低波长漂移的电吸收调制DFB激光器

采用端面有效反射率法 ,从理论上计算了单片集成电吸收调制 DFB激光器 (Electroabsorption ModulatedDFB L aser,EML)的腔面反射率、耦合强度 (κL)对其波长漂移的影响 .同时在实验中通过改变腔面的反射率来验证计算结果 .理论与实验的结果表明 :为提高 EML 的模式稳定性 ,必须减小调制器一端的反射率 ,同时增加DFB激光器的 κL.最终我们采用选择区域生长 (Selective Area Growth,SAG)的方法 ,制作了低光反馈出光面的单脊条形 EML,在 2 .5 Gb/ s的非归零 (NRZ)码调制下 ,经过 2 80 km的标准光纤传输后 ,没有发现色散代价 .     

低波长漂移的电吸收调制DFB激光器

采用端面有效反射率法,从理论上计算了单片集成电吸收调制DFB激光器（Electroabsorption Modulated DFB Laser,EML）的腔面反射率、耦合强度（κL）对其波长漂移的影响.同时在实验中通过改变腔面的反射率来验证计算结果.理论与实验的结果表明：为提高EML的模式稳定性,必须减小调制器一端的反射率,同时增加DFB激光器的κL.最终我们采用选择区域生长（Selective Area Growth,SAG）的方法,制作了低光反馈出光面的单脊条形EML,在2.5Gb/s的非归零(NRZ)码调制下,经过280km的标准光纤传输后,没有发现色散代价.     

ZnSe基蓝绿色半导体激光器研究进展

在全彩色显示,高密度激光存储,高速打印,高分辨图像处理和战地生化检测等强力推动下,ＺｎＳｅ基蓝绿色半导体激光器的研究近年来取得了里程碑式的研究结果。为了明确该领域的研究方向,以便分析在实用化进程中必须解决的主要问题。本文对ＺｎＳｅ基蓝绿色半导体激光器及其相关材料的研究进展进行了较全面的评述,作为比较,对ＧａＮ基蓝绿色半导体激光器的发展情况和尚待解决的问题也进行了简要评述。     

放大自发辐射注入波长锁定法布里-珀罗激光器

波分复用无源光网络(WDM-PON)被认为是接入网的最终解决方案,基于放大自发辐射(ASE)注入波长锁定法布里-珀罗(F-P)激光器的WDM-PON由于其价格低廉和容易实现颜色无关操作而受到极大关注.实验研究了ASE注入波长锁定F-P激光器的ASE增益、边模抑制比(SMSR)和相对强度噪声(RIN)随F-P激光器注入电流和ASE注入功率的变化关系,理论模拟了ASE注入功率和增益一定时,F-P激光器注入电流随其前端面反射率的变化关系,并从实验上进行了验证.研究结果表明,当F-P激光器的注入电流为阈值电流的1.3～1.7倍时,能获得满足应用需要的相对强度噪声和边模抑制比.对于一定的ASE注入功率和输出功率,存在使注入电流最小的最佳前端面反射率.     

Be基蓝绿激光器载流子约束的LCAO理论研究

本征的强离子性，使ZnSe基半导体蓝绿激光器易于形成堆垛层错等退化缺陷，严重地影响了器件的寿命。人们便开始将注意力投向离子性较低的Be基化合物，希望用Be基Ⅱ-Ⅵ族材料取代ZnSe基材料，抑制蓝绿激光器的退化。要研制半导体激光器，电学限制层对发光活性层中载流子的约束能力（即能带的offset值）是最重要的基本参数之一。由于对Be基化合物的了解十分有限，本文从基本的原子参数出发，用原子轨道线性组合（LCAO）理论计算了所有Ⅱ-Ⅵ族化合物价带顶的相对位置，结合带隙的实验值，给出了Ⅱ-Ⅵ族化合物导带底的相对位置。简要分析了二元化合物用于BeTe中载流于约束的可能性。根据虚晶近似，用插值方法计算了与GaAs匹配的Be基四元合金相对与BeTe价带、导带的offset。对各四元合金的特征进行了分析对比，讨论了Be基四元合金用作我流子约束层的可能性。为制作Be基半导体蓝绿激光器提供了能带剪裁的理论依据。     

Defect Imaging in Laser Diodes by Mapping Their Near-Infrared Emission

We report additional infrared (IR) emission bands at about 1.0 eV and 1.4 eV from GaAs-based diode lasers that have their primary emission at 808 nm (1.53 eV). Four long-wavelength bands are observed. They are assigned to bandtail-related luminescence from the quantum wells (QW) as well as to interband- and deep-level-related luminescences from the GaAs substrates. Thermal radiation is detected below 0.4 eV as well. By using a thermocamera, the defect-related emission was mapped for different types of high-power diode lasers. The mechanisms causing enhanced IR emission from the devices and potential applications of this type of monitoring are addressed.     

GaN基近紫外激光器研究现状与进展

氮化镓(GaN)基近紫外激光器(UVA LD,320～400 nm)在紫外固化、3D打印以及医疗等领域具有广泛应用。文章首先概述了GaN基UVA LD的国内外研究现状与关键技术挑战,然后分析了如何从外延生长与结构设计的角度,解决AlGaN的应力调控、高效p型掺杂与量子阱中极化电场的抑制等关键问题,以期为进一步实现高功率、低阈值、长寿命GaN基UVA LD的外延生长提供参考。     

LD 双向泵浦、LBO 腔内倍频绿光激光器

采用两支国产2W单芯半导体激光器(Diode Laser)作泵浦源，双向端面泵浦Nd：YVO4晶体，由Ⅰ类临界相位匹配LBO晶体腔内倍频，采用Z型谐振腔结构，在泵浦功率为3．12W的条件下，得到功率为670mW的TEM00模稳定绿光输出，测量表明4h功率稳定性优于3％，偏振比大于500：1，振幅噪声小于0．5％。     

耦合腔激光器的波长调谐与频率调制特性分析

考虑用激光器与调制器直接耦合以及耦合槽的影响，用散射矩阵法及二步等效反射率法，对沟槽耦合腔激光器的波长调谐和频率调制特性的分析表明，数学处理简单，物理图像清晰。     

三相移分布反馈激光器的静态及动态特性分析

提出了一种新的分布反馈 (DFB)激光器的传输矩阵 (TMM)分析方法──向量法 ,并建立了一个新的小信号分析模型。利用向量法及小信号分析模型 ,考虑了空间烧孔 (SHB)及非线性增益的因素 ,分析了三相移分布反馈激光器 (3PS DFB)的静态及动态特性 ,得出不同电流注入情况下的载流子密度及光子密度的轴向分布。此分析方法亦可用于其他DFB结构的分析     

Cavity-Resonant Behaviors of All-Optical Synchronization and Clock Recovery in Passively Mode-Locked Laser Diodes

We experimentally and theoretically investigated the synchronization characteristics in all-optical synchronization and clock recovery of the passively mode-locked laser diode (MLLD), and the relationship with the optical-cavity resonant behaviors of the input optical signals in the cavity of the MLLD. The dependences on the wavelength detuning, the data format, the injection power, the mark-to-space ratio, the input data pattern, and the intensity fluctuations of the injected optical signals were experimentally discussed in detail. It was clearly concluded from the experimental results that the optical cavity-resonant behavior of the incoming optical signals in the cavity of the MLLD was a determinant factor of the locking mechanism in the all-optical synchronization of the MLLD and that the optical-injection locking mechanism was not a dominant effect. The experimental results were examined based on a simple theoretical model including the enhancement of the effective modulation due to the optical-cavity resonance. By using the model we succeeded in explanation of the trends of the experimental results.     

包层介质折射率引起的回音壁模式光纤激光波长漂移

将直径为93um的石英光纤浸入低折射率的若丹明6G乙醇和乙二醇混合溶液中,采用沿光纤轴向光抽运消逝波激励染料增益的方式.研究回音肇模式(WGM)激光辐射的波长随染料混合溶液折射率变化的特性.实验发现,随染料混合溶液折射率的增加,回音壁模式激光辐射的波长向短波方向移动.用回音壁模式染料激光的四能级模型得到激光上能级和所有能级上的分子数比值rO曲线后,很好地解释了实验结果.     

High-Temperature High-Power Operation of GaInNAs Laser Diodes in the 1220–1240-nm Wavelength Range

We report on the high-temperature performance of high-power GaInNAs broad area laser diodes with different waveguide designs emitting in the 1220–1240-nm wavelength range. Large optical cavity laser structures enable a maximum continuous-wave output power of $>$8.9 W at ${T}=20 ^{circ}$C with emission at 1220 nm and are characterized by low internal losses of 0.5 cm$^{-1}$ compared to 2.9 cm$^{-1}$ for the conventional waveguide structures. High-power operation up to temperatures of 120 $^{circ}$C is observed with output powers of $>$4 W at ${T}=90 ^{circ}$C. This laser diode showed characteristic temperatures of ${T}_{0} =112$ K and ${T}_{1}=378$ K.      

Emission Wavelength Tuning via Competing Lattice Expansion and Octahedral Tilting for Efficient Red Perovskite Light-Emitting Diodes

The band-edge electronic structure of lead halide perovskites (ABX₃) is composed of the orbitals of B and X components and can be tuned through the composition and structure of the BX₆ octahedron. Although A-site cations do not directly contribute to near-edge states, the bandgap of 3D metal halide perovskites can be affected by A-cations through BX₆ octahedron tilting or lattice size variation. Here, as confirmed by the Rietveld refinement results of X-ray diffraction characterization, the competition between lattice expansion and octahedral tilting is identified for the first time in emission wavelength tuning when introducing a large A-site cation (C₂H₅NH₃⁺, EA⁺) into 1-naphthylmethylammonium iodide-passivated CsPbI₃ system. The former dominates spectral redshift, while the latter leads to a blueshift of emission peak, which broadens the way to tune the emission wavelength. In addition, excess cations can also passivate the perovskites, leading to a photoluminescence (PL) quantum yield as high as 61%, increased average PL lifetime of 74.7 ns, and a high radiative and non-radiative recombination ratio of 15.7. Eventually, spectral-stable deep-red perovskite light-emitting diode with a maximum external quantum efficiency of 17.5% is realized, which is one of the highest efficiencies without using any light outcoupling and anti-solvent techniques.     

Effect of the Phase Shift in a Periodic Anode on the Emission Spectra of Top-Emitting Organic Light-Emitting Diodes

Top-emitting organic light-emitting diodes with an Al–Ag cathode and $hbox{Al}+(hbox{Ni}hbox{–}hbox{Au})_{n}$ anode were proposed and fabricated. The multiple layered anode results in a phase shift at the metal interfaces. It was also found that theoretically calculated peak wavelengths of the intensity spectra agree well with those experimentally measured from the fabricated devices. These results also indicate that the phase shift effect in periodic anode is important for microcavity devices.      

半导体LD在光通信以外的部分应用

文中介绍半导体激光二极管在信息传输以外的部分应用。随着激光二极管工艺和器件发展,他们在光通信以外的市场不断扩大,应用越来越广泛。本文介绍 LD 在医疗、测量、条形码扫描仪,以及光谱学方面的应用。     

激光角膜矫正术中所用激光波长的选择

用分光光度计测定了12例兔角膜和1例人角膜的吸收光谱,结果表明波长小于300nm的准分子激光和波长在1.88μm～2.64μm,2.36μm～40μm的激光,均可对角膜进行切割并可望用于激光角膜矫正术。     

蓝色波段发光和激光二极管的新进展

文章在简要概述了几种适合制备短波长发光器件材料－ＳｉＣ，ＧａＮ和ＺｎＳｅ的晶体结构、掺杂性质及外延技术后，主要介绍了它们在制备蓝色波段发光和激光二极管的新进展。     

无铟激光二极管成功制备

Hamamatsu的研究人员报道了一种无In的激光二极管，工作波长在342nm，这是迄今为止波长最短的电驱动半导体激光二板管。