高功率横向激励CO2波导激光器

我们描述了高功率和高效率横向激励的CO2波导激光器的进展。用20厘米长的波导，在20微秒期间，器件提供175瓦的输出脉冲，效率达3.7%或平均功率20瓦，其效率为3.1%。这个输出功率接近以前从横向激励CO2波导激光器所得到的功率的五倍。通过预电离小心控制电场与压强比得到这个进展。     

金属波导连续光泵气体太赫兹激光器

针对紧凑型光泵气体太赫兹激光器(OPTL)技术,设计并研制了全金属波导结构的气体太赫兹(THz)激光器原理样机.THz激光器工作介质为CH_3OH气体,最佳工作气压30 Pa,在波长9.69μm、连续功率44 W的9P(36)支CO_2激光泵浦下,实验测得在2.52 THz频点输出功率150 m W,光子转换效率为8.4%.研究THz激光输出功率与CH_3OH工作气压、泵浦光功率的关系、以及THz激光输出稳定性,并通过压电陶瓷对THz激光腔长进行精密调节,同时测量输出功率的变化情况,讨论了金属波导THz激光器的纵模特性.实验工作与结果为下一步紧凑型折叠波导腔全金属OPTL的研制提供了参考.     

小型玻璃波导使气体激光器微型化

贝耳实验室的史密斯(P. Smith)用空心玻璃波导——内径约为铅笔芯厚度的一半的小管——完成气体激光器微型化。典型的波导气体激光器长约2吋,直径为百分之二吋。这种激光器将来总有一天能用于使用相干光携带大量话音、图片和数据信号的通讯系统中。     

连续的DCN波导激光器

本文介绍了连续DCN波导激光器。激光管由直径4.8厘米、长2.5米的石英管组成,其输出波长为195微米和190微米,最大输出功率为30毫瓦左右。同时给出实验研究结果以及输出功率与其他参数之间的关系。     

LP-MOVPE生长宽波导有源区无铝单量子阱激光器

介绍了无铝激光器的优点,利用LP-MOVPE生长出宽波导有源区无铝SCH-SQW结构激光器.该结构采用宽带隙InGaAlP作限制层,加宽的InGaP作波导层,增加对载流子和光子的限制作用,以克服有铝激光器易氧化和全无铝激光器载流子易泄漏的缺点.制作的条宽100μm、腔长1mm的激光器(腔面未镀膜),激射波长为831nm,室温连续输出光功率达1W.     

1.1瓦密封波导CO激光器

过去几年中,密封波导CO激光器的输出功率一直在升高。休斯研究实验室的Charles Κ. Asawa在应用物理通讯(1974,24,No 121)上报道了这种激光器的连续波输出为1.1瓦,效率为5.7%,连续工作二小时不发生输出变坏。这些实验中使用的BeO激光管长14厘米,内径为2毫米,冷却到210 K。观察到了跃迁从一组谱线向另一组谱线移动时输出的缓慢变化。据信,这些温度变化是由于甲醇干冰糟中的移动。     

200K高特征温度的1.3μm AlInGaAs应变单量子阱激光器

在20～80℃范围内连续工作条件下,非对称波导层结构的1.3μm AlInGaAs/AlInAs单量子阱激光器的特征温度为200K,这是目前国内报道的相同有源材料、相同发射波长的激光器中最高的特征温度值.因此AlInGaAs是长波长光纤激光器的理想有源区材料.研究表明非对称波导结构能降低光吸收,提高激光器的高温特性和COD阈值.     

LP-MOVPE生长宽波导有源区无铝单量子阱激光器

介绍了无铝激光器的优点 ,利用 L P- MOVPE生长出宽波导有源区无铝 SCH- SQW结构激光器 .该结构采用宽带隙 In Ga Al P作限制层 ,加宽的 In Ga P作波导层 ,增加对载流子和光子的限制作用 ,以克服有铝激光器易氧化和全无铝激光器载流子易泄漏的缺点 .制作的条宽 10 0 μm、腔长 1mm的激光器 (腔面未镀膜 ) ,激射波长为831nm,室温连续输出光功率达 1W.     

GaAs薄膜波导

最近上海光机所半导体组研制成了一种GaAs薄膜波导.他们采用气相外延方法,在(100)取向、掺杂为～10~(18)厘米~(-3)的n-GaAs衬底上,生长一层浓度为10~(14)～10~(15)厘米~(-3)、厚度为10～20微米的GaAs薄膜,用图1所示的系统观察到了导光现象,并估计了波导损耗及波导出射的光强空间分布.     

LD端面抽运Nd:MgO:LiNbO3质子交换波导激光器

报道了 Nd:Mg O:L i Nb O3 波导激光器的研制。在掺有 Nd和 Mg O的 x切 Li Nb O3 晶片上利用退火质子交换法制作单模光波导 ,用波长为 0 .814μm的半导体激光器作为抽运源 ,以波导两端面本身作为反射镜 ,研制成了波导激光器 ,获得波长为 1.0 84 μm的激光输出 ,其阈值功率为 3.5m W,斜率效率为 16 % ,最大输出功率为 1.2 m W。     

InP-based passive ring-resonator-coupled lasers

The design of passive ring-coupled lasers based on InGaAsP waveguides is investigated using a beam propagation method. Mode coupling, propagation loss due to bending, and scattering loss from waveguide sidewall roughness are taken into account. By compromising threshold gain, linewidth and side-mode suppression ratio (SMSR), suitable waveguide width and coupling strength are determined for different ring sizes. Using a ring with radius ranging from 20 to 200 /spl mu/m, it is possible to design passive ring-coupled lasers with threshold gain less than 60/cm and 80/cm for waveguide sidewall roughness 5 and 10 nm, respectively, SMSR larger than 50 dB, and linewidth in the range of /spl sim/3-500 kHz.     

Characteristics of sealed-off waveguide CO2lasers

Gain and output power of sealed-off waveguide CO2lasers are presented as a function of gas mixtures and total gas pressure. Experimental data on circular-bore and square-channel waveguide lasers are presented. Output power per unit length of 0.2 W/cm is achieved for both types of lasers in agreement with gas-discharge scaling laws which are presented. Saturation intensities as high as 24 kW/cm²are inferred from the data. The effects of the optical properties of the waveguide wall material on the waveguide losses are discussed and theoretical waveguide loss versus wavelength is presented for BeO, Al2O3, and fused silica.     

Room-temperature 2.81-/spl mu/m continuous-wave operation of GaInAsSb-AlGaAsSb laser

GaInAsSb-AlGaAsSb multiple quantum-well (QW) lasers with an emission wavelength of 2.81 /spl mu/m are reported. The ridge waveguide lasers with highly strained QWs show continuous-wave laser emission up to 25/spl deg/C; in pulsed mode, the lasers operate up to 60/spl deg/C. For pulsed operation, a threshold current density of 360 A/cm/sup 2/ is found for devices with 30-/spl mu/m stripe width and 2-mm cavity length at room temperature. A low threshold current density at infinite length of 248 A/cm/sup 2/ is derived.     

Compact solid-state waveguide lasers

Glass waveguide lasers will fill an important niche as optical sources in communication, RF photonics, and optical metrology. This is primarily because waveguide lasers benefit from compact size, low noise, relatively high output powers, long upper-state lifetimes, and simple integration with optical-fiber-based systems. Although we do not expect waveguide lasers and amplifiers to ever supplant fiber and semiconductor lasers and amplifiers in every possible communications application, waveguide lasers have a number of advantages over traditional lasers for these uses. Single-frequency waveguide lasers provide narrow linewidth and high output power in a compact, monolithic package. The narrow linewidth is an important advantage over standard semiconductor lasers, and the compact size makes single-frequency waveguide lasers better suited than fiber lasers or extended-cavity semiconductor lasers for many applications.     

InAs/AlSb quantum cascade lasers operating at 6.7 /spl mu/m

Quantum cascade lasers based on the InAs/AlSb material system have been realised. The optical confinement is obtained using a plasmon waveguide with n/sup +/-InAs cladding layers. In pulse mode the lasers emit close to 6.7 /spl mu/m with a threshold current density of 5 kA/cm/sup 2/ at 90 K. The maximum operating temperature is 220 K.     

Room-temperature continuous-wave quantum cascade lasers grown by MOCVD without lateral regrowth

We report on room-temperature continuous-wave (CW) operation of /spl lambda//spl sim/8.2 /spl mu/m quantum cascade lasers grown by metal-organic chemical vapor deposition without lateral regrowth. The lasers have been processed as double-channel ridge waveguides with thick electroplated gold. CW output power of 5.3 mW is measured at 300 K with a threshold current density of 2.63 kA/cm/sup 2/. The measured gain at room temperature is close to the theoretical design, which enables the lasers to overcome the relatively high waveguide loss.     

InGaN multiple quantum well laser diodes grown by molecular beam epitaxy

The first InGaN multiple quantum well laser diodes produced by molecular beam epitaxy are reported. Ridge waveguide lasers have been demonstrated at room temperature under pulsed current injection conditions. The lasers emit at a wavelength of approximately 400 nm with a spectral line-width of less than 0.2 nm, and a threshold current density of /spl sim/30 kA cm/sup -2/.     

Integrated external-cavity InGaAs/InP lasers using cap-annealing disordering

InGaAs/InP multiple-quantum-well lasers were integrated with low-loss waveguides in the long-wavelength region using a cap-annealing disordering technique which does not require a regrowth process. The coupling efficiency between them does not increase the threshold current of the lasers. The optical loss in the waveguide was 7.8 cm/sup -1/ and was due to free-carrier absorption in the cladding layers.<>     

Single quantum well strained InGaAs/GaAs lasers with large modulation bandwidth and lower damping

Strained In/sub 0.2/Ga/sub 0.8/As/GaAs single quantum well polyimide buried ridge waveguide lasers with 3 dB modulation bandwidths of 15 GHz and gain compression factors in as small as 9.98*10/sup -18/cm/sup -3/ have been fabricated. The authors have also observed that the gain compression factor is not larger than in lasers with bulk active areas, and is lower for structures with a smaller number of wells and shorter cavity lengths.<>     

Continuous-wave operation of GaInAsSb-GaSb type-II ridge waveguide lasers emitting at 2.8 /spl mu/m

We have realized compressively strained GaInAsSb-GaSb type-II double quantum-well lasers with an emission wavelength of 2.8 /spl mu/m. Using broad area devices, an internal absorption of 9.8 cm/sup -1/ and an internal quantum efficiency of 0.57 is determined. For the increase of the threshold current with temperature, a T/sub 0/ of 44 K is obtained. Narrow ridge waveguide lasers show continuous-wave laser operation at temperatures up to 45 /spl deg/C, with room-temperature (RT) threshold current of 37 mA. At RT, the maximum optical output power per facet of an uncoated 800/spl times/7 /spl mu/m/sup 2/ ridge waveguide laser exceeds 8 mW.