GaAlAs buried-heterostructure lasers grown by a two-step MOCVD process

The fabrication and characterisation of GaAlAs buried-heterostructure laser diodes having low threshold currents (10 mA), high uniformity and planar surface structure, and grown exclusively by metalorganic chemical vapour deposition (MOCVD) are described. Single-longitudinal and transverse-mode operation of these devices has been observed. In addition, considerable suppression of relaxation resonance effects has been observed in the high-frequency modulation of these devices.     

Low threshold GaAs/GaAlAs BH lasers with ion-beam-etched mirrors

We report the use of the ion-beam etching (IBE) technique to produce GaAs/GaAlAs BH lasers with one etched and one cleaved mirror facet. Low threshold currents of 12 mA have been measured in devices with 100 ?m-long cavities.     

Temporal and spectral characteristics of rapidly gain-switched GaAs/GaAlAs buried-heterostructure lasers

The temporal and spectral output of GaAs/GaAlAs buried-heterostructure lasers under excitation with 60 ps electrical pulses is investigated for different DC bias conditions. Optical pulses comparable in width to the electrical pulses can be obtained only if the DC bias is below or close to threshold, where multimode emission is observed. For DC bias well above threshold the laser remains single-mode; however, the optical pulses are considerably broadened.     

Low threshold current GaAs/GaAlAs GRIN-SCH stripe lasers grown by OMVPE

The letter describes the characteristics of stripe lasers formed in GaAs/GaAlAs single-quantum-well graded-composition separate-confinement heterostructures (GRIN-SCH) grown by low-pressure organometallic vapour phase epitaxy (LP-OMVPE). We show that the low threshold current density that has been achieved with the GRIN-SCH structure allows low threshold currents (38 mA) to be achieved in a simple gain-guided stripe-geometry laser. These low thresholds have been obtained without resorting to a complex nonplanar (lower yield) technology, and it is shown that the good uniformity offered by OMVPE is maintained through to the mounted device stage.     

Channelled-substrate narrow-stripe GaAs/GaAlAs injection lasers with extremely low threshold currents

Channelled-substrate GaAs/GaAlAs injection lasers with very narrow current-confining stripe contacts are described. They have threshold currents less than half those previously reported for this type of device. The best devices had a room-temperature threshold current of only 12 mA pulsed and 14 mA c.w. The lasers also have very good high-temperature performance and c.w. operation has been obtained up to 160°C.     

Low-threshold oxide stripe GaAs/GaAlAs lasers grown by MOCVD

MOCVD-grown insulator defined stripe GaAs/GaAlAs lasers with stripe widths of 6, 10, 20 and 150 ?m have been characterised. Uniform CW threshold currents as low as 45 mA, differential quantum efficiencies as high as 74%, and kink-free power levels as high as 20 mW/facet have been obtained in 160 ?m long, 6 ?m stripe lasers. The internal differential quantum efficiency measured from our 6 ?m stripe lasers approaches one. Single longitudinal mode operation of these lasers has also been observed.     

Controlled Zn diffusion for low threshold narrow stripe GaAlAs/GaAs DH lasers

Zn diffusion was accurately controlled to reach within the active region of a GaAlAs/GaAs DH laser. The diffused 4 µm stripe lasers have threshold currents as low as 40 mA and exhibit single longitudinal mode oscillation in a wide range of current levels.     

Submilliampere threshold buried-heterostructure InGaAs/GaAs singlequantum well lasers grown by selective-area epitaxy

Strained-layer InGaAs-GaAs-AlGaAs single quantum well buried heterostructure lasers grown by selective-area MOCVD are described. Threshold currents of 2.65 mA for an uncoated device and 0.97 mA for a coated device have been obtained. A peak optical output power of 170 mW per uncoated facet for a device with a 4 μm active region width was also achieved. Peak emissions wavelengths range from 0.956 to 1.032 μm     

低阈值的三段复合腔GaAlAs/GaAs单模激光器

本文介绍的低阈值三段复合腔GaAlAs/GaAs激光器,其最低CW阈值电流为18mA,具有稳定的单模性,外微分量子效率为50～80％,线性功率可达30mW以上。在5℃温度范围内保持单纵模工作不变,最高CW激射温度为117℃。     

Very low threshold GRIN-SCH GaAs/GaAlAs laser structure grown by OM-VPE

In a recent publication we gave preliminary results on the lasing characteristics of a GRIN-SCH GaAs/GaAlAs laser grown by OM-VPE. The parameters of this single quantum well laser have now been further optimised, and for a quantum well thickness of 60 ?, with outer confinement layers composed of Ga0.4Al0.6As, significantly lower threshold current densities have been achieved. For a broad-area laser of cavity length 413 ?m (width 140 ?m) the average threshold current density is 232 A cm?2, and this decreases to 121 A cm?2 for a chip length of 1788 ?m. We believe that these are the lowest lasing threshold current densities that have yet been reported.     

光触发GaAs/GaAlAs异质结负阻激光器

采用GaAs/GaAlAs多层液相外延技术研制成一种光触发异质结负阻激光器。文中简述了器件的工作原理和某些特性。     

Kink-free narrow-stripe proton-isolated GaAlAs/GaAs injection lasers

Totally kink-free and very-narrow-stripe proton-isolated injection lasers are presented. The standard gold-indium metal-contact bonding system has been investigated, and as a result an improved bonding technique is presented. Kink-free lasers with output power up to 20 mW have been accelerated at 80°C ambient for 1000 h without any change in thermal resistance and with an expected lifetime of above 106 h at room temperature.     

Very low threshold GaInAsP/InP double-heterostructure lasers grown by LP MOCVD

Room-temperature GaInAsP/InP DH lasers emitting at 1.3 ?m and having very low threshold current densities have been grown by LP MOCVD. Thresholds were lower than the best values reported for comparable devices grown by LPE, the lowest threshold being 430 A/cm2 for a cavity length of 950 ?m (width 150 ?m) with an active-layer thickness of d = 2200 A.     

Very low threshold current ridge-waveguide AlGaAs/GaAs single-quantum-well lasers

Ridged-waveguide AlGaAs/GaAs single-quantum-well lasers were fabricated from a molecular-beam-grown GRIN-SCH wafer in which a superlattice buffer layer was introduced. Fabricated diodes exhibited excellent lasing characteristics including a very low threshold current of 5 mA with a T0 value as high as 160 K.     

硅衬底上GaAlAs/GaAs单量子阱激光器

采用MOCVD方法在硅衬底上生长了带应力超晶格的GaAlAs/GaAs单量子阱外延片,并用质子轰击隔离法制成10微米条形单量子阱激光器.在室温下加脉冲电流(重复频率26KHz,脉宽1μs)观察到受激发射.最低阈电流92mA、激射波长849.2nm,外微分量子效率11％.     

GaAs/GaAlAs diode lasers with angled pumping stripes

Operation of DH GaAs/GaAlAs stripe contact lasers with stripes oriented nonorthogonally to the cleaved end facets of the laser is described. Such lasers, with misalignment angles ofsim2deg, do not exhibit "kinking" behavior to power levels greater than 90 mW/facet, and do not exhibit relaxation oscillations under pulsed operation. Data showing the dependence of laser wavelength, spectral half-width, transverse mode structure, facet reflectivity, and output beam angle on both stripe angle and pump current level are also presented.     

夜视系统用GaAs/GaAlAs半导体激光器

利用改进的液相外延技术生长出了ＧａＡｓ／ＧａＡｌＡｓ 夜视系统用光源。样品质量达到了设计要求。测量结果表明,样品在１０ Ｋ 下的光荧光谱的峰值波长为９２６ ．２６ ｎｍ 。利用该材料制作的激光二极管,其峰值输出功率达到１５ Ｗ。     

High-temperature operation of 1.55 ?m InGaAsP double-channel buried-heterostructure lasers grown by LPE

High-temperature operation of InGaAsP double-channel buried-heterostructure (DCBH) lasers emitting at 1.55 ?m is reported. The 1.55 ?m InGaAsP DCBH lasers have threshold currents as low as 18 mA at 20°C. The threshold current temperature sensitivity between 10°C and 75°C is characterised by a T0 value of 55?66 K. Electro-optical derivative measurements show that the 1.55 ?m InGaAsP DCBH laser does not have substantial above-threshold leakage current for junction temperatures as high as 75°C. Finally, these devices were operated at temperatures as high as 110°C, the highest CW operating temperature obtained to date for a 1.55 ?m InGaAsP laser.     

Structure dependent axial mode stability in GaAlAs/GaAs injection lasers

The influence of structure on the saturation behaviour of mode gain and the axial mode stability is investigated for different types of AlGaAs injection lasers. Both experimental and theoretical results confirm that carrier confinement along the lateral direction is effective for axial mode stabilisation.     

GaAlAs/GaAs DH激光器的发光位置研究

GaAlAs/GaAs DH激光器是一个微型的多层结构的发光器件。正常结构的发光区是在一个条形的发光区内。但是,由于工艺的改变、操作的失误等,许多器件的发光区不在理想部位。直接观察发光区的确切位置及其图样,对于了解器件性能,特别是对工艺的研究有着重要的意义。本文介绍发光区位置的确定,描述各种发光现象及其同工艺之间的可能联系。 实验结果表明:(1)全线发光有的主要与条形形成工艺有关(平面条形);有的则由外延工艺决定(沟槽衬底)。(2)带状发光,一类与外延有关,如⊿x偏小,作用区太薄等;另一类与条形形成工艺有关,如Zn的深度扩散等。(3)衬底发光主要与外延工艺有关。如沟槽衬底条形