Laterally Coupled DFB Lasers for One-Step Growth Photonic Integrated Circuits in InP

Design and characterization of a transmitter building block for one-step growth photonic integration, featuring a 1310 - nm laterally coupled distributed-feedback laser with a front-side passive optical waveguide and a back-side optical power monitor, are presented. Formed on a semi-insulating Fe : InP substrate and processed by means of a stepper optical lithography, the device perfectly suits the multiguide vertical integration-a newly developed one-step growth photonic integrated technique in InP.     

锗基InAs量子点激光器的腔面失效及再生的研究

围绕锗基InAs量子点激光器,开展了激光器腔面失效及再生的研究.研究并分析了灾变性光学镜面损伤产生的机理及其对激光器腔面的影响,开展了腔面再生研究,发展了一套创新性的腔面再生工艺并实现了失效的锗基InAs量子点激光器的再生.根据锗基InAs量子点激光器材料结构设计腐蚀工艺,通过选择性腐蚀在激光器腔面制备出悬臂结构,采用细针解理使悬臂结构自然解理,获得新的激光器谐振腔面,失效激光器重新工作.对比了激光器失效前和再生后的工作性能,结果表明因灾变性光学镜面损伤而失效的锗基InAs量子点激光器获得全新的谐振腔面,锗基激光器器件性能和失效前相当.     

MOVPE生长1.3 μm无致冷AlGaInAs/InP应变补偿量子阱激光器研究

通过低压金属有机化学气相外延 (LP MOVPE)工艺生长了AlGaInAs应变补偿量子阱材料 ,通过X射线双晶衍射、光荧光、二次离子质谱的测试分析得到了材料生长的优化工艺参数 ,降低了材料中的氧杂质含量 ,得到了高质量AlGaInAs应变补偿量子阱材料 ,室温光致发光半宽FWHM =2 6meV。采用此外延材料成功制作了 1 3μm无致冷AlGaInAs应变量子阱激光器 ,器件测试结果为 :激射波长 :12 90nm≤ λ≤ 1330nm ;阈值电流 :Ith(2 5℃ )≤15mA ;Ith(85℃ )≤ 2 5mA ;量子效率变化 :Δηex(2 5～ 85℃ )≤ 1 0dB。     

InAs/InP Quantum-Dash Lasers and Amplifiers

InAs quantum-dash structures fabricated by self-assembly growth techniques and based on compound semiconductors lattice matched to InP substrates were used to realize long wavelength lasers and amplifiers for telecom applications. With this new type of laser material special properties of low-dimensional electronic systems can be utilized for device applications, which allow to realize new device features not possible by conventional device designs. In this paper a brief overview is given about application oriented material and device research on this wire/dot-like material system by highlighting laser and high-speed optical amplifiers. Broadband laser material with a gain bandwidth of more than 300 nm could be obtained to cover the extended telecommunication wavelength range between 1.4 and 1.65 . High-speed optical amplifiers could be realized by using this quantum-dash laser material with unique device performance, like multiwavelength amplification without any cross-talk at data rates of 10 Gbit/s and pattern-free and noise reduced signal amplification at saturation condition demonstrated up to 40 Gbit/s.     

基于InP衬底的GaAsSb/InP异质结晶体管

采用金属有机化学气相沉积生长了InP/GaAs0.5Sb0.5/InP 双异质结晶体三极管(DHBT)材料,研究了材料质量对器件性能的影响.制备的器件不但具有非常好的直流特性,而且还表现出良好的微波特性,其结果与能带理论的预言一致,DHBT集电结和发射结的电流理想因子分别为1.00和1.06,击穿电压高达15V,电流放大增益截止频率超过100GHz.     

基于InP衬底的GaAsSb/InP异质结晶体管

采用金属有机化学气相沉积生长了InP/GaAs0.5Sb0.5/InP 双异质结晶体三极管(DHBT)材料,研究了材料质量对器件性能的影响.制备的器件不但具有非常好的直流特性,而且还表现出良好的微波特性,其结果与能带理论的预言一致,DHBT集电结和发射结的电流理想因子分别为1.00和1.06,击穿电压高达15V,电流放大增益截止频率超过100GHz.     

Temperature dependence of photoluminescence of QD arrays

It is essentially important to understand the temperature dependence of the photoluminescence of multimodal quantum dot (QD) arrays for the realization of efficient photonic devices. In this paper, the dynamics processes of different density multimodal QD arrays were fitted by using the rate equation model. It is shown that, in high density QD arrays, the intensity of photoluminescence of different QD families has different temperature dependence, and the intensity of photoluminescence is quenched as the temperature increases in low density QD arrays. In high density QD arrays, as the temperature increases, the carriers will be thermally excited into the wetting layer from QDs, and then some of them will be recaptured by the big scale QDs; carrier coupling takes place between the different QD families, while in low density QD arrays, the carrier transfer between different QD families will be limited. Temperature dependence of the maximum of the ratio of photoluminescence intensity of different QD families strongly depends on the difference of thermal activation energies.     

高频大功率InGaAsP/InP SPB-BC激光器

在普通掩埋新月型激光器的基础上,提出了一种高频大功率的InGaAsP/InP激光器结构——选择性质子轰击掩埋新月型(SPB-BC),并对激光器结构模型进行了理论分析。采用p-InP衬底,最大输出功率为80mW。500μm腔长激光器,它的调制带宽可以达到6.0GHz。     

Investigation on the Multimode Dynamics of InGaAsP–InP Microring Lasers

A multimode model based on the rate equation approximation is presented in order to simulate the mode dynamics of 1.55-mum InGaAsP-InP microring lasers. A detailed characterization is performed including calculated optical spectra, time traces and relative intensity noise spectra. Different operation regimes are observed, bidirectional multimode with/without alternate oscillations, unidirectional single mode, bidirectional single mode and mode hopping. The boundaries of the above operation regimes are investigated with respect to the current level, bus waveguide reflectivity and ring radius. Varying the current level a transition from multimode to single mode and eventually mode hopping operation is observed. Increasing the bus waveguide reflectivity a transition from unidirectional to bidirectional operation is revealed, while the use of nonequal reflectivities between the two facets, promotes unidirectional operation. Moreover, the ring radius is proved to be a critical parameter for the extent of each operation regime since it directly influences the modal wavelength separation     

InGaAsP／InP激光器非平面液相外延生长的研究

本文叙述了用于制作 InGaAsP/InP 半导体激光器的非平面液相外延工艺。讨论了各种因素对非平面液相外延生长的影响。在 InP 衬底上和刻有沟槽的 InGa-AsP/InP 外延片上成功地生长出了高质量外延层。用该外延片制作的激光器在室温连续工作条件下典型阈值电流30mA,典型输出功率为10mW。最高激射温度为115℃。     

生长温度对类金刚石膜结构和发光性质的影响

使用脉冲激光沉积技术制备了系列无氢类金刚石薄膜,测量了样品的Raman光谱、光吸收光谱和光致发光光谱,研究了薄膜结构和光致发光性质与制备条件的依赖关系。结果表明,这种薄膜是由少量sp2键和大量sp3键组成的非晶碳膜。薄膜的光学带隙在1.68~2.46eV,发光在可见光区呈宽带结构。生长温度能够对类金刚石薄膜的结构和发光性质产生较大影响。当生长温度从室温升高至400℃时,sp2团簇的变大使C原子的有序度增强,从而导致薄膜的光学带隙变窄,发光峰红移且半高宽变小。     

GaInAsP/InP材料的生长研究

用液相外延方法进行了GaInAsP/InP单异质结和双异质结材料的薄层外延生长。给出了源配制的简单公式,配制源饱和温度的精确测定,给工艺生长参数的选择带来了方便。外延层厚度与生长时间的实验关系指出,在生长时间少于40分时,实验结果与理论关系式符合。测定了InP,GaInAsP外延层掺Sn,Zn的载流子浓度和液相中组分xs_n~ι,xz_n~ι的实验关系。文章最后描述十四层双异质结外延材料的生长,给出了获得器件质量要求的GaInAsP材料的择优生长工艺条件。     

Ultimate Lasing Temperature of Microdisk Lasers

Semiconductors - A model is developed that makes it possible to analytically determine the threshold current of a microdisk laser with consideration for its self-heating as a function of the...     

Temperature dependent photoluminescence of porous InP

Temperature dependent photoluminescence (PL) spectra of porous InP prepared by wet-electrochemical techniques are presented. Compared to the PL spectra of the bulk InP wafer measured at the corresponding temperatures, two peaks are observed in porous InP. One peak, which dominates at temperatures above 150 K, shows blue shift about 14 meV, while the other peak, which dominates at temperatures below 120 K, shows red shift about 33 meV. Quantum confinement effect is assumed to be the origin of the blue shifted PL. The red shifted PL emission is very sensitive to chemical treatment and is suggested to be due to the radiative recombination via surface states.     

DFB Lasers With Deeply Etched Vertical Grating Based on InAs–InP Quantum-Dash Structures

Distributed feedback lasers with first-order vertical grating based on AlInGaAs-InAs-InP quantum-dash lasers were fabricated by electron beam lithography and Cl₂-Ar reactive ion etching with an electron cyclotron resonance source. Low threshold currents and single-mode operation with sidemode suppression ratios of 48 dB and a direct modulation bandwidth of 5.5 GHz were demonstrated     

Analysis of InP Regrowth on Deep-Etched Mesas and Structural Characterization for Buried-Heterostructure Quantum Cascade Lasers

We investigated the effect of deep-etched mesa sidewall profile and oxide overhang length on the regrowth structural characteristics for buried- heterostructure (BH) quantum cascade lasers (QCLs) grown by metalorganic chemical vapor deposition (MOCVD). The relationship between etched mesa sidewall geometry, oxide overhang length, oxide thickness, and growth uniformity was examined and is extensively discussed. In particular, anomalous growth in the vicinity of the oxide edge resulting from insufficient oxide overhang length was identified and studied. An ideal ratio of mesa height to oxide overhang length between 2.5 and 3.0 is proposed and experimentally justified to yield satisfactory planar regrowths without anomalous growth. Mesas in the [ 0 1[` 1] ] [ 0 1\overline{ 1} ] direction with smoothly etched entrant profile yield a higher degree of growth uniformity than mesas in the [011] direction with the re-entrant profile.     

Growth and Luminescence of Polytypic InP on Epitaxial Graphene

Van der Waals epitaxy is an attractive alternative to direct heteroepitaxy where the forced coherency at the interface cannot sustain large differences in lattice parameters and thermal expansion coefficients between the substrate and the epilayer. Herein, the growth of monocrystalline InP on Ge and SiO₂/Si substrates using graphene as an interfacial layer is demonstrated. Micrometer‐sized InP crystals are found to grow with interfaces of high crystalline quality and with different degrees of coalescence depending on the growth conditions. Some InP crystals exhibit a polytypic structure, consisting of alternating zinc‐blende and wurtzite phases, forming a type‐II homojunction with well (barrier) width of about 10 nm. The optical properties, investigated using room temperature nano‐cathodoluminescence, indicate the signatures of the direct optical transitions at 1.34 eV across the gap of the zinc‐blende phase and the indirect transitions at ≈ 1.31 eV originating from the alternating zinc‐blende and wurtzite phases. Additionally, the InP nanorods, found growing mainly on the graphene/SiO₂/Si substrate, show optical transition across the gap of the wurtzite phase at ≈ 1.42 eV. This demonstration of InP growth on graphene and the correlative study between the structure and optical properties pave the way to develop hybrid structures for potential applications in integrated photonic and optoelectronic devices.     

生长温度对ZnO薄膜性能的影响

采用常压金属有机化学气相沉积技术在Al2O3(0001)衬底上生长出高质量的ZnO薄膜.用X射线双晶衍射ω和θ-2θ扫描、室温光致发光研究了不同生长温度对ZnO薄膜的结构、发光性能的影响.结果表明,随着生长温度的升高,ZnO薄膜的c轴晶格常数逐渐增大,a轴晶格常数逐渐变小,同时带隙相应逐渐增大.     

生长温度对ZnO薄膜性能的影响

采用常压金属有机化学气相沉积技术在Al2O3(0001)衬底上生长出高质量的ZnO薄膜.用X射线双晶衍射ω和θ-2θ扫描、室温光致发光研究了不同生长温度对ZnO薄膜的结构、发光性能的影响.结果表明,随着生长温度的升高,ZnO薄膜的c轴晶格常数逐渐增大,a轴晶格常数逐渐变小,同时带隙相应逐渐增大.     

温度梯度对光纤激光器横向模式的影响

分析了温度梯度对光纤激光器横向模式的影响。通过建立简化的光纤截面热传导模型,得到了光纤截面温度的分布。利用场分析软件分析了在不同抽运功率、吸收系数、折射率温度系数下光纤激光器横向模式的变化,发现当抽运功率提高时,横向模式有向纤芯收缩的趋势,这可能是高功率条件下光纤激光器中高阶模式出现的原因之一。当吸收系数增加或折射率温度系数增加时,横向模式也有向纤芯收缩的趋势。