High-temperature continuous-wave operation of 1310 nm InAs/GaAs quantum dot lasers

Here we report 1.3μm electrical injection lasers based on InAs/GaAs quantum dots(QDs)grown on a GaAs substrate,which can steadily work at 110-℃without visible degradation.The QD structure is designed by applying the Stranski-Krastanow growth mode in solid source molecular beam epitaxy.The density of InAs QDs in the active region is increased from 3.8×10^(10)cm^(-2)to 5.9×10^(10)cm^(-2).As regards laser performance,the maximum output power of devices with lowdensity QDs as the active region is 65 m W at room temperature,and that of devices with the high-density QDs is 103 mW.Meanwhile the output power of high-density devices is 131 mW under an injection current of 4 A at 110-℃.

Continuous-wave operation of InAs/InP quantum dot tunable external-cavity laser grown by metal-organic chemical vapor deposition

We demonstrate high-performance broadband tunable external-cavity lasers(ECLs) with the metal-organic chemical vapor deposition(MOCVD) grown In As/In P quantum dots(QDs) structures. Without cavity facet coatings, the 3-d B spectral bandwidth of the Fabry–Perot(FP) laser is approximately 10.8 nm, while the tuning bandwidth of ECLs is 45 nm.Combined with the anti-reflection(AR)/high-reflection(HR) facet coating, a 92 nm bandwidth tuning range has been obtained with the wavelength covering from 1414 nm to 1506 nm. In most of the tuning range, the threshold current density is lower than 1.5 k A/cm2. The maximum output power of 6.5 m W was achieved under a 500 m A injection current.All achievements mentioned above were obtained under continuous-wave(CW) mode at room temperature(RT).

1.3μm InGaAs/InAs/GaAs Self-Assembled Quantum Dot Laser Diode Grown by Molecular Beam Epitaxy

The growth of multi-layer InGaAs/InAs/GaAs self-assembled quantum dots （QDs） by molecular beam epitaxy （MBE） is investigated,and a QD laser diode lasing at 1.33μm in continuous operation mode at room temperature is reported. The full width at half maximum of the band edge emitting peaks of the photoluminescence （PL） spectra at room temperature is less than 35meV for most of the multi-layer QD samples,revealing good,reproducible MBE growth conditions. Moreover,atomic force microscopy images show that the QD surface density can be controlled in the range from 1×10^10 to 7 ×10^10 cm^-2 . The best PL properties are obtained at a QD surface density of about 4×10^10cm^-2. Edge emitting lasers containing 3 and 5 stacked QD layers as the active layer lasing at room temperature in continuous wave operation mode are reported.

Optimization of InAs/GaAs quantum-dot structures and application to 1.3-μm mode-locked laser diodes

The self-assembled growth of InAs/GaAs quantum dots by molecular beam epitaxy is conducted by optimizing several growth parameters, using a one-step interruption method after island formation. The dependence of photoluminescence on areal quantum-dot density is systematically investigated as a function of InAs deposition, growth temperature and arsenic pressure. The results of this investigation along with time-resolved photoluminescence measurements show that the com- bination of a growth temperature of 490℃, with a deposition rate of 0.02 ML/s, under an arsenic pressure of 1×10^-6 Torr （1 Torr = 1.33322×10^2 Pa）, provides the best compromise between high density and the photoluminescence of quantum dot structure, with a radiative lifetime of 780 ps. The applicability of this 5-layer quantum dot structure to high-repetition-rate pulsed lasers is demonstrated with the fabrication and characterization of a monolithic InAs/GaAs quantum-dot passively mode-locked laser operating at nearly 1300 nm. Picosecond pulse generation is achieved from a two-section laser, with a 19.7-GHz repetition rate.

Simulation and Analysis of Carrier Dynamics in the InAs/GaAs Quantum Dot Laser, Based upon Rate Equations

In this paper, simulation of InAs/GaAs quantum dot (QD) laser is performed based upon a set of eight rate equations for the carriers and photons in five energy states. Carrier dynamics in these lasers were under analysis and the rate equations are solved using 4th order Runge-Kutta method. We have shown that by increasing injected current to the active medium of laser, switching-on and stability time of the system would decrease and power peak and stationary power will be increased. Also, emission in any state will start when the lower state is saturated and remain steady. The results including P-I characteristic curve for the ground state (GS), first excited state (ES1), second excited state (ES2) and output power of the QD laser will be presented.

Photoluminescence and lasing properties of InAs/GaAs quantum dots grown by metal-organic chemical vapour deposition

Photoluminescence （PL） and lasing properties of InAs/GaAs quantum dots （QDs） with different growth procedures prepared by metalorganic chemical vapour deposition are studied. PL measurements show that the low growth rate QD sample has a larger PL intensity and a narrower PL line width than the high growth rate sample. During rapid thermal annealing, however, the low growth rate sample shows a greater blueshift of PL peak wavelength. This is caused by the larger InAs layer thickness which results from the larger 2-3 dimensional transition critical layer thickness for the QDs in the low-growth-rate sample. A growth technique including growth interruption and in-situ annealing, named indium flush method, is used during the growth of GaAs cap layer, which can flatten the GaAs surface effectively. Though the method results in a blueshift of PL peak wavelength and a broadening of PL line width, it is essential for the fabrication of room temperature working QD lasers.

MOVPE growth of InAs quantum dots for mid-IR applications

InAs quantum dots (QDs) grown on InxGa1-xAs/InP matrix by low pressure metal organic vapor phase epitaxy (LP-MOVPE) in nitrogen ambient were studied. Formation of the InAs QDs with different growth conditions was investigated. To improve the dot size uniformity, a two-step growth method was used and investigated. It is found that morphology of the InAs QDs formed on such InxGa1-xAs/InP matrix is very sensitive to the growth conditions. InAs QDs with high density of 1.3×1010 cm?2 are grown by using S-K growth method with fast growth rate. Using the two-step growth method, the InAs QDs size uniformity improves by 63% and 110% compared that of the dots grown by ordinary S-K method and ALE method, respectively. Narrow photoluminescence (PL) emission spectrum of the QDs grown by using the two-step growth method is received. FWHM of the PL curve is measured at 26 meV and the peak emission wavelength is larger than 2.3 μm at 77 K.

InP衬底上LP-MOCVD生长InAs自组装量子点

报道利用低压金属有机化学气相沉积（LP－MOCVD）技术在（001）InP衬底上生长InAs自组装量子点的结果，用光致发光技术观察到较强的室温光荧光谱，其峰值波长约为1603um，分布在1300um^1700um范围内。

InAs/GaAs量子点材料和激光器

介绍了近年来长波长InAsG/aAs量子点材料的生长、结构性质和量子点激光器的研究进展。

InAs/GaAs quantum dot laterally coupled distributed feedback lasers at 1.3μm

We report the InAs/GaAs quantum dot laterally coupled distributed feedback(LC-DFB)lasers operating at room temperature in the wavelength range of 1.31μm.First-order chromium Bragg gratings were fabricated alongside the ridge waveguide to obtain the maximum coupling coefficient with the optical field.Stable continuous-wave single-frequency operation has been achieved with output power above 5 mW/facet and side mode suppression ratio exceeding 52 dB.Moreover,a single chip integrating three LC-DFB lasers was tentatively explored.The three LC-DFB lasers on the chip can operate in single mode at room temperature,covering the wavelength span of 35.6 nm.

1550nm InAs/GaAs量子点调Q光纤激光器

调Q光纤激光器在光纤传感、激光雷达、激光加工和光纤通信等众多方面有着广泛的应用。半导体量子点(QD)由于具有较高的损伤阈值和宽光谱特性,是一种优良的可饱和吸收体(SA),但是目前制备发光中心波长为1550 nm的QD SA依然是一个巨大的挑战。通过在分子束外延(MBE)生长InAs QD过程中加入两次间断制备了1550 nm InAs/GaAs量子点半导体可饱和吸收镜(QD-SESAM),并通过构建光纤直线腔,研制出发光中心波长约为1550 nm的被动调Q光纤激光器。该激光器最大输出功率约为2.5 mW,实现了55 kHz的重复频率,同时达到了1.45μs的脉冲宽度和45.36 nJ的单脉冲能量,表现出了InAs/GaAs QD材料在1550 nm调Q光纤激光器应用中的巨大潜力。

High-performance InAs/GaAs quantum dot laser with dot layers grown at 425℃

We investigate InAs/GaAs quantum dot （QD） lasers grown by gas source molecular beam epitaxy with different growth temperatures for InAs dot layers. The same laser structures are grown, but the growth temperatures of InAs dot layers are set as 425 and 500℃, respectively. Ridge waveguide laser diodes are fabricated, and the characteristics of the QD lasers are systematically studied. The laser diodes with QDs grown at 425 ~C show better performance, such as threshold current density, output power, internal quantum efficiency, and characteristic temperature, than those with QDs grown at 500℃. This finding is ascribed to the higher QD density and more uniform size distribution of QDs achieved at 425℃.

Low phase noise and quasi-tunable millimeter-wave generator using a passively In As/InP mode-locked quantum dot laser

A low phase noise millimeter-wave(MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Pérot(F-P) quantum dot mode-locked laser. A novel method is proposed to generate low phase noise MMW signal, which is simply based on a commercial off-the-shelf dual-driven Li Nb O3 Mach-Zehnder modulator and a passively F-P quantum dot mode-locked laser. MMW signal with the frequency of 30 GHz, 45 GHz and 90 GHz respectively is obtained experimentally. Single-sideband phase noise of the 30 GHz and 45 GHz MMW signal is-112 d Bc/Hz and-106 d Bc/Hz at an offset of 1 k Hz, respectively. The linewidth of the 30 GHz and 45 GHz MMW signal is about from 225 Hz and 239 Hz. This is considered a very simple MMW generator with a quasi-tunable broadband and ultra-low phase noise.

大范围连续调谐的InAs／InP(100)外腔量子点激光器

实现了一种工作在连续波(CW)模式下InAs/InP(100)外腔量子点激光器(EC-QDL)。激光器采用小型化的Littrow外腔结构,中心波长为1.6μm且输出光方向固定。在室温条件下,对InAs/InP(100)量子点外腔激光器进行了一系列性能测试。实验结果表明,器件的单模大范围波长调谐达56.5nm,覆盖波长从1 566.9到1 623.4nm,获得30GHz的无跳模连续调谐范围,在中心波长1.6μm附近单模输出功率达8 mW,并在无跳模连续调谐范围内获得了30dB以上的边模抑制比(SMSR)。

Quantum dot lasers and integrated optoelectronics on silicon platform Invited Paper

Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent progress of the direct epitaxy and fabrication of quantum dot （QD） lasers and integrated guided-wave devices on silicon. This approach involves the development of molecular beam epitaxial growth of self- organized QD lasers directly on silicon substrates and their monolithic integration with amorphous silicon waveguides and quantum well electroabsorption modulators. Additionally, we report a preliminary study of long-wavelength （〉 1.3 μm） QD lasers grown on silicon and integrated crystalline silicon waveguides using membrane transfer technology.

生长停顿对量子点激光器的影响

在 In As自组织量子点的 Ga As覆盖层中引入生长停顿 ,将这种量子点结构作激光器的有源区 ,与不引入生长停顿的量子点激光器进行对比后发现 :生长停顿可以降低激光器的阈值电流 ,提高其特征温度 ,改善激光波长的温度稳定性 .简单的分析表明 ,量子点中的能带填充效应影响了激光波长的温度特性 .

1.08μm InAs/GaAs量子点激光器光学特性研究

介绍了InAs/GaAs量子点激光器的材料生长,器件制备及其光学特性的研究。器件为条宽100μm,腔长1600μm未镀膜激器。室温阈值电流密度为221A/cm2,激射波长为1.08μm,连续波工作最大光功率输出为2.74W(双面),外微分效率为88％,经50oC,1000h老化,仍有>1.2W的光功率输出。

高性能InAs/GaAs量子点外腔激光器

为了获得高性能的量子点外腔激光器(ECL),利用InAs/GaAs量子点Fabry-Perot(FP)腔激光器研制了光栅外腔可调谐ECL。对InAs/GaAs量子点ECL进行了一系列的性能测试,主要包括单模稳定性测试、单模调谐范围测试、阈值电流密度测试、无跳模连续调谐测试和输出功率测试。在室温条件下获得了24.6nm的连续调谐范围,覆盖波长从999.2nm到1 023.8nm,并且实现了波长无跳模连续调谐。在调谐范围内最低阈值电流密度为1 525A/cm2,而且在中心波长处获得的单模输出功率为15mW,单模边模抑制比(SMSR)高达35dB。研究结果表明,通过构建光栅外腔可以实现高性能的InAs/GaAs量子点ECL。

p型掺杂1.3μm InAs/GaAs量子点激光器的最大模式增益特性的研究

对p型掺杂1.3μm InAs/GaAs量子点激光器的最大模式增益进行了实验和理论分析.实验上,测量了不同腔长激光器阈值电流密度与总损耗的对应关系,拟合出的最大模式增益为17.5cm-1,与相同结构非掺杂量子点激光器的最大模式增益一致.同时理论分析表明,p型掺杂对InAs/GaAs量子点激光器的最大模式增益并无影响,并且最大模式增益的计算结果与实验值相符.具有较小高度或高宽比的量子点能达到更高的最大模式增益,而较高的最大模式增益对p型掺杂1.3μm InAs/GaAs自组织量子点激光器在光通信系统中的应用具有重要意义.

基于量子点可饱和吸收镜的锁模激光器

锁模光纤激光器在工业加工、光通信、光学传感等领域有广泛的应用。由于在GaAs基板上制备的InAs量子点(QD)半导体可饱和吸收镜(QD-SESAM)增益谱较宽、成本较低,将其应用于锁模光纤激光器具有非常大的潜力。然而,生长发光中心波长(λ)为1550 nm的高性能QD-SESAM仍然十分困难。采用分子束外延(MBE)生长制备了1550 nm GaAs基InAs QD-SESAM,通过在SESAM上表面生长厚度为λ/4的SiO_(2)层,将QD-SESAM的调制深度提升至1.4%。使用这种新型的QD-SESAM优化了耦合效率,成功地构建了稳定的环形腔被动锁模掺铒光纤激光器,其斜率效率为2.2%,脉冲宽度为2 ps,重复频率为16.5 MHz,最大输出功率约为4.1 mW。结果表明,这种带有λ/4厚度SiO_(2)层的QD-SESAM在制备高性能锁模激光器方面具有非常大的应用潜力。