高功率14xx nm锥形增益区脊形波导结构量子阱激光器的研制

初步设计14xx nm锥形增益区脊形波导量子阱激光器材料和器件结构,利用MOCVD生长14xx nm InGaAsP/InP量子阱激光器外延片,引入腔破坏凹槽(cavity-spoiling grooves)将有源层刻蚀断以隔离从锥形区反向传输回的高阶模,进一步改善远场光束质量.保持总腔长1900μm不变,改变脊形区的长度,其长度分别为450,700和950μm.对比三种情况的最高输出功率和远场特性,发现LRW＝700μm时,器件特性参数和远场光束质量最优,斜率效率为0.32W/A,饱和输出功率为1.21W,其远场为近衍射极限的高斯分布,发散角为29°×9.6°.当固定脊形区长度为700μm,改变锥形区长度,发现当锥形区长度为1000μm时,器件特性参数进一步提高,斜率效率达0.328W/A,饱和输出功率为1.27W,远场仍为近似高斯分布.     

高功率980nm锥形增益区脊形波导量子阱激光器的优化

利用MOCVD生长980nm InGaAs-AlGaAs渐变折射率分别限制异质结单量子阱激光器外延片,采用锥形增益区脊形波导结构制备器件.保持总腔长1850μm不变,改变脊形区的长度分别为450,700和950μm,对比三种情况的P-I特性和光束质量.发现LRW＝450μm时,器件特性参数和远场光束质量最优,斜率效率达0.83W/A,饱和功率为4.28W.输出功率为1W时,远场发散角为7.5°×30.6°,M2因子为3.79.     

高功率980nm锥形增益区脊形波导量子阱激光器的优化

利用MOCVD生长980nm InGaAs-AlGaAs渐变折射率分别限制异质结单量子阱激光器外延片,采用锥形增益区脊形波导结构制备器件.保持总腔长1850μm不变,改变脊形区的长度分别为450,700和950μm,对比三种情况的P-I特性和光束质量.发现LRW＝450μm时,器件特性参数和远场光束质量最优,斜率效率达0.83W/A,饱和功率为4.28W.输出功率为1W时,远场发散角为7.5°×30.6°,M2因子为3.79.     

9.0μm锥形量子级联激光器

本文报道了波长为9.0μm的锥形量子级联激光器。与普通的脊形量子级联激光器相比,锥形量子级联激光器的水平远场发散角更小。系统的研究了锥形角度对脊形区宽度约为11μm的锥形量子级联激光器器件性能的影响,结果表明3°的锥形角是一个优化的角度,锥形角为3°时量子级联激光器具有较高的功率和仅为7.1°的水平远场发散角。     

980nm大功率基横模分布反馈激光器

980 nm波段的大功率半导体激光器作为抽运源有很重要的应用,但目前该类器件存在光束质量差和谱宽较宽的问题,影响其抽运效率和稳定性。为提高大功率半导体激光器的抽运效率,就要减小其光谱宽度,提升光束质量。而大功率基横模分布反馈激光器(DFB)通过在器件内部引入分布反馈光栅可以实现窄线宽激光的波长稳定输出,并通过优化脊型波导条件来实现基横模模式输出,提升光束质量。测试该器件的光电特性,1000μm腔长器件的阈值电流约为6 m A,斜率效率为0.71 W/A,最大稳定输出功率为130 m W。该激光器的波长随温度漂移系数为0.064 nm/K;对其远场发散角进行测量,得到快轴发散角为34°,慢轴发散角为6.3°。     

电极分离的980nm锥形激光器的研制

对脊形波导区和锥形区电极分离的980nm锥形激光器(简称电极分离的980nm锥形激光器)改变脊形波导区所加电流,测试激光器的P-I特性和光束质量因子,与脊形波导区和锥形区共用电极的980nm锥形激光器(简称电极共用的980nm锥形激光器)的测量参数进行对比.发现电极分离的980nm锥形激光器的P-I特性曲线比较光滑,没有明显的扭折.随着脊形波导区的电流逐渐超过150mA以后,器件的最大输出功率逐渐达到4.28W,与电极共用的980nm锥形激光器相同并趋于饱和,光束质量因子从3.79降到2.45(输出功率为1W).     

电极分离的980nm锥形激光器的研制

对脊形波导区和锥形区电极分离的980nm锥形激光器(简称电极分离的980nm锥形激光器)改变脊形波导区所加电流,测试激光器的P-I特性和光束质量因子,与脊形波导区和锥形区共用电极的980nm锥形激光器(简称电极共用的980nm锥形激光器)的测量参数进行对比.发现电极分离的980nm锥形激光器的P-I特性曲线比较光滑,没有明显的扭折.随着脊形波导区的电流逐渐超过150mA以后,器件的最大输出功率逐渐达到4.28W,与电极共用的980nm锥形激光器相同并趋于饱和,光束质量因子从3.79降到2.45(输出功率为1W).     

2μm InGaAsSb/AlGaAsSb应变补偿量子阱结构的数值研究

为了降低2μm半导体激光器的阈值电流并提高器件的输出功率,设计了InGaAsSb/AlGaAsSb应变补偿量子阱结构,并利用SimLastip软件对器件进行了数值模拟.研究表明,在势垒中适当引入张应变可以改善量子阱的能带结构,提高对载流子的限制能力.当条宽为120 μm、腔长为1 000 μm时,采用应变补偿量子阱结构的激光器的阈值电流为91 mA,斜率效率为0.48 W/A.与压应变量子阱激光器相比,器件性能得到明显的改善.     

低阈值高效率InAlGaAs量子阱808 nm激光器

以Al0.3Ga0.7As/InAlGaAs/Al0.3Ga0.7As压应变量子阱代替传统的无应变量子阱作为有源区,实现降低808 nm半导体激光器的阈值电流,并提高器件的效率。首先优化设计了器件结构,并利用金属有机物化学气相淀积(MOCVD)进行了器件的外延生长。通过优化外延生长条件,保证了5.08 cm片内的量子阱(QW)光致发光(PL)光谱峰值波长均匀性达0.1%。对于条宽为50μm,腔长为750μm的器件,经镀膜后的阈值电流为81mA,斜率效率为1.22 W/A,功率转换效率达53.7%。变腔长实验得到器件的腔损耗仅为2 cm-1,内量子效率达90%。结果表明,压应变量子阱半导体激光器具有更优异的特性。     

940 nm高功率半导体激光器研究

报道了一种采用大光学腔结构的InGaAs/GaAs/AlGaAs应变量子阱高功率半导体激光器。在量子阱能级本征值方程的数值求解基础上 ,优化了InGaAs阱层材料的In组份含量 ;采用大光学腔结构以有效降低垂直于结平面方向的光束发散角及腔面的光功率密度 ,实现器件的高功率、低发散角光。设计的激光器外延结构采用分子束外延 (MBE)方法生长 ,成功获得具有较低激射阈值的 94 0nm波长激光器外延片。对 10 0 μm条形 ,10 0 0 μm腔长的制备器件测试表明 ,器件的最大连续输出功率达到 2W ,峰值波长为 939.4nm ,远场水平发散角为 10° ,垂直发散角为 30°。器件的阈值电流为 30 0mA。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.