A pair of integrated optoelectronic transceiving chips for optical interconnects

In this Letter, a pair of integrated optoelectronic transceiving chips is proposed. They are constructed by integrating a vertical cavity surface emitting laser unit above a positive-intrinsic-negative photodetector unit. One of the transceiving chips emits light at the wavelength of 848.1 nm with a threshold current of 0.8 mA and a slope efficiency of 0.81 W/A. It receives light between 801 and 814 nm with a quantum efficiency of higher than 70%.On its counterpart, the other one of the transceiving chips emits light at the wavelength of 805.3 nm with a threshold current of 1.1 mA and a slope efficiency of 0.86 W/A. It receives light between 838 and 855 nm with a quantum efficiency of higher than 70%. The proposed pair of integrated optoelectronic transceiving chips can work full-duplex with each other, and they can be applied to single fiber bidirectional optical interconnects.     

Integrated optoelectronic chip pair for transmitting and receiving optical signals simultaneously

An integrated optoelectronic chip pair, which can transmit and receive optical signals simultaneously, is proposed in this Letter. The design and optimization of its key structure, the vertical cavity surface emitting laser's distributed Bragg reflector, are presented. Analysis is also done for its influence on the integrated chip's performance. Moreover, the chip pair's performance under dynamic conditions is analyzed. Their 3 dB modulation bandwidths are higher than 10 GHz, and their 3 dB photo-response bandwidths are around 23 GHz. Their applications will further improve the performances of the optical interconnects.     

Stacking-faults-free zinc blende GaAs/AlGaAs axial heterostructure nanowires during vapor-liquid-solid growth

Pure zinc blende structure GaAs/AlGaAs axial heterostructure nanowires (NWs) are grown by metal organic chemical vapor deposition on GaAs(111) B substrates using Au-catalyzed vapor-liquid-solid mechanism.Al adatom enhances the influence of diameters on NWs growth rate.NWs are grown mainly through the contributions from the direct impingement of the precursors onto the alloy droplets and not so much from adatom diffusion.The results indicate that the droplet acts as a catalyst rather than an adatom collector.     

光通信链路中集成芯片的收发一体工作

在PIN光电探测器(PIN-PD)结构的垂直方向上集成垂直腔面发射激光器(VCSEL)结构单元,实现了收发一体式工作的集成光电芯片对,可用于进一步提高光互连的性能。该集成光电芯片可以同时对两个波段进行收发一体工作,一端进行中心波长为805 nm的光信号的发送和中心波长为850 nm的光信号的接收,另一端进行中心波长为850 nm的光信号的发送和中心波长为805 nm的光信号接收。仿真优化805 nm波长处光信号发送端的结构与性能,理论分析结构中VCSEL单元和PIN-PD单元工作时的电学隔离和光学解耦,最终证实本结构可以同时进行收发一体的工作。     

Influence of GaAs substrate on the transmission performance of epitaxially grown Fabry-P'erot filter

The influence of GaAs substrate on the transmission performance of a multi-film Fabry-P’erot filter (FPF),fabricated by metalorganic chemical vapor deposition epitaxial growth on GaAs substrate,is investigated using the transfer matrix method.On the basis of the theoretical simulation,we determine that the quality of the resonant transmission peak of this epitaxially grown FPF (EG-FPF) deteriorates through splitting when the substrate is taken into account.Rapid periodic oscillation of peak-transmittivity along with the alteration of substrate thickness is also observed in the simulation results.Finally,a remarkably improved transmission performance of the EG-FPF is obtained by thinning the substrate down to a suitable thickness range through well-controlled grinding and polishing.     

MOCVD反应器热流场的数值模拟研究

本文以低压、旋转、垂直喷淋结构的MOCVD反应器为对象,应用二维数学模型分析与计算,对反应器内部的质量输运过程进行了比较详细的研究与讨论.通过计算发现:在一定范围内,增加进气流量Q、降低操作压力P、设定适宜的生长温度t、保持合理的基座转速ω等,不仅可以非常有效地抑制热浮力效应,同时也使衬底表面流体的流动速度进一步增加,从而实现反应器内部的流场和温度场的均匀分布.研究的结果,不仅为高品质的外延生长提供了有效的解决方案,而且也为MOCVD反应器的优化设计提供了重要的参考依据.     

一种设计环形汇聚光栅反射镜的新方法

提出了一种利用数学变换来快速设计环形汇聚光栅反射镜的方法.通过分析具体的物理场景,抽象出已有条形汇聚光栅的"线"汇聚特性与所要设计的"点"汇聚特性在数学上对应的变换关系,然后用该数学变换对条形汇聚光栅进行外形上的变换,外形变换后的条形光栅即为可以实现"点"汇聚的环形光栅.用有限元算法对设计的环形汇聚光栅进行仿真,仿真证明采用该方法设计的环形光栅可以很好地实现高反、高汇聚.采用这一方法,设计了直径为29.788μm的环形光栅反射镜,当垂直入射的径向偏振光从设计的环形光栅表面反射回来后将发生汇聚,汇聚焦点位于环形光栅表面10μm处.经计算,反射镜的数值孔径为0.8302,反射率为0.9163,在焦点所在的汇聚面上,汇聚光栅电场分布的半高宽为1.5548μm.