窄发散角量子阱激光器的结构设计与分析

本文对ＧａＡｓ／ＡｌＧａＡｓ量子阱结构激光器中重要的结构参数与远场垂直发散角的关系作了系统的理论计算与分析，提出了实现２０°～３０°垂直发散角的有效途径，并同时研究了对激光器的光功率限制因子、阈值电流密度等重要参数的影响．     

InGaAs/GaAs/AlGaAs应变量子阱激光器

优化设计了既能实现较小垂直方向远场发散角,又能降低腔面光功率密度的ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变层量子阱激光器,并计算了该结构激光器实现基横模工作的脊形波导结构参数。利用分子束外延生长了ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器材料并研制出基横模输出功率大于１４０ｍＷ,激射波长为９８０ｎｍ的脊形波导应变量子阱激光器,其微分量子效率为０．８Ｗ／Ａ,垂直和平行结平面方向远场发散角分别为２８°和６．８°     

小发散角量子阱激光器研究

使用三层平板波导理论分析了半导体量子阱激光器远场分布。针对大功率激光器讨论了极窄和模式扩展波导结构方法减小垂直方向远场发散角,得到了极窄波导结构量子阱激光器远场分布的简化模型,获得了垂直发散角的理论值,垂直方向远场发散角减小为28.6°;使用传输矩阵方法模拟了模式扩展波导结构量子阱激光器的近场光斑及远场分布,垂直方向远场发散角减小为16°。实验测试了极窄和模式扩展波导结构量子阱激光器的垂直发散角,理论结果与实验测试获得的发散角基本一致,实现了降低发散角的要求,获得了小发散角量子阱激光器。     

量子阱无序的窗口结构InGaAs/GaAs/AlGaAs量子阱激光器

对ＳｉＯ２薄膜在快速热退火条件下引起的空位诱导ＩｎＧａＡｓ／ＧａＡｓ应变量子阱无序和ＳｒＦ２薄膜抑制其量子阱无序的方法进行了实验研究。并将这两种技术的结合（称为选择区域量子阱无序技术）应用于脊形波导ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器，研制出具有无吸收镜面的窗口结构脊形波导量子阱激光器。该结构３μｍ条宽激光器的最大输出功率为３４０ｍＷ，和没有窗口的同样结构的量子阱激光器相比，最大输出功率提高了３６％。在１００ｍＷ输出功率下，发射光谱中心波长为９７８ｎｍ，光谱半宽为１．２ｎｍ。平行和垂直方向远场发散角分别为７．２°和３０°     

分子束外延GaAs／AlGaAs超晶格缓冲层量子阱材料的研究

采用分子束外延技术生长了ＧａＡｓ／ＡｌＧａＡｓ单量子阱得多量子阱材料。采用ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层掩埋衬底缺陷，获得的量子阱结构材料被成功地用于制作量子阱激光器。波长为７７８ｎｍ的激光器，最低阈值电流为３０ｍＡ，室温下线性光功率大于２０ｍＷ。     

InGaAs／InP分别限制量子阱激光器的阱数优化设计和实验制备

根据对ＩｎＧａＡｓＰ－ＩｎＰ分别限制量子阱激光器结构的注入效率的分析和利用Ｘ射线衍射结ＩｎＧａＡｓＰ－ＩｎＰ２０个周期的多量子阱结构异质界面的研究，设计，制备了４个阱的ＩｎＧａＡｓＰ－ＩｎＰ分别限制量子阱激光器结构，利用质子轰击制得条形激光器，阈值电流为１００ｍＡ，直流室温连续工作，单面输出外微分子效率为３６％。     

MOCVD生长带有MQB的量子阱激光器材料

用ＭＯＣＶＤ生长发射波长为８０８ｎｍ的ＡＬＧａＡｓ／ＧａＡｓ量子阱激光器材料。通过在激光器材料的波导中加入多量子势垒（ＭＱＢ）层，有效地限制电子在阱内的复合以及高能电子溢出阱外，从而降低了激光器的阈值电流，提高了它的特征温度。增加了ＭＱＢ后，器件的阈值电流密度Ｉ＿（ｔｈ）从原来的４００～６００Ａ／ｃｍ￣２下降到３００～４００Ａ／ｃｍ￣２，特征温度从１６０Ｋ提高到２１０Ｋ。     

MOCVD生长带有MQB的量子阱激光器材料

用ＭＯＣＶＤ生长发射波长为８０８ｎｍ的ＡｌＧａＡｓ／ＧａＡｓ量子阱激光器材料。通过在激光器材料的波导中加入多量子势垒（ＭＱＢ）层，有效地限制电子在阱内的复合以及高能电子溢出阱外，从而降低了激光器的阈值电流，提高了它的特征温度。增加了ＭＱＢ后，器件的阈值电流密度Ｉｔｈ从原来的４００￣６００Ａ／ｃｍ＾２下降到３００￣４００Ａ／ｃｍ＾２，特征温度从１６０Ｋ提高到２１０Ｋ。     

低阈值基横模脊形波导GaAs／AlGaAs单量子阱激光器

本文报道了脊形波导结构ＧａＡｓ／ＡｌＧａＡｓ量子阱激光器的研究成果．我们采用湿法化学腐蚀方法，通过对器件结构参数的优化，制备了性能优越的脊形波导ＧａＡｓ／ＡｌＧａＡｓ量子阱激光器，器件的阈值电流低于１０ｍＡ，最低值为７．３ｍＡ，而且实现了基横模工作，这是国内报道的该结构激光器的最好水平．     

具有GRIN—SCH量子阱结构激光器光波导及光场特性分析

本文给出了具有ＧＲＩＮ－ＳＣＨ结构量子阱激光器的光波导模型和详细的数值计算方法,并计算分析了ＡｌｘＧａ１－ｘＡｓＧＲＩＮ层中Ａｌ浓度和ＧＲＩＮ层厚度对等效折射率的影响,给出了ＧＲＩＮ层厚的最佳值范围;给出了宽接触ＩｎＧａＡｓ／ＡｌＧａＡｓＧＲＩＮ－ＳＣＨ量子阱激光器的近场分布三维图形,并由近场分布通过快速傅里叶变换求出了远场分布。计算得到的近、远场分布图形与实际器件测试得到的结果相符合。     

A novel cladding structure for semiconductor quantum-well laserswith small beam divergence and low threshold current

A novel cladding structure is proposed and analyzed for semiconductor quantum-well lasers to achieve a small vertical-beam divergence and a low threshold current density simultaneously. This cladding structure is designed to guide a wide optical mode but with a high peak intensity in quantum wells. The wide expansion of the optical mode results in a small beam divergence. In addition, the high optical Intensity in quantum wells causes a low threshold current density. This novel cladding structure is optimized. The result shows that this type of cladding structures can achieve a beam divergence as small as 14.6° while the threshold current density remains small     

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。     

Top-surface-emitting GaAs four-quantum-well lasers emitting at 0.85 mu m

Room temperature CW and pulsed lasing of top-surface emitting, vertical-cavity, GaAs quantum-well lasers was achieved at approximately 845 nm. The active gain medium was four 100 AA thick GaAs quantum wells. The whole structure was grown by molecular beam epitaxy. Deep H/sup +/-ion implantation followed by annealing as used to control a vertical profile of resistivity for an efficient current injection at the active region. The threshold current was 2.2 mA for CW and pulsed operation using 10 mu m diameter lasers. Differential quantum efficiency was about 20%. Minimum threshold current density per quantum well of 360 A/cm/sup 2/ was obtained.<>     

Low threshold current density operation of GaInNAs quantum welllasers grown by metalorganic chemical vapour deposition

A metal organic chemical vapour deposition grown GaInNAs quantum well laser emitting at 1.25 μm is reported. The lowest threshold current density obtained by 50 μm wide stripe lasers was 340 A/cm² for a cavity length of 1420 μm. Which is almost comparable to the lowest value reported for GaInNAs lasers grown by molecular beam epitaxy. The threshold current density per well was 170 A/cm², which is the lowest threshold value reported to date     

High Efficiency Al-Free 980nm InGaAs/InGaAsP/InGaP Strained Quantum Well Lasers

High efficiency Al-free InGaAs/InGaAsP/InGaP lasers emitting at 980nm are fabricated by MOCVD. The lasers exhibit a high internal quantum efficiency of 95 % and a low internal loss of 1.8 cm-1. Low threshold current density of 190A/cm2 and high slope efficiency of 1.06W/A are obtained by lasers with 800μm cavitylength. A high characteristic temperature 210C is also obtained by replacing the GaAs barrier with high-bandgap InGaAsP barrier. The measured vertical and parallel divergence angle are 40° and 8°, respectively.     

Graded barrier single quantum well lasers--Theory and experiment

Optical gain characteristics of quantum well heterostructure lasers are investigated in a broad range from a weakly quantized system to a strongly quantized one utilizing the band-to-band model withkselection rule, the detailed band structure of the quantum well heterostructures, and degenerate statistics. The results are compared to the experimentally observed threshold current densities in graded barrier single quantum well lasers. It is found that the threshold current densities of these quantum well lasers are well explained by the theoretical results in the range of well width from 75 to 300 Å. The lowest threshold current density observed is 245 A/cm²in a heavily doped 100 Å single quantum well laser with a 150μm stripe width and 550μm length.     

High-quality 1.3 /spl mu/m GaInNAs single quantum well lasers grown by MBE

High-quality 1.3 /spl mu/m GaInNAs/GaNAs single quantum well lasers grown by molecular beam epitaxy are reported. The broad area lasers show a record low threshold current density of 318 A/cm/sup 2/ for a cavity length of 1 mm, a transparent current density of 84 A/cm/sup 2/, and a characteristic temperature of 103 K from 8 to 70/spl deg/C.     

High performance 1.28 /spl mu/m GaInNAs double quantum well lasers

The use of multiple quantum wells and GaAs barriers favours the temperature stability and modulation bandwidth of GaInNAs lasers. It is shown that a very low threshold current density and a high characteristic temperature can be achieved for GaInNAs/GaAs double quantum well lasers, emitting at 1.28 /spl mu/m, when grown by molecular beam epitaxy under favourable conditions.     

High-performance long-wavelength InGaAs=GaAs multiple quantum-well lasers grown by molecular beam epitaxy

High-quality 1.2 mum InGaAs/GaAs single and triple quantum-well lasers grown by molecular beam epitaxy are demonstrated. For the triple quantum well, a record low threshold current density of 107 A/cm² /well is achieved for a 100 times1000 mum laser