1.55-μm大功率高速直调半导体激光器阵列

提出一种基于AlGaInAs材料的1.55-μm波段的大功率、高速直调分布反馈(DFB)激光器阵列。采用具有良好温度特性和高微分增益的AlGaInAs材料作为量子阱和波导层以实现大功率与高带宽的输出;引入稀释波导结构来减小有源区内部损耗,同时降低远场发散角;采用悬浮光栅并优化耦合系数以实现大注入电流下的单模稳定工作。最终实现了1.5-μm波段5波长的大功率直调激光器阵列,阵列波长间隔约为5 nm,室温连续波(CW)工作时各通道输出光功率均大于100 mW,单通道最大输出光功率为160 mW,500 mA工作电流范围内边模抑制比大于55 dB,小信号调制带宽可达7 GHz,激光器最小线宽为520 kHz,相对强度噪声低于-145 dB/Hz。     

Dependence of bimodal size distribution on temperature and optical properties of InAs quantum dots grown on vicinal GaAs （100） substrates by using MOCVD

Self-assembled InAs quantum dots (QDs) are grown on vicinal GaAs (100) substrates by using metal-organic chemical vapour deposition (MOCVD). An abnormal temperature dependence of bimodal size distribution of InAs quantum dots is found. As the temperature increases, the density of the small dots grows larger while the density of the large dots turns smaller, which is contrary to the evolution of QDs on exact GaAs (100) substrates. This trend is explained by taking into account the presence of multiatomic steps on the substrates. The optical properties of InAs QDs on vicinal GaAs(100) substrates are also studied by photoluminescence (PL) . It is found that dots on a vicinal substrate have a longer emission wavelength, a narrower PL line width and a much larger PL intensity.     

A 10 Gb/s 1.5 μm Widely Tunable Directly Modulated InGaAsP/InP DBR Laser

We report 10 Gb/s data transmissions using a packaged two-section InGaAsP/InP distributed Bragg reflector(DBR) laser. The tunable DBR laser has a wavelength tuning range of 12.12 nm. The DBR laser has greater than 10.84 GHz 3-dB direct modulation bandwidth within the wavelength tuning range. The 10 Gb/s data transmissions are performed at up to a distance of 30-km.     

Dual-Wavelength Distributed Feedback Laser for CWDM Based on Non-Identical Quantum Well

Using non-identical quantum wells as the active material, a new distributed-feedback laser is fabricated with period varied Bragg grating. The full width at half maximum of I 15 nm is observed in the amplified spontaneous emission spectrum of this material, which is flatter and wider than that of the identical quantum wells. Two wavelengths of 1.51 μm and 1.53 μm are realized under different work conditions. The side-mode suppression ratios of both wavelengths reach 40 dB. This device can be used as the light source of coarse wavelength division multiplexer communication systems.     

两部门的时滞经济增长模型

本文考虑了存在生产滞后的 Furuno两部门经济增长模型 .给出了此模型资本 -劳动比 k的稳定性和振荡性 ,分析了生产周期时滞对 k稳定性区域的影响 .进一步利用 Hopf分支的方法讨论了 Furuno模型存在周期轨道的条件 .     

非自治Lotkz—Volterra扩散模型的持续生存与周期轨道

本文研究了一类非自治的捕食者的一食饵扩散模型；其中食饵能在环境相异的两个缀块间有限制地扩散，但对捕食者来说，缀块间扩散不受任何限制；     

Novel electroabsorption modulator monolithically integrated with spot-size converter

A novel 1.55-μm spot-size converter integrated electroabsorption modulator was designed with conventional photolithography and chemical wet etching process. A ridge double-core structure was employed for the modulator, and a buried ridge double-core structure was incorporated for the spot-size converter. The passive waveguide was optically combined with a laterally tapered active waveguide to control the mode size. The figure of merit is 4.1667 dB/V(/100 μm) and the beam divergence angles in the horizontal and vertical directions were as small as 11.2°and 13.0°, respectively.     

Growth of High-Quality GaAs on Ge by Controlling the Thickness and Growth Temperature of Buffer Layer

In the last two decades, m-v compound semi- conductor materials grown on elemental semiconduc- tor substrates have attracted much attention due to their potential applications in high-efficiency so- lar cells, photodetectors, quantum-dot （QD） lasers, and metal-oxide-semiconductor field-effect transistors （MOSFETs）. Due to their extremely high electron mobility, III-V semiconductors such as GaAs, InGaAs and InAs are believed to be chan- nel materials for future complementary metal-oxide- semiconductor （CMOS） technology.CMOS tran- sistors on Ge substrates with high mobility In- GaAs/Ge channels have already been fabricated by using a wafer bonding technique, which is a promis- ing step for such a device on Si.     

Integrated electroabsorption-modulated DFB laser by using an improved butt-joint method

An improved butt coupling method is used to fabricate an electroabsorption modulator (EAM) monolithically integrated with a distributed feedback (DFB) laser. The obtained electroabsorption-modulated laser (EML) chip with the traditional shallow ridge exhibits very low threshold current of 12 mA, output power of more than 8 mW, and static extinction ratio of -7 dB at the applied bias voltage from 0.5 to -2.0 V.