Modeling analysis and optimization design of the thermostatical control system of laser instrument of the semiconductor

Influence produced by the heat effect at work of the laser instrument crystal of the semiconductor, the text designs a kind of temperature control system to the crystal of the laser instrument, using the thought and method of the classical control theory to analyze this temperature control system, and establishes mathematics model. According to mathematics model the text demonstrated the system at S field and time- area, and proposed optimizing basis to the total mark of proportion and differential parameter to con- troller PID, thus proposed a kind of temperature control scheme. And the thermostatically system is simulated by MATLAB.

Multifunctional silicon-based light emitting device in standard complementary metal oxide semiconductor technology

A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology. This device is capable of versatile working modes： it can emit visible to near infra-red （NIR） light （the spectrum ranges from 500 nm to 1000 nm） in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light （the spectrum ranges from 900 nm to 1300 nm） in the forward injection mode with working voltage below 2 V. An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode. Furthermore, when the gate oxide is broken down, NIR light is emitted from the polysilicon/oxide/silicon structure. Optoelectronic characteristics of the device working in different modes are measured and compared. The mechanisms behind these different emissions are explored.

A contrivance of 277 nm DUV LD with B0.313Ga0.687N/B0.40Ga0.60N QWs and AlxGa1–xN heterojunction grown on AlN substrate

In this paper,an ultraviolet C-band laser diode lasing at 277 nm composed of B0.313Ga0.687N/B0.40Ga0.60N QW/QB heterostructure on Mg and Si-doped AlxGa1-xN layers was designed,as well as a lowest reported substitutional accepter and donor concentration up to NA=5.0×10^17 cm^-3 and ND=9.0×10^16 cm^-3 for deep ultraviolet lasing was achieved.The structure was assumed to be grown over bulk AIN substrate and operate under a continuous wave at room temperature.Although there is an emphasizing of the suitability for using boron nitride wide band gap in the deep ultraviolet region,there is still a shortage of investigation about the ternary BGaN in aluminum-rich AIGaN alloys.Based on the simulation,an average local gain in quantum wells of 1946 cm^-1,the maximum emitted power of 2.4 W,the threshold current of 500 mA,a slope efficiency of 1.91 W/A as well as an average DC resistance for the V-I curve of(0.336Ω)had been observed.Along with an investigation regarding different EBL,designs were included with tapered and inverse tapered structure.Therefore,it had been found a good agreement with the published results for tapered EBL design,with an overweighting for a proposed inverse tapered EBL design.

大功率GRIN-SCH-SQW激光器阵列

分析了梯度折射率分别限制单量子阱 (GRIN-SCH-SQW)结构的特点以及对大功率半导体激光器特性的影响。利用分子束外延系统生长 Ga Al As/Ga As GRIN-SCH-SQW结构 ,经光荧光谱、X-射线双晶衍射、和载流子浓度测试 ,结果表明 ,该结构各参数均满足设计要求。应用此结构制成激光器阵列 ,室温准连续输出功率达5 8W(t=2 0 0 μs,f=5 0 Hz) ,峰值波长为 80 8nm。

镓铟砷/铝铟砷QW LD中俄歇复合及其对T_0的影响

修正了现行俄歇复合率的公式，并用之分析了晶格匹配ＧａＩｎＡｓ／ＡｌＩｎＡｓ异质材料系统在有无量子尺寸效应情况下的俄歇复合率随载流子浓度和温度变化的行为。发现其阈值电流密度随温度的变化行为可分为特征温度（Ｔ０）不同的相邻两个温区，在较高温区，量子尺寸效应作用不大，在较低温区，量子尺寸效应反而降低了Ｔ０，并对此意外的现象提出初步的解释。

Progress in Antimonide Based III-V Compound Semiconductors and Devices

In recent years, the narrow bandgap antimonide based compound semiconductors (ABCS) are widely regarded as the first candidate materials for fabrication of the third generation infrared photon detectors and integrated circuits with ultra-high speed and ultra-low power consumption. Due to their unique bandgap structure and physical properties, it makes a vast space to develop various novel devices, and becomes a hot research area in many developed countries such as USA, Japan, Germany and Israel etc. Research progress in the preparation and application of ABCS materials, existing problems and some latest results are briefly introduced.

Multi-wavelength fiber ring laser based on semiconductor optical amplifier and sampled fiber Bragg grating in a Sagnac loop interferometer

Multi-wavelength fiber ring laser based on the semiconductor optical amplifier(SOA)with sampled fiber Bragg grating(SFBG)in a Sagnac loop interferometer as the wavelength-selective filter is proposed.Four lasing wavelengths with 1.8 nm spacing have been generated stably at room temperature.The proposed laser has the advan-tages such as removal of the high-cost circulator,flexibility in channel-spacing tuning,and simple all-optical fiber configuration,which has potential applications in high-capacity wavelength-division-multiplexed(WDM)systems and mechanical sensors.

40-GHz wavelength tunable mode-locked SOA-based fiber laser with 40-nm tuning range

A 40-GHz wavelength tunable mode-locked fiber ring laser based on cross-gain modulation in a semicon- ductor optical amplifier （SOA） is presented. Pulse trains with a pulse width of 10.5 ps at 40-GHz repetition frequency are obtained. The laser operates with almost 40-nm tuning range. The relationship between the key laser parameters and the output pulse characteristics is analyzed experimentally.

Design of a single-mode directly modulated orbital angular momentum laser

We propose a design of single-mode orbital angular momentum(OAM) beam laser with high direct-modulation bandwidth. It is a microcylinder/microring cavity interacted with two types of second-order gratings: the complex top grating containing the real part and the imaginary part modulations and the side grating. The side grating etched on the periphery of the microcylinder/microring cavity can select a whispering gallery mode with a specific azimuthal mode number, while the complex top grating can scatter the lasing mode with travelling-wave pattern vertically. With the cooperation of the gratings, the laser works with a single mode and emits radially polarized OAM beams. With an asymmetrical pad metal on the top of the cavity, the OAM on-chip laser can firstly be directly modulated with electrical pumping. Due to the small active volume, the laser with low threshold current is predicted to have a high direct modulation bandwidth about 29 GHz with the bias current of ten times the threshold from the simulation. The semiconductor OAM laser can be rather easily realized at different wavelengths such as the O band, C band, and L band.

A novel 852-nm tunable fiber laser

We report a novel fiber laser operating at 850-nm band by using semiconductor optical amplifier and fiber grating. The laser system is stable, compact, and the operating wavelength can be tuned continuously from about 851 to 854 nm for Cs atomic clock system by stretching the fiber grating. An output power up to 20 mW is obtained with a signal-to-background ratio beyond 20 dB.

Low phase noise hybrid silicon mode-locked lasers

In this paper, we review recent results on hybrid silicon mode-locked lasers with a focus on low phase noise optical pulse generation. Taking a high level design approach to lowering phase noise, we show the need for long on-chip optical delay lines for mode-locked lasers to reach and overcome material limits. Key results include demonstration of the longest （cavity length 9 cm） integrated on-chip mode locked laser, 14 dB reduction of Lorentzian noise on a 20 GHz radio-frequency （RF） signal, and greater than 55 dB optical supermode noise suppres- sion using harmonically mode locked long cavity laser, 10 GHz passively mode locked laser with 15 kHz linewidth using on-chip all optical feedback stabilization.

The mechanism for SEU simulation by pulsed laser

To simulate single event effect (SEE) by pulsed laser is a new approach in ground-based simulation of SEE in recent years. In this paper the way in which picosecond pulsed laser interacts with semiconductor and the mechanism of SEE inducement are analyzed. Additionally, associated calculations are made in the case of Nd:YAG and Ti:Sapphire lasers generally used in experiments and silicon device, with comparisons made between the two lasers. In the meantime, the fundamental principle for determining laser parameters and their typical ranges of values are provided according to the results.

Supersymmetric microring laser arrays

A coherent combination of emission power from an array of coupled semiconductor lasers operating on the same chip is of fundamental and technological importance. In general, the nonlinear competition among the array supermodes can entail incoherence and spectral broadening, leading to a spatiotemporally unstable and multimode emission pattern and thus poor beam quality. Here, by harnessing notions from supersymmetric(SUSY)quantum mechanics, we report that the strategic coupling between a class III-V semiconductor microring laser array with its dissipative superpartner can be used to limit the number of supermodes available for laser actions to one. We introduce a novel approach based on second-order SUSY transformation in order to drastically simplify the superpartner array engineering. Compared to a conventional laser array, which has a multimode spectrum, a SUSY laser array is observed to be capable of operating in a single(transverse) supermode. Enhancement of the peak output intensity of the SUSY laser array has been demonstrated with high efficiency and lower lasing threshold, compared with a single laser and a conventional laser array. Our experimental findings pave the way towards broad-area and high-power light generation in a scalable and stable fashion.

车规级功率器件的封装关键技术及封装可靠性研究进展

半导体技术的进步推动了车规级功率器件封装技术的不断发展和完善,然而车规级功率器件应用工况十分复杂,面临高度多样化的热循环挑战,对其可靠性提出了更高的要求。因此,在设计、制造和验证阶段都必须执行更为严格的高功能安全标准。综述了车规级功率器件的封装关键技术和封装可靠性研究进展,通过系统地归纳适应市场发展需求的车规级功率器件封装结构,总结了封装设计关键技术和先进手段,同时概述了封装可靠性研究面临的挑战。深入探讨了车规级功率器件封装设计和封装可靠性的重要问题,在此基础上,借鉴总结已有的研究成果,提出了可行的解决方案。

基于图像预处理的光学元件表面粗糙度测量系统

在测量光学元件表面粗糙度时,测量结果往往比较片面,为此设计基于图像预处理技术的光学元件表面粗糙度测量系统。获取原始元件表面粗糙度干涉图像,通过对表面形貌图像实施图像去噪处理与倾斜校正处理获取滤波结果,通过自适应中值滤波算法实施图像的去噪处理。在粗糙度参数评定模块中,根据取样长度对评定长度下定义,实施光学元件表面粗糙度的全面评定。利用设计系统测量三种光学元件的表面粗糙度。实验结果表明:通过设计系统能够获取高成像质量的表面粗糙度干涉图像,实现多种元件表面粗糙度的全面测量,具有一定应用价值。

SiC激光退火欧姆接触模拟分析及实验研究

实现高可靠性、低电阻欧姆接触是获得高性能SiC功率半导体器件的前提,其直接决定功率器件的能耗水平。激光退火凭借局域化、温升快、控制灵活、精度高、连续能量输出稳定等优点,成为SiC功率器件的新一代主流退火技术。总结了近年来国内外SiC功率器件激光退火研究进展,详细模拟分析了激光退火原理中光热传输特性,设计了355 nm紫外激光退火实验系统,对Ni/SiC进行了激光退火实验,在激光能量密度为2.55 J/cm^(2)条件下,比接触电阻为9.49×10^(-5)Ω·cm^(2)。研究结果对SiC功率器件激光退火欧姆接触性能提升提供了理论和数据支撑。

Self-Collimation in Planar Photonic Crystals Fabricated by CMOS Technology

We report a self-collimating demonstration in planar photonic crystals （PhCs） fabricated in silicon-on-insulator （SOI） wafers using 0.18 μm silicon complimentary metal oxide semiconductor （CMOS） techniques. The emphasis was on demonstrating the self-collimation effect by using the standard CMOS equipment and process development of an optical test chip using a high-volume manufacturing facility. The PhCs are designed on the 230-nm-top-Si layer using a square lattice of air holes 280 nm in diameter. The lattice constant of the PhCs is 380 nm. The experimentally obtained wavelengths for self-collimation are in excellent agreement with theory.

半导体器件的封装技术与可靠性研究

文章重点探索和分析了半导体器件封装技术及技术应用的可靠性,以提升半导体器件在各种环境下高质量应用。以理论与实践相结合的方式,对半导体器件的封装技术进行分析,例如封装工艺、芯片保护、电气功能实现等技术内容,可为提升封装耐久性和稳定性提供有效途径。同时,针对封装技术应用的可靠性进行优化。研究发现应用封装材料及技术的先进性改良,可提升器件封装热循环能力、机械承受能力等,相关研究数据表明,经过优化后的半导体器件封装技术,能够延长设备自身的使用寿命,对高性能电子设备的应用提供有力技术支持。

半导体物理与器件的实验教学分析

阐述半导体物理与器件实验教学的特点,实验的教学设计与优化,包括实验课程群的融合、验证性实验向设计性实验的过渡、教研结合实现资源共享、教学模式的改进。

大功率半导体模块封装进展与展望

大功率半导体模块的发展进化是电力电子系统升级和产业发展的最关键因素。文章根据功率模块的主要应用领域分类,综述了其产品和封装技术的最新进展,分析了新型模块产品的结构和技术特点;然后提出了当前模块封装面临的技术、成本以及新型应用系统要求等方面的挑战,讨论了向高频、高温、高可靠性、模块化等方向发展的挑战;最后对大功率半导体模块的互连及连接技术、集成化和灌封材料、紧凑封装结构的中长期趋势进行了探讨和展望。