Very-low-threshold current density continuous-wave quantum-dot laser diode

Data are presented showing that a quantum-dot laser diode can achieve a continuous-wave room-temperature threshold current density as low as 11.7 A/cm². The broad-area laser diode operates at a wavelength of 1.22 mum and delivers a power level of 0.42 W with 40% maximum slope efficiency in p-up mounting without heatsinking. Spectral measurements indicate the onset of stimulated emission at ~6 A/cm².     

光纤激光阵列自组织相干合成的性能研究

研究了基于倏逝波耦合的自组织相干合成激光阵列。应用静态本征模/超模理论推导阵列模式;通过数值方法考察阵列激光系统的动态特性进而分析输出功率的稳定性、阵列的扩展能力和阵列模式;并对两种方法得到的阵列模式进行了比较分析。结果表明:输出功率的稳定性以及输出功率的大小受阵列的锁相性能和阵元间的相位差影响;随着激光单元数目的增加,阵列总输出功率会非线性增大。通过跟踪各个阵元的相位变化并考察阵列模式的近场和远场特性,初步验证了37单元阵列的相干合成,随着阵元数目的增加,中心阵元与其邻近层阵元的振幅差会逐渐减小。     

High-efficiency continuous-wave Raman laser pumped by an injection-locked broad-area diode laser

We report an efficient CW far-off-resonance Raman laser in H/sub 2/ gas pumped by an injection-locked broad-area diode laser. The pump wavelength 794 nm is Raman shifted to the Stokes wavelength 1185 nm. The total output Stokes power reaches 21.6/spl plusmn/0.5 mW and the photon conversion efficiency reaches (74/spl plusmn/10)%.     

Ridge-width dependence on high-temperature continuous-wave quantum-cascade laser operation

We report continuous-wave (CW) operation of quantum-cascade lasers (/spl lambda/=6 /spl mu/m) up to a temperature of 313 K (40/spl deg/C). The maximum CW optical output powers range from 212 mW at 288 K to 22 mW at 313 K and are achieved with threshold current densities of 2.21 and 3.11 kA/cm/sup 2/, respectively, for a high-reflectivity-coated 12-/spl mu/m-wide and 2-mm-long laser. At room temperature (298 K), the power output is 145 mW at 0.87 A, corresponding to a power conversion efficiency of 1.68%. The maximum CW operating temperature of double-channel ridge waveguide lasers mounted epilayer-up on copper heatsinks is analyzed in terms of the ridge width, which is varied between 12 and 40 /spl mu/m. A clear trend of improved performance is observed as the ridge narrows.     

1.63kW单纤单振单模连续全光纤激光器

报道了一种单纤单振单模连续全光纤激光器,工作波长为1 080nm,输出功率可达1.63kW。激光器使用7个输出功率为300 W、工作波长为976nm的半导体激光器(LDs)充当泵浦源,并利用短腔长结构成功地抑制了受激拉曼散射(SRS)。测试结果显示,所获得激光的光谱信噪比(SNR)大于40dB,1h内的功率不稳定度小于1%,光-光转换效率约为75.46%。此外,通过对光纤盘绕的合理设计,有效地抑制了光纤中的高阶模式,在满功率输出时成功地获得了单模激光(M2<1.1)。     

Low-threshold continuous-wave two-stack quantum-dot laser withreduced temperature sensitivity

Data are presented on continuous wave operation of two-stack quantum dot lasers designed with reduced temperature sensitivity in their threshold. The InAs quantum dots are designed to have a wide energy spacing (~102 meV) between the ground and first excited radiative transitions. Selectively oxidized stripe lasers have continuous wave threshold currents as low as 1.2 mA for 2 μm wide stripes and minimum threshold current densities of 26 A/cm² for 13-μ-m wide stripes. Broad area lasers have continuous wave threshold current densities as low as 40 A/cm², even for p-up mounting. Ground state lasing is obtained up to the highest temperature measured of 326 K     

连续腔内倍频拉曼激光器的归一化理论解析

腔内倍频拉曼激光器是获得黄光激光光源的重要途径,目前尚未有直接的表达式描述连续腔内倍频激光器的功率输出对抽运和激光器参数的赖关系。以速率方程为基础,对腔内倍频连续拉曼激光器的理论模型进行归一化处理,得到平面波近似下连续腔内倍频拉曼激光器的归一化速率方程组。对此方程组进行求解,得到描述激光器输出的表达式各变量以及参量与输出变量之间的归一化表达式,根据表达式获得了描述激光器运行的理论曲线。     

500 W continuous-wave fibre laser with excellent beam quality

Power scaling of continuous-wave fibre lasers with up to 0.5 kW output powers from a single fibre with nearly diffraction-limited beam quality without the limitation of nonlinear effects is reported.     

A simplified tunable frequency interval optical frequency comb generator using a single continuous-wave laser

We propose and demonstrate a simplified and tunable frequency interval optical frequency comb (OFC) generator based on a dual-drive Mach-Zehnder modulator (DD-MZM) using a single continuous-wave (CW) laser and low-power radio frequency (RF) driven signal. A mathematical model for the scheme is established. The 21- and 29-mode OFCs with frequency interval ranging from 6 GHz to 40 GHz are obtained under DD-MZM driven by a low-power RF signal within a maximum bandwidth of 1.12 THz. The generated OFCs exhibit spectral flatnesses of less than 0.5 dB and 0.8 dB within bandwidths of 160 GHz and 400 GHz, respectively.     

On-wafer continuous-wave operation of InGaN/GaN violet laser diodes

Continuous-wave operation of etched-facet InGaN/GaN multiquantum-well ridge-waveguide laser diodes grown by low pressure MOVPE on a sapphire substrate has been achieved on-wafer for >2 min at 15% above threshold. The threshold current density and voltage were 9.1 kA/cm² and 7.6 V, respectively, at 15°C, and the lasing wavelength was 400.6 nm     

Semiconductor laser pumping of continuous-wave Pr/sup 3+/-doped ZBLAN fibre laser

Blue semiconductor laser pumped continuous-wave laser oscillation of a Pr-doped ZrF/sub 4/-BaF/sub 2/-LaF/sub 3/-AlF/sub 3/-NaF fibre in the red spectral range is reported for the first time. The pump power is provided by a frequency-doubled optically pumped semiconductor laser system. When pumped with 300 mW at a wavelength of 479.7 nm, the Pr/sup 3+/-laser emitted 94 mW of output power at a wavelength of 635 nm. Threshold pump power and slope efficiency with respect to the incident pump power were determined to be 49.7 mW and 41.5%, respectively.     

单频连续波金刚石拉曼激光器研究进展（特邀）

受激拉曼散射增益具有无空间烧孔特性,通过简单的腔型设计,拉曼激光器即可实现稳定单纵模运转。同时拉曼激光波长灵活,因此拉曼激光器在特殊波长单频激光领域具有重要技术优势。近年来,随着金刚石合成技术的突破,以金刚石作为增益介质的单纵模、高功率拉曼激光器获得了快速发展。文中简要介绍了拉曼激光器的单纵模运行机制;总结了单纵模金刚石拉曼激光器的研究进展;并对单纵模金刚石拉曼激光器的发展趋势进行了展望。     

利用可调谐激光器产生可调谐的连续波光载信号

针对采用传统的电子器件的调频/连续波(FM/CW) 产生方法由于带宽限制无法达到较高分辨率的问题,提出一种基于增益开关可调谐半导体激 光器(TLD)产生高频FM/CW信号的方案,具有中心 频率和波长双重可调谐性、结构简单和易于扩展的特点与优势。本文方案可用于基于光纤无 线电(ROF,radio-over-fiber)技术 的多雷达头分布系统,可方便实现多通道切换。实验中,通过2GHz的调制信号,实现了10倍频20GHz的信号产生以及中心频率为10GHz 、带宽为500MHz的调频连续波信号产生。     

Fabrication of room temperature continuous-wave operation GaN-based ultraviolet laser diodes

Two kinds of continuous-wave GaN-based ultraviolet laser diodes (LDs) operated at room temperature and with different emission wavelengths are demonstrated.The LDs epitaxial layers are grown on GaN substrate by metalorganic chemical vapor deposition,with a 10×600 μm2 ridge waveguide structure.The electrical and optical characteristics of the ultraviolet LDs are investigated under direct-current injection at room temperature. The stimulated emission peak wavelength of first LD is 392.9 nm,the threshold current density and voltage is 1.5 kA/cm² and 5.0 V,respectively.The output light power is 80 mW under the 4.0 kA/cm² injection current density. The stimulated emission peak wavelength of second LD is 381.9 nm,the threshold current density the voltage is 2.8 kA/cm² and 5.5 V,respectively.The output light power is 14 mW under a 4.0 kA/cm² injection current density.     

Passive mode locking of an energy transfer continuous-wave dye laser

The first passive mode locking of a continuous-wave energy transfer dye laser is reported. Using an argon ion laser-pumped mixture of rhodamine 6G and sulphur rhodamine 101 as the active medium, pulses of less than 500 fs duration have been generated over the spectral range 652-694 nm using two different saturable absorbers in a simple linear cavity without dispersion optimization. Pulses as short as 120 fs have been measured using standard second-harmonic generation autocorrelation techniques.     

Ytterbium-doped large-core fibre laser with 1 kW of continuous-wave output power

A ytterbium-doped fibre laser with up to 1 kW of continuous-wave output power at 1.09 /spl mu/m with a slope efficiency of 80% and a good beam quality (M/sup 2/=3.4) is reported. The fibre was pumped by two diode-stack sources launched through opposite ends. No undesirable roll-over was observed in output power with increasing pump power.     

>700W continuous-wave output power from single laser diode bar

>700 W continuous-wave output power has been demonstrated from a single 1 cm-wide laser bar (~940 nm) with 77% fill factor. Maximum power conversion efficiency (PCE) of 65% has been achieved. Facet power density of 170 mW/mum and maximum PCE of 69% have been measured for 10% fill-factor bars with 3 mm cavity length     

Room-temperature continuous-wave 1.55 /spl mu/m GaInNAsSb laser on GaAs

The first low-threshold 1.55 /spl mu/m lasers grown on GaAs are reported. Lasing at 1.55 /spl mu/m was observed from a 20/spl times/2400 /spl mu/m as-cleaved device with a room-temperature continuous-wave threshold current density of 579 A/cm/sup 2/, external efficiency of 41%, and 130 mW peak output power. The pulsed threshold current density was 550 A/cm/sup 2/ with >600 mW peak output power.     

全固态复合内腔和频554.9nm连续波黄-绿光激光器

报道了全固态连续波554.9 nm黄-绿光激光器,黄-绿激光是分别由Nd∶YAG和Nd∶YVO4晶体的1342 nm和946 nm谱线非线性和频产生,两条谱线在各自晶体对应能级跃迁分别为4F3/2-4I11/2和4F3/2-4I9/2。实验中采用复合腔结构,利用KTP晶体II类临界相位进行内腔和频,当注入到Nd∶YAG和Nd∶YVO4晶体的泵浦功率分别为20 W和10 W时,获得1.1 W的TEM00连续波554.9 nm黄-绿激光输出。4h功率稳定度优于±2.8％。