High power and high efficiency operation of Al-freeInGaAs/GaInAsP/GaInP GRINSCH SQW lasers (λ≃0.98 μm)

High power and high quantum efficiency Al-free InGaAs/GaInAsP/GaInP GRINSCH SQW lasers emitting at 0.98 μm are reported. A CW output power as high as 580 mW and single lateral mode power up to 280 mW were achieved for the Al-free ridge waveguide lasers at room temperature. The lasers exhibited a high internal quantum efficiency of 99% and low internal waveguide loss of 3.2 cm^-1. A high characteristic temperature of 217 K and low threshold current density of 109 A/cm² were also obtained. The results are the best obtained for Al-free 0.98 μm pumping lasers     

InGaAs/GaAs/AlGaAs应变量子阱激光器

优化设计了既能实现较小垂直方向远场发散角,又能降低腔面光功率密度的ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变层量子阱激光器,并计算了该结构激光器实现基横模工作的脊形波导结构参数。利用分子束外延生长了ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器材料并研制出基横模输出功率大于１４０ｍＷ,激射波长为９８０ｎｍ的脊形波导应变量子阱激光器,其微分量子效率为０．８Ｗ／Ａ,垂直和平行结平面方向远场发散角分别为２８°和６．８°     

量子阱无序的窗口结构InGaAs/GaAs/AlGaAs量子阱激光器

对ＳｉＯ２薄膜在快速热退火条件下引起的空位诱导ＩｎＧａＡｓ／ＧａＡｓ应变量子阱无序和ＳｒＦ２薄膜抑制其量子阱无序的方法进行了实验研究。并将这两种技术的结合（称为选择区域量子阱无序技术）应用于脊形波导ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器，研制出具有无吸收镜面的窗口结构脊形波导量子阱激光器。该结构３μｍ条宽激光器的最大输出功率为３４０ｍＷ，和没有窗口的同样结构的量子阱激光器相比，最大输出功率提高了３６％。在１００ｍＷ输出功率下，发射光谱中心波长为９７８ｎｍ，光谱半宽为１．２ｎｍ。平行和垂直方向远场发散角分别为７．２°和３０°     

Low threshold ridge waveguide single quantum well laser processed by chemically assisted ion beam etching

Fundamental lateral mode ridge waveguide lasers have been developed utilizing chemically assisted ion beam etching. The lasers exhibited mean threshold currents of 12.6 mA with close to 100 percent yield and differential quantum efficiencies as high as 69 percent.     

AlInGaAs/AlGaAs strained quantum-well ridge waveguide lasers grownby metalorganic chemical vapor deposition

AlInGaAs/AlGaAs strained quantum-well ridge waveguide diode lasers with an emission wavelength of 890 nm are presented. These devices exhibit both single spatial and longitudinal mode operation up to 30 mW of optical output power. A CW threshold current of 13 mA was obtained for a 5-μm-wide ridge waveguide having a cavity length of 500 μm. The differential quantum efficiency was 52%. The lateral and perpendicular far-field radiation patterns (FWHM) from the laser were 6° and 51°, respectively. Reliability testing on uncoated gain-guided lasers made from the same wafer showed no sudden death failures and degradation rates as low as 4.6%/kh     

1.3-/spl mu/m continuously tunable distributed feedback laser with constant power output based on GaInNAs-GaAs

We have investigated tunable distributed-feedback (DFB) lasers based on GaInNAs quantum wells grown by molecular-beam epitaxy. Three-section tunable DFB lasers were fabricated by patterning laterally gain coupled binary superimposed gratings perpendicular to a ridge waveguide. The discrete tuning range covers 24 nm with sidemode suppression ratios of about 35 dB. The lasers were tuned continuously over a range of over 10 nm with a constant power output of 15 mW per facet.     

High-speed modulation of strain-compensated InGaAs-GaAsP-InGaP multiple-quantum-well lasers

Small signal direct modulation characteristics of InGaAs-GaAsP-InGaP multiple quantum well ridge waveguide lasers (4.5/spl times/220 /spl mu/m/sup 2/) are described. The compressive strain of four InGaAs quantum wells is compensated by the tensile strain of GaAsP barriers. The lasers have a threshold current of 8 mA and an internal differential quantum efficiency of 80%. A 3-dB bandwidth of 25 GHz is obtained at 54 mA. It is found that the strain-compensated lasers have a K factor as low as 0.15 ns, implying a maximum 3-dB bandwidth of 59 GHz.     

Tapered quantum cascade lasers operating at 9.0μm

The tapered quantum cascade lasers operating at about 9.0μm are reported. In contrast to the common ridge waveguide laser, tapered devices give rather small horizontal beam divergence. Performances of devices with identical 11μm ridge waveguide sections and different tapered gain sections are comparatively studied. The optimal taper angle of 3° leads to a relative high output power and a very small horizontal beam divergence of 7.1°.     

Modal Analysis of Large Spot Size, Low Output Beam Divergence Quantum-Dot Lasers

Large spot size ridge waveguide lasers utilizing a low modal gain single quantum dot layer emitting at 925 nm were designed and fabricated. Ridge waveguides with width <3 mum emit in a single transverse mode with a low transverse full-width at half-maximum divergence of 20deg. Wider ridges initially lase in the first-order transverse mode before collapsing to the fundamental mode. This characteristic is explained by a thermally induced increase in the refractive index of the waveguide core. All lasers operate in a single lateral mode     

Multi-λ ridge waveguide gain-coupled DFB laser array

Multi-wavelength gain-coupled quantum well DFB laser array has been fabricated on an InP substrate by simply varying the ridge waveguide width of the element lasers. Owing to the gain-coupling effect, seven singlemode lasing wavelengths around 1.55 μm with ~2 nm spacing were obtained simultaneously. The lasers had low threshold currents and small beam divergence     

Wide range tunable laterally coupled distributed-feedback lasers based on InGaAs-GaAs quantum dots

The authors have investigated tunable distributed feedback (DFB) lasers based on InGaAs quantum dots grown by molecular beam epitaxy. Two-section tunable DFB lasers were fabricated by patterning laterally gain coupling binary superimposed gratings perpendicular to the ridge waveguide. Side-mode suppression ratios of up to 40 dB have been achieved. The tuning range covers 30 nm.     

High temperature, high power InGaAs/GaAs quantum-well lasers withlattice-matched InGaP cladding layers

The authors report the high-temperature and high-power operation of strained-layer InGaAs/GaAs quantum well lasers with lattice-matched InGaP cladding layers grown by gas-source molecular beam epitaxy. Self-aligned ridge waveguide lasers of 3-μm width were fabricated. These lasers have low threshold currents (7 mA for 250-μm-long cavity and 12 mA for 500-μm-long cavity), high external quantum efficiencies (0.9 mW/mA), and high peak powers (160 mW for 3-μm-wide lasers and 285 mW for 5-μm-wide laser) at room temperature under continuous wave (CW) conditions. The CW operating temperature of 185°C is the highest ever reported for InGaAs/GaAs/InGaP quantum well lasers, and is comparable to the best result (200°C) reported for InGaAs/GaAs/AlGaAs lasers     

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.<>     

Tunable GaInNAs lasers with photonic crystal mirrors

We present results of tunable GaInNAs lasers with photonic crystal (PhQ mirrors, fabricated from GaAs-AlGaAs layers with a double GaInNAs quantum well emitting at IR wavelength. The devices are realized as ridge waveguide lasers with two coupled segments and a total length between 240 and 580 pm. PhC blocks with different thicknesses are used for the back and front mirror as well as for the intermediate reflector between the two segments. The lasers have threshold currents around 20 mA and output powers up to 6 mW. Tuning of the laser emission over 30 nm is achieved by a variation of the currents injected into the two segments.     

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.     

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.     

Low threshold current high-temperature operation of InGaAs/AlGaAsstrained-quantum-well lasers

The authors report improved high-temperature characteristics for In_0.2Ga_0.8As strained-quantum-well ridge waveguide lasers with an optimized cavity design. They have fabricated In_0.2 Ga_0.8As lasers that operate CW at up to 220°C with over 9-mW output power. At 200°C the threshold current is as low as 15.9 mA for a 400-μm-long laser with 35/98% reflectivity facets. Optimization of the laser cavity also improves the high-temperature operation of quantum-well lasers in other material systems; GaAs quantum well lasers that operate at up to 220°C CW have been fabricated     

InGaAsP ridge waveguide distributed feedback lasers operating near 1.55 µm

Fabrication and performance of ridge waveguide distributed feedback lasers grown by liquid phase epitaxy for operation in the 1.50-1.58 μm spectral region have been studied. These lasers incorporate first- and second-order diffraction gratings written by the electron beam lithography and optical holography and defined by wet chemical etching and novel ion-beam-milling techniques. Ridge waveguides were formed by post-regrowth processing and heteroepitaxial ridge overgrowth. Distributed feedback ridge lasers were characterized by room temperature CW threshold currents as low as 40 mA, two facet external quantum efficiencies of up to 40 percent and stable transverse mode operation up to the output power of 10 mW. In strongly coupled devices, even with a cleaved resonator, the Bragg mode intensity exceeds that of the residual Fabry-Perot modes by a factor of 4000:1. Stable, single longitudinal mode operation was obtained under modulation rates as high as 4 GHz and error free transmission experiments over 60-km lengths of single mode fiber reproducibly performed at data rates as high as 2 Gbit/s.     

7.8 GHz small-signal modulation bandwidth of 1.3 μm DQWGaInAsN/GaAs laser diodes

High frequency characterisation of double quantum well GaInAsN laser diodes emitting at 1.28 μm is reported. The 3 dB bandwidth of ridge waveguide lasers was measured to be 7.8 GHz at 120 mA under CW operation demonstrating the potential for high speed operation of these devices     

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.