基于DFB激光器的光学微波信号的产生

采用量子阱混杂的材料集成技术制备并联分布反馈激光器和Y形波导耦合器集成的新型光电器件.两个并联分布反馈激光器的激射模式在频率上稍有差别,这两束不同频率的激光在Y形波导耦合器拍频产生光学微波信号.分别独立调节注入到两个激光器的电流大小,可以得到从13 GHz到42 GHz连续可调的光学微波信号. 关键词： 光学微波信号生成 分布反馈激光器 Y形波导 拍频     

Analysis on high speed response of a uni-traveling-carrier double hetero-junction phototransistor

In this paper, the positive influence of a uni-traveling-carrier(UTC) structure to ease the contract between the responsivity and working speed of the In P-based double hetero-junction phototransistor(DHPT) is illustrated in detail. Different results under electrical bias, optical bias or combined electrical and optical bias are analyzed for an excellent UTC-DHPT performance. The results show that when the UTC-DHPT operates at three-terminal(3T) working mode with combined electrical bias and optical bias in base, it keeps a high optical responsivity of 34.72 A/W and the highest optical transition frequency of 120 GHz. The current gain of the 3T UTC-DHPT under 1.55-μm light illuminations reaches 62 d B. This indicates that the combined base electrical bias and optical bias of 3T UTC-DHPT can make sure that the UTC-DHPT provides high optical current gain and high optical transition frequency simultaneously.     

Optical microwave generation using two parallel DFB lasers integrated with Y-branch waveguide coupler

A new device of two parallel distributed feedback (DFB) lasers integrated monolithically with Y-branch waveguide coupler was fabricated by means of quantum well intermixing. Optical microwave signal was generated in the Y-branch waveguide coupler through frequency beating of the two laser modes coming from two DFB laser in parallel, which had a small difference in frequency. Continuous rapid tuning of optical microwave signal from 13 to 42GHz were realized by adjusting independently the driving currents injected into the two DFB lasers.     

Effect of lateral structure parameters of SiGe HBTs on synthesized active inductors

The effect of lateral structure parameters of transistors including emitter width, emitter length, and emitter stripe number on the performance parameters of the active inductor(AI), such as the effective inductance Ls, quality factor Q,and self-resonant frequency ω_0 is analyzed based on 0.35-μm Si Ge Bi CMOS process. The simulation results show that for AI operated under fixed current density JC, the HBT lateral structure parameters have significant effect on Ls but little influence on Q and ω_0, and the larger Ls can be realized by the narrow, short emitter stripe and few emitter stripes of Si Ge HBTs. On the other hand, for AI with fixed HBT size, smaller JCis beneficial for AI to obtain larger Ls, but with a cost of smaller Q and ω_0. In addition, under the fixed collector current IC, the larger the size of HBT is, the larger Ls becomes, but the smaller Q and ω_0 become. The obtained results provide a reference for selecting geometry of transistors and operational condition in the design of active inductors.