High-power and highly reliable 1020-nm ridge waveguide laser diodes with small aspect ratio as a pumping source for praseodymium-doped fiber amplifiers

The structure of an asymmetrically expanded optical field normal to the active layer was applied to 1020-nm ridge waveguide laser diodes in order to increase their maximum kink-free output power and reduce the aspect ratio of the output beams. As a result, a kink-free output power of more than 400 mW and an aspect ratio of less than 2.5 were achieved by this structure. Good reliability was also obtained at an output power of 300 mW at 50/spl deg/C.     

980nm InGaAs应变量子阱激光器及组合件

利用分子束外延技术研制出了高质量InGsAs/GaAs应变量子阱材料及量子阱激光器.脊形波导窄条形量子阱激光器的阈值电流和微分量子效率分别为15mA和0.8 W/A,线性输出功率大于150mW,基横模输出功率可达100mW.InGaAs应变量子阱激光器和单模光纤进行了耦合,其组合件出纤光功率典型值为40mW,最大值可达60mW.显示出了高的基横模输出功率和高的耦合效率.其组合件在40～60mW下,中心发射波长在977nm.满足了对掺铒光纤高效率泵浦的波长要求,成功地研制出适于掺铒光纤放大器用的应变量子阱激光器.     

A high-power tapered and cascaded active multimode interferometer semiconductor laser diode

A high power semiconductor laser diode with a tapered and cascaded active multimode interferometer (MMI) cavity was designed and demonstrated.An output power as high as 32 mW was obtained for the novel laser diode with a tapered and cascaded active MMI cavity,being much higher than the 9.8 mW output power of the conventional single ridge F-P laser with the same material structure and the same device length due to the larger active area;and also being higher than the 21.2 mW output power of the rectangular and cascaded active MMI laser diode with nearly the same structure,except for the shape of the MMI area.In addition,the tapered and cascaded active multimode interferometer laser showed stable single mode outputs up to the maximum output power.     

小垂直发散角大光腔980nm单模InGaAs/GaAs/AlGaAs量子阱激光器

通过采用经过优化的新型大光腔结构,脊形波导980nm单模InGaAs/GaAs/AlGaAs多量子阱半导体激光器在保持大功率光输出的同时获得了较小的垂直发散角.结果表明波导中的光功率密度可以降低,获得了大于400mW、斜率效率0.89W/A的输出光功率,垂直方向远场发散角也降低到23°.     

小垂直发散角大光腔980nm单模InGaAs/GaAs/AlGaAs量子阱激光器

通过采用经过优化的新型大光腔结构,脊形波导980nm单模InGaAs/GaAs/AlGaAs多量子阱半导体激光器在保持大功率光输出的同时获得了较小的垂直发散角.结果表明波导中的光功率密度可以降低,获得了大于400mW、斜率效率0.89W/A的输出光功率,垂直方向远场发散角也降低到23°.     

High-performance 980-nm ridge waveguide lasers with a nearly circular beam

We report high-performance 980-nm ridge waveguide quantum-well lasers with extremely low vertical beam divergence of 13/spl deg/. A very small aspect ratio of 1.6 is obtained at high operating power of 900 mW. In addition to the more circular beam, low threshold, high efficiency, high characteristic temperature, and high output power of over 1.18 W are achieved. The fiber coupled output power can be as high as 680 mW with fiber Bragg grating stabilization. Excellent wavelength and power stability are also demonstrated.     

High-power 980-nm ridge waveguide laser diodes including an asymmetrically expanded optical field normal to the active layer

We propose a new ridge waveguide laser diode (LD) which supports an asymmetrically expanded optical field normal to the active layer in order to increase the maximum kink-free output power and reduce the aspect ratio of output beams. The dependence of maximum kink-free output power on facet reflectivity was analyzed from the viewpoint of the total optical power in the cavity. It was clarified that the maximum kink-free output power is influenced by the facet reflectivity which affects the refractive index changes of the ridge region via the total optical power in the cavity. More than 600 mW of maximum kink-free output power and an aspect ratio of less than 2.5 were achieved in experiments with 980-nm ridge waveguide LDs by means of this proposed new structure.     

Low-threshold InGaAsP ridge waveguide lasers at 1.3 µm

The ridge waveguide configuration is shown to provide reliable low-threshold fundamental-transverse-mode lasers that are readily fabricated. Two variants are described: in the simple ridge laser, the 1.3 μm bandgap active layer is sandwiched between InP layers and in the cladded ridge, the active layer is surrounded by 1.1 μm bandgap InGa AsP. Thresholds as low as 34 mA and efficiencies as high as 66 percent are observed. Output power is linear to more than 12 mW. Several lasers have been operated at 30°C for over 1500 h without measurable degradation. Selected lasers exhibit stabilized longitudinal mode behavior over extended temperature and current ranges. The potential manufacturability of this device is its most attractive feature.     

Fabrication of wavelength-tunable butt-coupled sampled grating DBR lasers using planar buried heterostructure

Planar buried heterostructure (PBH) was adopted to fabricate a sampled grating distributed Bragg reflector laser diode (SGDBR-LD) having a low threshold current and a stable fundamental transverse mode. The etching process for butt-coupling was optimized to improve the reproducibility and the uniformity of the butt-coupled waveguide. The maximum output power of the fabricated SGDBR-LD was 20 mW at 200-mA continuous-wave operation at 25/spl deg/C. The output power was measured 10 and 9 mW higher than those of ridged waveguide (RWG) structure and buried ridge stripe (BRS), and the threshold current was slightly higher than those of RWG and BRS. The spectra of 25 channels spaced 50 GHz within the tuning range of 44.4 nm was obtained by a precise control of SG and phase control currents. The side-mode suppression ratio of more than 35 dB was obtained in the whole tuning range. The output power variation was less than 5 dB, which is 4 dB smaller than that of RWG structure.     

Improvement of kink-free output power by using highly resistive regions in both sides of the ridge stripe for 980-nm laser diodes

Suppressing the lateral expansion of driving current by forming highly resistive regions at both sides of the ridge stripe in ridge-waveguide-type 980-nm laser diodes leads to an enhanced kink-free output power. The highly resistive regions are formed by hydrogen passivation of p-type carrier (Zn) on the plasma exposure in a mixture gas of methane and hydrogen. A simulation predicted a decrease in local gain in the lateral direction at both sides of the ridge stripe. Fabricated laser diodes with the highly resistive regions exhibit kink-free output power of over 500 mW, showing an increase in kink-free power of 85 mW on average with an increase of slope efficiency of about 10% compared to those without highly resistive regions.     

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.     

50 mW CW-operated single-mode surface-emitting AlGaAs lasers with45° total reflection mirrors

The authors report on the fabrication and testing of surface-emitting AlGaAs 3.5 μm ridge lasers with etched mirrors and 45° internal deflectors. The 45° mirror coupling coefficient and the resulting threshold current penalty have been analyzed theoretically and experimentally. A surface-emitted optical power of 50 mW CW at 26 mA threshold current and external differential efficiency of 57% has been achieved in lateral fundamental-mode operation. The optical power density of 14 mW CW per micrometer ridge width is the highest reported to date and produces two-dimensional surface-emitting laser arrays of diffraction-limited beam quality suitable for optical storage applications     

High-power and highly reliable 780 nm band AlGaAs laser diodes withrectangular ridge structure

A record light output power of 240 mW has been achieved for the 780 nm band AlGaAs laser diodes by using a rectangular ridge structure. The laser diodes have been operated for >1000 h at 60°C under 150 mW pulsed operation     

AlGaAs/GaAs visible ridge waveguide laser with multicavity structure

Ridge waveguide lasers of two different cavity configurations are described. First is the multisection ridge laser structure in which the longitudinal mode selection due to the coupled-cavity effect was observed and single-frequency operation was achieved. In this structure, stable single-transverse-mode operation was ensured by the central 5 μm wide section, and the beam waist and power output were enlarged by the outer 10 μm wide sections. Output power of more than 13 mW under pulsed excitation was obtained. The second configuration is the shallow groove ridge laser in which the 5 μm wide shallow groove terminates slightly above the active region and provides an index perturbation that contributes to mode selection. All the lasers are designed to emil in the visible range between 7600 and 7900 Å. The shortest observed wavelength is 7570 Å, and can be seen by the naked eye.     

Highly Efficient +5-dB Parametric Gain Conversion Using Direct-Bonded PPZnLN Ridge Waveguide

We fabricated a 50-mm-long ZnO-doped quasi-phase-matched LiNbO ridge waveguide by employing the direct bonding and dry etching techniques. We obtained a second-harmonic generation conversion efficiency of 2400%/W and a second-harmonic output power of 148 mW with a pump power of 160 mW. We demonstrated 1.55-m-band wavelength conversion based on a cascade scheme. A parametric conversion gain of 5 dB was successfully achieved.     

一种GaAs/GaAlAs分别限制单量子阱锁相列阵激光器

本文描述一种由MOCVD生长的GaAs/GaAlAs 分别限制单量子阱片子制作的锁相列阵大功率激光器.由十个单横模器件耦合而成的列阵器件,其阈值电流为67mA,线性输出功率大于500mW,微分量子效率达60％.列阵器件由强耦合区和弱耦合区构成,考察了强耦合区的几何结构对耦合模即输出远场分布的影响.     

High power 980 nm ridge waveguide lasers with etch-stop layer

For the first time, the use of an etch-stop layer to precisely control the mesa height in ridge waveguide InGaAs/GaAs lasers is reported. These 980 nm devices emit up to 180 mW of total power in the fundamental spatial mode and lase in a single frequency with sidemode suppression ratios of greater than 25 dB.<>     

Improvement of kink and beam steering characteristics of 0.98-μmGaInAs-GaInP high-power lasers utilizing channel ion implantation

We demonstrate a kink and beam steering free operation of 0.98-μm GaInAs-GaInP high-power ridge waveguide (RW) lasers utilizing channel ion implantation. The ion-implanted regions along the both sides of the ridge effectively suppressed the excitation of higher order lateral modes, which causes beam steering and kink. The maximum power without beam steering and kink has been achieved over 250 mW for channel ion-implanted RW lasers with 1.8-3.7-μm ridge width, compared to 120-mW maximum power without the channel ion implantation     

High power operation of GaInAsP/GaInAs MQW ridge lasers emitting at 1.48 mu m

Multi-quantum-well (MQW) ridge lasers have been produced with CW light outputs in excess of 100 mW at 500 mA. The wavelength of operation is 1480 nm and the lasers are suitable for pumping erbium-doped-fibre amplifiers. These are the highest power ridge lasers yet produced in the 1500 nm wavelength region.<>     

900-mW high brightness buried ridge lasers by selective areaepitaxy

A study has been made of high power single lateral mode buried ridge lasers fabricated by selective area epitaxy. Several ridge thicknesses have been evaluated simultaneously in a single fabrication run. These lasers operate purely in the fundamental mode to output powers in excess of 450 mW, after which they are subject to beam steering or higher order mode operation. For weakly guided lasers, the output remains in a narrow lobe [full-width at half-maximum (FWHM)] = 4°-6°, stable at a given current value, up to output powers of 900 mW in CW tests