边发光型高速发光管电极条宽度对近场特性的影响

本文介绍了测量高速发光管的近场光强分布、发光区发光宽度和发光面积的方法;分析了电极条宽度不同时器件的发光宽度、发光面积和发散角随注入电流的变化特性;简述了器件的响应速度与电极条宽度的关系。     

激光束诱导电流在HgCdTe双色探测器工艺检测中的应用

报道了激光束诱导电流（LBIC）在碲镉汞（HgCdTe）红外双色探测器工艺检测中的应用.通过LBIC测试,发现p型HgCdTe材料由B＋离子注入损伤形成的n区面积大于其注入面积,并获得n区横向的精确分布.同时,运用LBIC,获得了p型HgCdTe材料因不同能量的等离子体干法刻蚀诱导的刻蚀台面侧壁工艺损伤形成的n区横向分布,并得到了n区横向宽度与等离子体能量的关系.     

OLED器件电荷注入模型的MATLAB分析计算

介绍了电荷从OLED金属电极注入到一个随机跳跃体系（例如配对聚合物或分子掺杂聚合物）的模型。它包括电荷载流子从电极的费米能级到介质跳跃态分布尾态之间的注入,其结果可能是电荷载流子返回到电极,或者是受到镜像引力势的作用而形成扩散逃逸。后者类似于一维Onsager型激子解离。该模型将注入电流处理为电场、温度以及跳跃态分布能量宽度的函数。提出了OLED器件中相对电流密度的概念。介绍了用MATLAB软件分析计算该模型的方法和技巧。     

应用于硅基等离子天线的横向PIN二极管的研究

介绍了横向PIN二极管及其在硅基等离子天线方面的应用,用一维理论分析了载流子大注入情况下横向PIN二极管本征区载流子浓度分布.对横向PIN二极管进行了物理建模,仿真分析了本征区长度、二氧化硅埋层、电极长度、结区掺杂浓度及表面电荷对横向PIN二极管本征区载流子浓度的影响,总结了横向PIN二极管的一般设计规则.     

隧道带间耦合级联新型激光器扩展电流的优化

隧道带间耦合级联激光器采用C掺杂生长隧道结,由于高浓度C掺杂层在激光器多个有源区之间分布形成了高电导层,增加了注入电流的横向扩展,使激光器的性能不能充分发挥出来。我们利用双面电极新型结构可以很好地克服横向电流扩展,使级联的激光器保证充分的光输出功率,具体是在常规激光器背面衬底做完全与正面电极相同而对中的电极,当加入电场后,使电场完全集中在这两个相对中的电极之间,使激光器注入的电流从正面电极完全不扩展地流入到背面衬底电极,保证每个有源区都注入相同的电流而保证每个有源区充分的光输出。对4个有源区级联的激光器光输出功率较常规电极提高70%以上,输出光功率从1.6W提高到2.4W,斜率效率提高70%以上。     

条形半导体激光器中电过程和光波导过程的精确理论

提出条形半导体激光器中稳态电过程和光波导过程及其相互作用的精确模型,并从电极电压算起得出阈值以上的电压电流分布和基模光场分布的相互影响和变化的计算机结果.指出简单的p-n结注入公式和任何固定形式的结电流分布假设对分析条形半导体激光器中的电过程和光波导过程都不适用,本文还探讨了光功率-注入电流特性出现扭折的机制和条件.     

双电极半导体光放大器的放大自发辐射谱和增益特性的实验研究

设计并制作了双电极多量子阱半导体光放大器（SOA）,对其放大的自发辐射(ASE)谱和增益特性进行了测试和分析。结果表明,注入电流密度分布对多电极SOA的ASE谱和增益特性有非常大的影响。通过调节注入电流密度比,ASE谱的半高全宽、峰值波长、峰值功率以及增益特性能够得到很好的调控。     

电极条形双区共腔半导体双稳态激光器静态和瞬态行为的精确理论计算

提出考虑到载流子侧向扩散分布以及光场模式分布精确描述具有非自建增益波导的电极条形双区共腔半导体双稳态激光器中物理过程的理论模型,从外加电极等势体出发对所涉及各种分布,不作任何人为假设,自洽地计算分析了半导体激光双稳态的静态特性和开关过程,并与现行集中均匀近似假设的计算结果进行比较,并指出其局限性。发现载流子侧向扩散分布和光场模式分布及其相互作用使激射阈值电流显著提高,双稳区宽度减小,开关时间加长。指出采用自建拆射率波导结构可明显改进双稳态性能。     

一种高辐射率的GaAs-AlGaAs双异质结侧面发光二极管

永川光电研究所去年研制成功了一种高辐射率的GaAs-AlGaAs双异质结侧面发光二极管,它采用了SiO_2掩蔽的条形电极结构。在掺硅的N型GaAs单晶的<100>面上相继外延生长出N型Al_xGa_(l-x)As,P型Al_yGa_(l-y)As,P型Al_xGa_(l-x)As和P型GaAs四层外延层,所构成的双异质结来实现对光和载流子的纵向限制;在P型面上进行闭管Zn扩散,然后溅射出厚为0.4μm的SiO_2层,光刻出宽度为60μm的电极引线条,这样来实现对光和载流子的横向限制。有源区掺硅的厚度为0.3μm左右。解理出的管芯的宽度对     

大功率670nm半导体激光器的研制

采用低压金属有机化学气相沉积生长了670nm激光器外延片，有源区采用单量子阱结构，阱区、垒区分别为InGaAsP和AlGaInP. 利用该外延片制作了带无电流注入区的氧化物条形激光器. 激光器腔长为900μm，电流注入区条宽为100μm，两端的无注入区宽度均为25μm. 镀膜后器件的阈值电流为0.4A，输出波长670±2nm，最大输出功率为1100mW, 水平、垂直发散角分别为8°, 40°. 表明该种结构可以提高器件的腔面光灾变功率.     

Numerical solution of lateral current spreading and diffusion in near-threshold DH twin-stripe lasers

A numerical solution is presented to the problem of lateral current spreading in double heterostructure twin-stripe lasers when lateral diffusion of carriers and bimolecular recombination effects are present. The current components flowing into both the p-type confining layer and the active layer are solved simultaneously, subject to the boundary conditions imposed at the heterojunction. This yields the two-dimensional potential and the current density distributions in the p-type confining layer and the lateral carder density distribution in the active region. Diffusion and bimolecular radiative recombination effects are included in the solution of the current distribution in the active layer. The lateral current and carrier density distributions along the active layer are presented for single- and twin-stripe devices for a variety of electrode injection currents. The paper highlights the influence of device geometry and diffusion on the carrier distributions found beneath the stripes of twin-stripe lasers.     

Proposal of a new method for narrowing and moving the stimulated region of cochlear implants: animal experiment and numerical analysis

We have proposed the tripolar electrode stimulation method (TESM) for narrowing the stimulation region and continuously moving the stimulation site for cochlear implants. The TESM stimulates the auditory nerve array using three adjacent electrodes which are selected among the electrodes of an electrode array within the lymphatic fluid. Current is emitted from each of the two lateral electrodes and received by the central electrode. The current received by the central electrode is made equal to the sum of the currents emitted from the lateral electrodes. In this paper, we evaluate whether or not TESM works according to a theory which is based on numerical analysis using an electrical equivalent circuit model of the auditory nerve fibers. In this simulation, the sums of the excited model fibers are compared to the compound action potentials (CAP's) which we obtained through animal experiments. To identify the main parameter while maintaining the amplitude of the CAP (the sum of the fired fibers), we assumed the presence of some parameters from the radial current density profile. In the case of the width value among the parameters being kept constant, the amplitude of the CAP was almost constant; thus, the number of the fired fibers was also almost constant. The width value equals the distance between the points at which the profile of the radial current density of the electrode array and the line of the radial threshold current density of the electrode array intersect. It is possible to determine the measure of the stimulation region or site by controlling the width value and the ratios of the currents emitted from the lateral electrodes. As a result, we succeeded in narrowing the stimulation region by controlling the sum of the currents emitted from the two lateral electrodes. Also we succeeded in continuously moving the stimulation site by modifying the currents emitted from the two lateral electrodes.     

Interstripe coupling and current spreading in a subthreshold double heterostructure twin stripe laser

TWin stripe laser structures show great promise in integrated optics Systems. It has been proposed that optical interactions in such Structures should produce properties such as beam steering, optical pulse generation and bistability. However, fundamental properties of these devices, including the effect of the resistive p-type cladding layer on the current density distribution injected into the active region, the terminal behavior of the device, and the effect of the stripe width and spacing current density distributions have not yet been considered. This paper considers the current density distribution problem of a twin stripe laser, and examines the effect on the distribution of current injection into both stripes, interstripe coupling via the resistance of the p-type cladding layer and the geometric factors of cladding layer thickness, electrode width and spacing. A diode model is assumed for the heterostructure, and finite difference techniques are used to calculate the 2 D potential distribution in the p-type cladding layer and the current density distribution in the active layer. Numerical and experimental results highlight the effect of the nonlinear diode boundary on the current density distribution and show the changes in the current distribution which occur for relatively small fluctuations in current injected into the stripes and equally small changes in the geometry.     

Comparison of contact designs for improved stability of broad areasemiconductor lasers

Patterned electrode designs are used to control optical mode shape in high-power semiconductor lasers by localizing current injection. In this letter, we present comparison of current density profiles in the active layer achieved by different contact designs. Single-voltage digitated contact, distributed regular and random Gaussian contact configurations are studied using numerical solutions of semiconductor device equations that govern electrostatic potential and carrier concentrations in three spatial dimensions. The results of our calculations indicate that lateral current profile is influenced by the contact shape in the transverse direction and the thickness of the junction on the contact side     

InGaAsP/InP Buried‐Ridge Waveguide Laser with Improved Lateral Single‐Mode Property

A novel InGaAsP/InP buried‐ridg waveguide laser diode structure is proposed and demonstrated for use as a single‐mode laser. The lateral mode of the proposed device can be controlled by adjusting the composition and thickness of the InGaAsP layer grown over the active region. Stable single‐mode operation without kinks or beam‐steering is achieved successfully with lateral and transverse in the junction plane even for the device with the ridge width of 9 μm up to an injection current of 500 mA.     

LD条宽对激射波长影响的研究

报道了LD激射波长会随条宽发生明显变化.对有相同外延生长结构和制作工艺、不同条宽的960 nm LD的激射波长进行研究发现,条宽为130、100、75和50 μm的器件的激射波长依次变短.进一步分析认为,这是因为条宽变窄导致器件阈值电流密度、阈值载流子密度变大造成的.根据GaAs材料在不同注入载流子密度下的增益谱及器件条宽变化对阈值载流子密度的影响,可以对实验现象进行合理的解释,从而在器件研制中可通过改变条宽对器件的激射波长在一定范围内进行调节.     

Enhanced carrier injection efficiency from lateral current injection in multiple-quantum-well DFB lasers

A bidimensional simulation shows that the lateral carrier injection in etched active region of multiple-quantum-well DFB lasers represents a large fraction of the injected current, leading to improved carrier homogenization in the wells. This increases the average carrier density substantially and provides a much higher gain for the same injected current, depending on detailed device structure.     

光子晶体调制半导体激光器侧模

为了实现半导体激光器的单侧模稳定工作,提出了一种在激光器的脊条两侧引入光子晶体结构滤除半导体激光器高阶侧模的方法。通过调整激光器上表面的刻蚀深度、光子晶体区域的条宽和间隔来改变激光器内部的模场分布,同时结合选择性的载流子注入来增强基模的激射优势,进而减少侧模的数量。实验上制作了主脊条宽度为6 m,光子晶体周期5 m,波长1 550 nm的半导体激光器。测试结果表明:在连续工作的情况下,电流300 mA的时候,高阶侧模受到抑制,水平发散角变为10.2,证实了光子晶体结构调制激光器侧模的可行性。     

Effect of waveguiding properties on the axial mode competition in stripe-geometry semiconductor lasers

Based on the multimode rate equations taking account of transverse mode and carrier density distributions, the axial mode behavior in semiconductor lasers is investigated. The axial mode stability is significantly affected by these distributions. Above threshold, because of hole burning in the carrier density distribution, the gain at any wavelength except the lasing wavelength does not maintain the value at threshold. If the nonlasing mode wavelength is located in the gain decreasing spectral region, its light output decreases with the increase of current. These characteristics are observed in the experiment for a CSP laser. For axial mode stabilization, a large built-in refractive index step is effective so long as single transverse mode operation is maintained. If the injection current region is defined separately from the guiding region, the wider width of the injection current region leads to a more stabilized axial mode.     

Channeled substrate nonplanar laser analysis--Part II: Lasers with tapered active regions

Light versus current (LversusI) characteristics are calculated for double-heterostructure diode lasers whose active regions decrease in thickness laterally from a maximum on axis. This variation produces lateral real refractive index waveguiding which in turn stabilizes the spatial mode such that the modal field becomes anastigmatic and theLversusIplot becomes linear. In addition to determining threshold current and differential quantum efficiency, we compute the TE00mode patterns, active region charge density distribution, and the power levelP*_{1}at which spatial hole burning causes the TE01mode to begin lasing. The maximum power density at the facet for that power levelP*_{1}is also obtained. All these characteristics are presented as functions of the various device parameters including carrier spontaneous recombination time, diffusion length, optical gain, unpumped band-to-band absorption, internal losses, antiguidance index, wavelength, cladding Al content, active region dimensions, current spreading resistance, facet reflectivity, laser length, and stripe width. Utilizing this information, a design is developed for a laser with low threshold current (40-50 mA) and high differential quantum efficiency (50-65 percent) that operates stable single lowest order (TE00) spatial mode to powers well in excess of 50 mW.