High-speed and high-power 1.3 mu m InGaAsP/InP selective proton-bombarded buried crescent lasers with optical field attenuation regions

High-speed and high-power InGaAsP/lnP selective proton-bombarded buried crescent (SPB-BC) lasers with optical field attenuation regions were reported. The defect of proton bombardment can not affect the lifetime of the SPB-BC laser because the optical field attenuation region obstructs the growth and propagation of defects. A CW light output over 115 mW was achieved at room temperature using a 500 mu m long cavity SPB-BC laser. The 3 dB bandwidth was 8.5 GHz, and the lifetime was about 8.5 x 10(5) h. The capacitance of four kinds of current blocking structures was first measured in our experiment, and the results shown that the capacitance of proton-bombarded pnpn structure was not only less than that of pnpn current blocking structure, but also less than that of semi-insulating Fe-InP structure.

A novel 1.3-mu m high T-0 AlGaInAs/InP strained-compensated multi-quantum well complex-coupled distributed feedback laser diode

A 1.3-mu m AlGaInAs/InP buried heterostructure (BH) stripe distributed feedback laser with a novel AlInAs/InP complex-coupled grating grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) is proposed and demonstrated. A high characteristic temperature (T-0 = 90K between 20-80 degrees C) and temperature-insensitive slope efficiency (0.25 dB drop from 20 to 80 degrees C) in 1.3 mu m AlGaInAs/InP DFB lasers was obtained by introducing AI(Ga)InAs graded-index separate-confinement heterostructure (GRINSCH) layers and a strained-compensated (SC) multi-quantum well (MQW).

Structural and optical characteristics of self-organized InAs quantum dots grown on GaAs (3 1 1)A substrates

Structural and optical investigations of InAs QDs grown on GaAs (3 1 1)A by molecular beam epitaxy (MBE) were reported. InAs/GaAs (3 1 1)A QDs with nonconventional, faceted, arrowhead-like shapes aligned in the [ - 2 3 3] direction have been disclosed by AFM image. Low defect and dislocation density on the QDs interfaces were indicated by the linear dependence of photoluminescence (PL) intensity on the excitation power. The fast red shift of PL energy and the monotonic decrease of FWHM with increasing temperature were observed and explained by carriers being thermally activated to the energy barrier produced by the wetting layer and then retrapped and recombined in energetically low-lying QDs states. (C) 1999 Elsevier Science B.V. All rights reserved.

1.3μm单模低阈值、长寿命激光器的研制

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1.3微米基横模、低阈值、长寿命激光器

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长波1.3 和1.5μm无致冷单模激光器研究

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长波1.3 和1.5um无致冷单模激光器研究

于G批量导入至Hzhangdi

Theoretical analysis of modal gain in p-doped 1.3 mu m InAs/GaAs quantum dot lasers

A theoretical study of modal gain in p-doped 1.3 mu m InAs/GaAs quantum dot (QD) lasers is presented. The expression of modal gain is derived, which includes an effective ratio that describes how many QDs contribute to the modal gain. The calculated results indicate that the modal gain with the effective ratio is much smaller than that without the effective ratio. The calculated maximum modal gain is is a good agreement with the experimental data. Furthermore, QDs with lower height or smaller aspect ratio are beneficial in achieving a larger maximum modal gain that leads to lower threshold current density and higher differential modal gain. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Effect of noncoherent islands on the optical properties of the 1.3 mu m InAs/GaAs quantum dots during rapid thermal annealing

The effect of thermal annealing of InAs/GaAs quantum dots (QDs) with emission wavelength at 1.3 mu m have been investigated by photoluminescence (PL) and transmission electron microscopy (TEM measurements. There is a dramatic change in the A spectra when the annealing temperature is raised up to 800 degrees C: an accelerated blushifit of the main emission peak of QDs together with an inhomogeneous broadening of the linewidth. The TEM images shows that the lateral size of normal QDs decreases as the annealing temperature is increased, while the noncoherent islands increase their size and densit. A small fraction of the relative large QDs contain dislocations when the annealing temperature increases up to 800 degrees C. The latter leads to the strong decrease of the PL intensity.

1.3 mu m high indium content (42.5%) GaInNAs/GaAs quantum wells grown by molecular beam epitaxy

High structural and optical quality 1.3 mu m GaInNAs/GaAs quantum well (QW) samples with 42.5% indium content were successfully grown by molecular beam epitaxy. The growth of well layers was monitored by reflection high-energy electron diffraction (RHEED). Room temperature photoluminescence (PL) peak intensity of the GaIn0.425NAs/GaAs (6 nm / 20 nm) 3QW is higher than, and the full width at half maximum (FWHM) is comparable to, that of In0.425GaAs/GaAs 3QW, indicating improved optical quality due to strain compensation effects by introducing N to the high indium content InGaAs epilayer. The measured (004) X-ray rocking curve shows clear satellite peaks and Pendellosung fringes, suggesting high film uniformity and smooth interfaces. The cross sectional TEM measurements further reveal that there are no structural defects in such high indium content QWs. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Large-Signal Performance of 1.3 mu m InAs/GaAs quantum-dot lasers

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Hydride Vapor Phase Epitaxy Growth of Semipolar, 10(1)over-bar(3)over-barGaN on Patterned m-Plane Sapphire

We have investigated the hydride vapor-phase epitaxy growth of (10 (1) over bar(3) over bar)-oriented GaN thick films on patterned sapphire substrates (PSSs) (10 (1) over bar0). From characterization by atomic force microscopy, scanning electron microscopy, double-crystal X-ray diffraction, and photoluminescence (PL), it is determined that the crystalline and optical qualities of (10 (1) over bar(3) over bar) GaN epilayers grown on the cylindrical PSS are better than those on the flat sapphire. However, two main crystalline orientations (10 (1) over bar(3) over bar) and (11 (2) over bar2) dominate the GaN epilayers grown on the pyramidal PSS, demonstrating poor quality. After etching in the mixed acids, these (10 (1) over bar(3) over bar) GaN films are dotted with oblique pyramids, concurrently lining along the < 30 (3) over bar2 > direction, indicative of a typical N-polarity characteristic. Defect-related optical transitions of the (10 (1) over bar(3) over bar) GaN epilayers are identified and detailedly discussed in virtue of the temperature-dependent PL. In particular, an anomalous blueshift-redshift transition appears with an increase in temperature for the broad blue luminescence due to the thermal activation of the shallow level.

高性能1.3 μm InAs/GaAs量子点激光器的研究

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Temperature-dependent modulation characteristics for 1.3 mu m InAs/GaAs quantum dot lasers

Temperature-dependent modulation characteristics of 1.3 mu m InAs/GaAs quantum dot (QD) lasers under small signals have been carefully studied at various bias currents. Based on experimental observations, it is found that the modulation bandwidth significantly increases when excited state (ES) lasing emerges at high temperature. This is attributed to additional photons emitted by ES lasing which contribute to the modulation response. A rate equation model including two discrete electron energy levels and the level of wetting layer has been used to investigate the temperature-dependent dynamic behavior of the QD lasers. Numerical investigations confirm that the significant jump for the small signal modulation response is indeed caused by ES photons. Furthermore, we identify how the electron occupation probabilities of the two discrete energy levels can influence the photon density of different states and finally the modulation rate. Both experiments and numerical analysis show that the modulation bandwidth of QD lasers at high temperature can be increased by injecting more carriers into the ES that has larger electron state degeneracy and faster carrier's relaxation time than the ground state.