by p-tert-Butylthiacalix[4]arene

Calixarene-capped Co-32 clusters are constructed by a sodalite Co-24(II) cage and an encapsulated Co-8(III) cube. The spherical units are arranged into three isomeric structures, two of which are stacked by the bcc lattices and the third of which is assembled by the cubic closest packing of the spherical units.