垂直腔面发射激光器

The development and application of vertical-cavity surface-emitting lasers (VCSELs) are summarized in this paper. The emphasis is focused on the high power single and 2-D arrays bottom-emitting VCSELs with a wavelength of 980nm. A distinguished device performance is achieved. The maximum continuous-wave (CW) output power of large aperture single devices with active diameters up to 500μm is as high as 1.95W at room temperature, which is to our knowledge the highest value reported for a single device. Size dependence of the output power, the threshold current and the differential resistance are discussed. A 16 elements array with 200μm aperture size (250μm center spacing) of individual elements shows a CW output power of 1.32W at room temperature.     

218 W quasi-CW operation of 1.83 μm two-dimensional laser diodearray

218 W quasi-CW output power has been measured from a 1.83 μm InGaAsP/InP 90 element rack and stack configuration array. Despite strong dependence of the device efficiency on temperature, a CW output power of 54 W has been obtained. The maximum efficiency for CW operation was 18% for 30 W CW output power     

400MHz,CW 300W VDMOS功率场效应晶体管

采用 Mo栅工艺技术降低栅串联电阻 ,通过优化工艺参数 ,全离子注入工艺 ,研制出了在 40 0 MHz下共源推挽结构连续波输出 30 0 W的高性能 VDMOSFET,其漏极效率大于 5 0 % ,增益大于 9d B。     

High-brightness, high-efficiency, single-quantum-well laser diode array

Single-quantum-well, separate-confinement double-heterostructure laser diode arrays which exhibit a high power conversion efficiency of greater than 54% have been demonstrated. The high efficiency results from a low internal loss of 3cm1 and high internal conversion efficiency. The maximum output power for a 100?m emitting aperture is 2 W CW and is independent of the cavity length.     

高功率窄脉冲垂直腔面发射激光器n-DBR反射率的优化

从理论上研究了n型分布布拉格反射镜(n-DBR)的反射率对器件阈值电流、输出功率以及转换效率的影响,得出了最佳反射率。在此基础上研制了垂直腔面反射激光器(VCSEL)单管和阵列器件,采用波形分析法对VCSEL器件的功率进行了测试。在脉冲宽度60ns,重复频率100Hz条件下,500μm口径单管器件在注入电流为110A时,峰值输出功率达102W,功率密度为52kW/cm2,4×4、5×5阵列器件在100A时,功率分别达到98W和103W。对比了单管器件在连续、准连续和脉冲工作条件下的输出特性和光谱特性,连续和准连续条件下激射波长的红移速率分别为0.92nm/A和0.3nm/A,6A时的内部温升分别为85℃和18℃,而脉冲条件下激射波长的红移速率仅为0.0167nm/A,6A时的温升为1.5℃,远小于连续和准连续的情况,这也是器件在脉冲条件下能得到很高输出功率的主要原因。     

Efficient upconversion pumping at 1.064 mu m Tm/sup 3+/-doped fluoride fibre laser operating around 1.47 mu m

1.064 mu m upconversion pumping was used to operate a highly efficient CW and Q-switched thulium (Tm/sup 3+/)-doped fluoride fibre laser at around 1.47 mu m. The maximum CW output power was 100 mW for a launched pump power of 570 mW. The threshold power was 200 mW, the slope efficiency 27% and the wavelength width 20 nm. A peak power of 70 W was generated for Q-switching at a launched pump power of 300 mW.<>     

RF-pumped infrared laser using transverse gas flow

A transverse gas flow configuration has been developed utilizing RF discharge waveguide technology for several infrared lasers. Two potential applications have been identified: pulsed chemical laser and CW CO2laser. In the 3.8 μm DF laser, the flowing gas device provides rapid gas replenishment to maintain high electrical efficiency at high repetition rates. An average power of 0.6 W was achieved at 1 kHz. An order of magnitude power improvement can potentially be developed in a closed cycle system. In the CW CO2laser, the flowing gas provides efficient cooling so that high output power per unit gain length can be achieved. A 16 W output in a 20 cm gain length device, corresponding to a record 0.8 W/cm output has been demonstrated. This system can be developed into a 20-60 W laser with a 20-50 cm gain length.     

Optimized All-Fiber Supercontinuum Source at 1.3 μm Generated in a Stepwise Dispersion-Decreasing-Fiber Arrangement

In this paper, the generation of a continuous-wave (CW)-pumped supercontinuum (SC) source at 1.3 mum is described. The device makes use of a tunable Yb-doped fiber laser, a cascade of fiber Bragg grating mirrors, and a concatenation of standard silica fibers with stepwise decreasing dispersion. It is shown that the dispersion-decreasing-fiber set enhances the width of the generated SC, since it favors the fission of the CW input into high-order solitons. The generated SC spans from 1280 to 1513 nm, shows an average output power of 1.34 W, and exhibits >0-dBm/nm spectral density of over 200 nm.     

High-Performance Continuous-Wave Operation of $lambda sim {hbox {4.6}}~mu{hbox {m}}$ Quantum-Cascade Lasers Above Room Temperature

We report the high-performance continuous-wave (CW) operation of 10-mum-wide quantum-cascade lasers (QCLs) emitting at lambda ~ 4.6mum, based on the GaInAs-AlInAs material without regrowth, in epilayer-up and -down bonding configurations. The operational characteristics of QCLs such as the maximum average power, peak output power, CW output power, and maximum CW operating temperature are investigated, depending on cavity length. Also, important device parameters, i.e., the waveguide loss, the transparency current density, the modal gain, and the internal quantum efficiency, are calculated from length-dependent results. For a high-reflectivity (HR) coated 4-mm-long cavity with epilayer-up bonding, the highest maximum average output power of 633 mW is measured at 65% duty cycle, with 469 mW still observed at 100%. The laser exhibits the maximum wall-plug efficiencies of 8.6% and 3.1% at 298 K, in pulsed and CW operatons, respectively. From 298 to 393 K, the temperature dependent threshold current density in pulsed operation shows a high characteristic temperature of 200 K. The use of an epilayer-down bonding further improves the device performance. A CW output power of 685 mW at 288 K is achieved for the 4-mm-long cavity. At 298 K, the output power of 590 mW, threshold current density of 1.52 kA/cm², and maximum wall-plug efficiency of 3.73% are obtained under CW mode, operating up to 363 K (90degC). For HR coated 3-mm-long cavities, laser characteristics across the same processed wafer show a good uniformity across the area of 21 cm², giving similar output powers, threshold current densities, and emission wavelengths. The CW beam full-width at half-maximum of far-field patterns are 25deg and 46deg for the parallel and the perpendicular directions, respectively.     

High power, 8.5 W CW, visible laser diodes

Visible laser diodes have been fabricated from AlGaInP operating at approximately 680 nm to high output powers. Broad area lasers with 100 mu m wide emitting apertures operate to greater than 1 W CW with a different efficiency of 38%. The threshold current densities of the material have been measured to be as low as 350 A/cm/sup 2/ for lasers with 30% mirror reflectivities. Monolithic bars 8 mm long with 50 mu m emitting apertures periodically spaced on 500 mu m centres have been fabricated which operate to 8.5 W CW.<>     

Power, efficiency, and thermal characteristics of type-II interbandcascade lasers

High-performance mid-infrared type-II interband cascade lasers have been demonstrated under continuous-wave (CW) conditions with record-high wall-plug efficiencies (>14%) and output powers (>100 mW/facet) above 77 K. Device characteristics of these type-II interband cascade lasers are investigated systematically in terms of their output powers and efficiencies. Also, by comparing the temperature dependence of the threshold currents under pulsed and CW conditions, the thermal resistance and maximum heat sink temperature for CW operation are estimated for several mesa sizes. The limiting factors due to device heating for high-power/high-efficiency operation are identified and discussed in connection with device dimensions and packaging for the purpose of assessing further improvements     

Vertical external-cavity surface-emitting laser for dual-wavelength generation

We report an optically pumped vertical external-cavity surface-emitting laser that is designed for emission at two wavelengths simultaneously. Single transverse mode continuous-wave (CW) operation is demonstrated at the wavelengths of 984 and 1042 nm. The device produces a CW optical power of 140 mW for the 984-nm component and 115 mW for the 1042-nm component, exhibiting over 10% efficiency. At a high pump power, self-pulsation of the components appeared on top of the CW-mode components. The maximum total output of 1 W was obtained at the pump power of 9 W.     

具有线性GRIN结构GaAs/AlGaAs单量子阱激光器

采用ＭＯＣＶＤ 方法成功地研制了具有线性ＧＲＩＮ 结构ＧａＡｓ／ＡｌＧａＡｓ单量子阱激光器。该激光器的峰值波长为８１５～８２５ ｎｍ ,阈值电流为１３０ ｍ Ａ。工作电流在４８０ ｍ Ａ 时,单面连续输出光功率高达２００ ｍ Ｗ,且基本保持在单模工作状态。工作在９７０ ｍ Ａ 时,单面连续输出光功率为０．５ Ｗ。     

High-power etched-facet lasers

We demonstrate, for the first time, laser diodes with anetched facet fabricated by chemically assisted ion beametching, producing 1?7 W pulsed and 470mW CW output power from one facet. The devices were coated and bonded junction-side-up and tested at room temperature. The single 40 ?m stripe, 300 ?m-long devices exhibit 94 mA threshold current and differential quantum efficiencies of 80% pulsed (78% CW).     

530～650MHz 20W CW Si-VDMOS场效应晶体管

报道了530~650MHz 20W连续波Si-VDMOS场效应晶体管的研制结果。该器件采用polySi/WN/Au的多层复合栅技术降低栅串联电阻,采用栅下场氧化垫高技术降低反馈电容,采用穿通型硅外延材料优化导通电阻提高器件工作效率,全离子注入自对准工艺等技术,在上述频带内,连续波,28V工作电压下,静态电流50mA,该器件输出功率达20W,效率达49%,增益大于7.5dB。     

端面抽运高功率连续单频1064 nm Nd:YVO4环行腔激光器

采用808 nm光纤耦合输出激光二极管(FCLD)单端端面抽运Nd∶YVO4晶体,采用四镜折叠环行腔,在腔内插入法拉第旋光器和半波片实现激光的单向运转以抑制空间烧孔效应,并在腔内加入标准具,最终实现连续单频1064 nm激光输出.在24.6 W抽运功率时,最高输出功率达到9 W,光-光转换效率为36.6%,M2因子约为1.14,频率漂移约200 MHz.     

Pulsed characterisation of GaN HEMTs on Si (1 1 1) substrate

The DC and RF power characteristics of GaN HEMTs under continuous wave (CW) and pulsed load-pull measurement are examined, in this article. The results give a comprehensive understanding of self-heating effects and allow improved heat dissipation, by pulsed measurement. The measured output power increases under the pulse load-pull measurement, due to the isothermal environment. The RF power performance for pulsed mode was measured at 3.5?GHz, with 18.4?dB power gain and a large 3.5?W/mm power output, under pulse load-pull, which is a 3.25?dB improvement, compared to CW operation. The relationship of output power and impedance is determined by load-pull measurement.     

53% wallplug efficiency 975nm distributed feedback broad area laser

100 mum-stripe, 2 mm-long, DFB diode lasers with narrow spectral widths of 2.3 Aring FWHM were achieved at a CW power of 5 W. The centre wavelength was locked at the Bragg condition and shifts at a rate of 0.065 nm K^-1. 1 mm-long DFB laser showed a record high 53% wallplug efficiency for grating-stabilised semiconductor lasers at 25degC heatsink temperature and 2 W CW output power     

High-performance 980 nm quantum dot lasers for high-powerapplications

High-performance quantum dot lasers emitting at 980 nm with output powers of up to 4 W CW from a single facet (AR/HR coating, 100 μm stripe width) have been fabricated. Wall-plug efficiencies >50%, were achieved at room temperature. Owing to an improved carrier confinement output powers as high as 1 W CW can be obtained from the fundamental dot transition even at temperatures as high as 110°C     

单透镜望远镜腔型连续锁模倍频Nd:YAG飞秒激光泵浦源

本文着重介绍了具有单透镜望远镜腔的CW(连续)锁模倍频Nd∶YAG飞秒激光泵浦源的腔型设计和动态稳定性能实验研究。在单灯3.5kW连续激励下,获得了脉宽约100ps,平均功率约1.7W的CW锁模倍频绿光输出,其稳定度优于3％。