High-Efficiency 808-nm InGaAlAs–AlGaAs Double-Quantum-Well Semiconductor Lasers With Asymmetric Waveguide Structures

The InGaAlAs-AlGaAs double-quantum-well semiconductor lasers grown by molecular beam epitaxy show high quantum efficiency and high power conversion efficiency at continuous-wave power output using asymmetric waveguide structures. The threshold current density and slope efficiency of the device are 180 A/cm² and 1.4 W/A, respectively. The internal loss and the internal quantum efficiency are 1.1 cm^-1 and 97%, respectively. The 75% maximum power conversion efficiency is achieved in 100-mum stripe widths 808-nm-emitting laser diodes with 1000-mum cavity length.     

Gain-shifted TDFA employing high concentration doping techniquewith high internal power conversion efficiency of 70%

The amplification characteristics of a high Tm³⁺ concentration gain-shifted Tm-doped fluoride fibre amplifier (GS-TDFA) have been determined with a high input signal power. This GS-TDFA achieved the highest reported internal power conversion efficiency of 70% with a double pass configuration     

60%电光效率高功率激光二极管阵列

设计并制备了980 nm高量子效率和极低光损耗的激光二极管(LD)外延材料和器件.微通道封装1 cm激光二极管阵列在连续(CW)工作条件下最大电光效率达到60.0%,相应的斜率效率和输出光功率分别为1.1W /A和38.2 W.测试得到外延材料的内损耗系数和内量子效率分别为0.58 cm-1和91.6%.测试分析表明,器件电光效率的提高主要在于新型的InGaAs/GaAsP应变补偿量子阱和大光腔结构设计.     

An asymmetric broad waveguide structure for a 0.98-μm high-conversion-efficiency diode laser

A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency（PCE）.The internal quantum efficiency,the series resistance,and the thermal resistance were theoretically optimized.The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers.The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs0.9P0.1/InGaAs quantum well.Experimentally,a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink,and a peak PCE of 60% is obtained at 26.3-W continuous wave output power.The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.     

高效率GaAsP/AlGaAs张应变量子阱激光二极管

从理论上设计优化了高效率808 nm GaAsP/AlGaAs张应变量子阱激光二极管外延材料的量子阱结构和波导结构参数,并采用低压金属有机气相外延技术实验制备了外延材料.将制作的芯片解理成不同腔长,测试得到外延材料的内损耗系数和内量子效率分别为0.82 cm-1和93.6 %.把腔长为900 μm的单巴条芯片封装在热传...     

1.06 μm high-power InGaAs/GaAsP quantum well lasers

The high power and low internal loss 1.06 μm InGaAs/GaAsP quantum well lasers with asymmetric waveguide structure were designed and fabricated. For a 4000 μm cavity length and 100 μm stripe width device, the maximum output power and conversion efficiency of the device are 7.13 W and 56.4%, respectively. The cavity length dependence of the threshold current density and conversion efficiency have been investigated theoretically and experimentally; the laser diode with 4000 μm cavity length shows better characteristics than that with 3000 and 4500 μm cavity length:the threshold current density is 132.5 A/cm², the slope efficiency of 1.00 W/A and the junction temperature of 15.62 K were achieved.     

An asymmetric broad waveguide structure for a 0.98-μm high-conversion-efficiency diode laser

A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency (PCE). The internal quantum efficiency, the series resistance, and the thermal resistance were theoretically optimized. The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers. The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs0.9P0.1/InGaAs quantum well. Experimentally, a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink, and a peak PCE of 60% is obtained at 26.3-W continuous wave output power. The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.     

1.06μm大功率连续半导体激光器

利用金属有机化学气相淀积(MOCVD)技术,生长了InGaAs/AlGaAs分别限制压应变双量子阱和单量子阱两种材料结构,通过对不同腔长单管激光器的LIV测试获得内部参数,对单、双阱两种材料结构器件参数进行对比分析,确定了单量子阱结构作为1.06μm大功率半导体激光器的材料结构。通过研究单管激光器的电光转换效率与腔长、注入电流的关系,获得了最高达到57.5%的电光转换效率。对1mm腔长单管激光器进行了大电流高温加速老化测试,结果显示研制出的单管激光器室温下在1.5A工作电流下寿命远大于104h。     

大功率及高转换效率2.1μm GaInSb/AlGaAsSb量子阱激光器

报道了激射波长为2.1 m 的GaInSb/AlGaAsSb双量子阱激光器。通过优化外延结构设计和欧姆接触,无镀膜的宽条激光器达到了9.8%的峰值功率转换效率,这比原来的值提高了1.5倍,室温下得到了615 mW的连续激射功率输出和1.5 W的脉冲激射功率输出。这些激光器的阈值电流密度低至126 A/cm2,斜率效率高达0.3 W/A。通过测试不同腔长的激光器,测得内损耗和内量子效率分别为6 cm-1和75.5%,均比原有器件有很大提升。激光器在连续工作3 000 h后,功率没有明显下降。     

高功率全固态准连续钛宝石激光器的实验研究

以激光二极管阵列(LDA)抽运Nd：YAG内腔倍频激光器作为抽运源,实现了全固态准连续钛宝石激光器的高功率、高效率运转。实验中,选择750～850nm宽带膜片组,钛宝石输出镜的透过率分别为T=5％、10％和15％。当532nm的抽运光为27W时,得到了6W输出功率及22．2％的转换效率。     

高功率、高效率、全固态准连续钛宝石激光器

以激光二极管阵列抽运Nd：YAG内腔倍频激光器作为抽运源，实现了全固态准连续钛宝石激光器的高功率、高效率运转。当532nm的抽运光为24W时，得到了4．7W输出功率及19．6％的高转换效率。为了获得钛宝石激光器理想的宽带输出，分别使用了两组膜片。第一组是750～850nm，第二组是850～950nm，每组膜片都有三种透过率，分别为5％，10％，15％。由于钛宝石荧光谱线的中心波长在795nm附近，使用第一组膜片在透过率为10％的情况下获得了最大4．7W的输出功率。使用第二组膜片也获得了3W左右的输出功率，为将要进行的宽带调谐提供了必要的前提。     

低温下运行的光纤耦合激光二极管抽运Tm,Ho∶YLF激光器

为了实现小型化、高功率、高效率连续2μm激光输出,采用中心波长792nm激光二极管(LD)抽运双掺杂Tm,Ho∶YLF晶体,将晶体封装在装有350mL液氮的杜瓦装置中,使其工作在77K温度条件下。光纤耦合激光二极管出纤功率14.8W,数值孔径0.3,芯径400μm。激光二极管端面抽运Tm,Ho∶YLF激光器,产生2.05μm线偏振连续激光输出,最大功率5.2W。由于Tm3+离子能级间的交叉弛豫效应导致的高抽运量子效率,实验获得的光-光转换效率为35%,斜度效率达到40%。采用双端面抽运结构,两个激光二极管注入功率29.6W时,Tm,Ho∶YLF激光器输出功率达10.2W,相当于光-光转换效率33%,斜度效率36%。     

多阳极220GHz倍频器单片设计

介绍了一款基于GaAs肖特基二极管单片工艺的220 GHz倍频器的设计过程以及测试结果。为提高输出功率,倍频器采用多阳极结构,8个二极管在波导呈镜像对称排列,形成平衡式倍频器结构。采用差异式结电容设计解决了多阳极结构端口散射参数不一致问题,提高了倍频器的转换效率和工作带宽。对设计的倍频器进行流片、装配和测试,测试结果显示：倍频器在204～234 GHz频率范围内,转化效率大于15%;226 GHz峰值频率下实现最大输出功率为90.5 mW,转换效率为22.6%。设计的220 GHz倍频器输出功率高,转化效率高,工作带宽大。     

多晶硅太阳电池背表面刻蚀提升其性能的产线工艺研究

对比研究了产线上多晶硅太阳电池背表面刻蚀对 其光电转换性能的影响。示范性实验结果表明:多晶硅太阳电池背表面刻蚀能够改善其短路 电流, 从而相应的光电转换效 率提升了约 0．1％。依据多晶硅太阳电池背表面刻蚀前后的扫描 电镜(SEM)形貌、背表面漫 反射光谱及完整电池片外量子效率的测试结果,改进的光电转换的原因可能源于背表面刻蚀 “镜面”化有利于太阳光子在背表面内反射和改进印刷Al浆与背表面覆盖接触。背表面刻蚀 与当前晶硅电池产线工艺兼容,能够提升电池片的光电转换效率,是一种可供选择的产线升 级工艺。     

2.0 W CW, diffraction-limited tapered amplifier with diode injection

The authors have demonstrated an all-semiconductor discrete-element 1.5 mm length tapered-amplifier MOPA (master oscillator power amplifier) emitting up to 2.0 W CW in a diffraction-limited pattern. The tapered single-pass amplifier MOPA exhibits a very high differential efficiency of 72% and a total energy conversion efficiency of 39% at 2.0 W CW output power. The high efficiency of the MOPA is attributed to the tapered amplifier design, which maximises extraction efficiency with a low-power injected beam of 25 mW from a single-mode laser diode. Such an MOPA will have applications where compact, high-efficiency, diffraction-limited sources of radiation are required, such as frequency doubling and free-space communication.<>     

High-power generation in IMPATT devices in the 100-200-GHz range

A silicon double-drift IMPATT diode with high uniform doping levels was simulated. Simulation results show that it is possible for silicon IMPATT diodes to generate extremely high pulsed output power for frequencies above 100 GHz under high current-density operation. The highest output power matched to a 1-Ω load resistance obtained at 150 GHz is 37.7 W with a DC current density of 200 kA/cm², although the calculated power conversion efficiency is low. It is also shown that the low-power conversion efficiency limits the diode's continuous wave power operation     

单级结构C+L波段掺铒光纤宽带光源

报道了利用双向抽运单级掺铒光纤结构研制的高效率C L波段放大自发辐射(ASE)宽带光源。实验表明,该结构在一定的掺铒光纤长度范围内,均可通过调节前后向抽运功率来获得带宽达80 nm(1525~1605 nm)光谱平坦的C L波段宽带光源。光源的抽运转换效率与掺铒光纤长度、前后向抽运功率分配有关。选择所需的最短掺铒光纤长度制作光源,既可以节省光纤,降低成本,还可以提高抽运转换效率。利用该光源结构获得了输出功率为13.5 dBm,抽运转换效率达23.2%的高效率C L波段放大自发辐射宽带光源。     

瓦级大功率白光LED光色电特性研究

文章基于瓦级大功率白光LED在照明领域应用的广泛性和重要性,展开了瓦级大功率白光LED光色电特性的研究。采用大功率LED封装设备与紫外-可见光-近紫外光谱分析系统,制备并测量了瓦级大功率白色发光二极管（LED）在不同正向电流IF驱动下的光通量、电功率、发光效率、发射光谱和色品坐标等参数。研究表明,光通量与电功率随耳的增大呈亚线性增长的趋势,而荧光粉转换效率下降是影响其辐射功率的主要原因之一。当电流增大时,白光LED光谱的蓝光峰值出现先蓝移后红移的现象,而黄光部分光谱形状无明显变化。此外,色坐标x、y值均随着IF的增大而降低,主波长减小,色温值升高。     

808nm高效率激光二极管

目前808nm高效率激光二极管产品的转换效率只有50%左右,还有很大的提升空间。通过提高欧姆接触层浓度、界面渐变和波导层掺杂等方面的外延材料结构优化,减小附加电压和电阻值,设计制作了808nm大光腔应变量子阱外延材料;并制作了200μm发光区标准单管,提取了材料内部参数,材料内损耗iα为0.67cm-1,内量子效率iη为0.88;将圆片解理成2mm腔长的巴条进行腔面镀膜,并烧结成标准单管,25℃下单管电光效率达到61.1%;将巴条烧结到微通道载体上,制作成标准微通道水冷单条阵列,水温15℃110A下输出光功率126.6W,电光转换效率62.77%。     

准连续Ti~(3+):Al_2O_3可调谐激光的研究

本文给出了Ti~(3+):Al_2O_3的准连续可调谐激光的实验结果。采用Nd:YAG内腔倍频532nm的准连续输出作为泵浦源,得到Ti~(3+):Al_2O_3的连续可调谐输出。波长覆盖范围为685nm到821nm。最大输出功率为293mW,斜率效率为20％,在805nm处的窄谱输出功率达240mW,总体转换效举为26％。