Author
A. Larsson
Bio: A. Larsson is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Quantum well & Semiconductor laser theory. The author has an hindex of 10, co-authored 14 publications receiving 291 citations.
Papers
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TL;DR: The first successful operation of InGaAs strained layer quantum well (Sl-QW) injection laser at about 2 microns was reported in this article, where the threshold current density and the external differential quantum efficiency of 5 microns wide and 800 microns long ridge waveguide laser were 25 kA/sq cm and 6 percent, respectively.
Abstract: The first successful operation of InGaAs strained layer quantum well (Sl-QW) injection lasers at about 2 microns is reported The threshold current density and the external differential quantum efficiency of 5 microns wide and 800 microns long ridge waveguide lasers were 25 kA/sq cm and 6 percent, respectively The devices had a reverse leakage current of less than 20 micro-A at -1 V indicating epitaxial layers with low defect density
77 citations
TL;DR: The overall magnitude of the observed absorption is explained correctly by the theory, with both free-carrier (indirect) and inter-valence-band (direct) transitions contributing significantly to the total absorption.
Abstract: Optical absorption in p-type GaAs with hole concentrations between 10 exp 19 and 10 exp 20/cu cm has been measured for wavelengths between 2 and 20 microns and compared with results of theoretical calculations. In contrast to previous measurements at lower doping levels, the occupied hole states are far from the zone center, where the heavy- and light-hole bands become parallel. This gives rise to a large joint density of states for optical transitions. It is found that the overall magnitude of the observed absorption is explained correctly by the theory, with both the free-carrier (indirect) and the inter-valence-band (direct) transitions contributing significantly to the total absorption. The strength of the absorption (a about 20,000/cm for N(A) = 5 x 10 exp 19/cu cm) is attractive for long-wavelength infrared-detector applications.
41 citations
TL;DR: In this paper, the spectral and temporal response of AlGaAs/GaAs p-i-n photodetectors with superlattice intrinsic regions grown by molecular beam epitaxy are reported.
Abstract: Measurements of the spectral and the temporal response of AlGaAs/GaAs p-i-n photodetectors with superlattice intrinsic regions grown by molecular beam epitaxy are reported. The feasibility for high-speed applications is demonstrated by a time constant limited impulse response of 200 ps (full width at half-maximum) when excited near the band edge with 100 ps optical pulses. The theory-predicted and recently verified voltage tunability of the band edge with clearly resolved excitonic resonances was observed. The responsivity was measured to be 0.2 A/W.
29 citations
TL;DR: In this paper, a strain-induced reduction of the valence-band nonparabolicity and density of states was investigated for In(0.2)Ga(0,0.8)As/GaAs/AlGaAs single quantum well laser, emitting at 980 nm, have been grown by molecular beam epitaxy.
Abstract: Low threshold current density strained-layer In(0.2)Ga(0.8)As/GaAs/AlGaAs single quantum well lasers, emitting at 980 nm, have been grown by molecular beam epitaxy. Contrary to what has been reported for broad-area lasers with pseudomorphic InGaAs active layers grown by metalorganic chemical vapor deposition, these layers exhibit a high internal quantum efficiency (about 90 percent). The maximum external differential quantum efficiency is 70 percent, limited by an anomalously high internal loss possibly caused by a large lateral spreading of the optical mode. In addition, experimental results supporting the theoretically predicted strain-induced reduction of the valence-band nonparabolicity and density of states are presented.
25 citations
TL;DR: In this article, a periodically delta-doped InGaAs/GaAs multiple quantum well structure with an excitation intensity of 100 mW/sq cm and an absolute quantum well absorption change of more than 9000 cm was measured corresponding to a differential absorption change as high as 58 percent at the excitonic resonance.
Abstract: Strong optically induced absorption modulation has been achieved in a periodically delta-doped InGaAs/GaAs multiple quantum well structure. The use of delta-doping has enabled efficient modulation in short-period structures using a low-power semiconductor laser. With an excitation intensity of 100 mW/sq cm an absolute quantum well absorption change of more than 9000 cm has been measured corresponding to a differential absorption change as high as 58 percent at the excitonic resonance.
22 citations
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TL;DR: In this paper, the experimental and theoretical investigations of the linear and nonlinear optical properties of semiconductor quantum well structures, including the effects of electrostatic fields, extrinsic carriers and real or virtual photocarriers, are reviewed.
Abstract: In this article we review the experimental and theoretical investigations of the linear and nonlinear optical properties of semiconductor quantum well structures, including the effects of electrostatic fields, extrinsic carriers and real or virtual photocarriers.
791 citations
TL;DR: In this article, the authors discuss a number of theoretical and experimental issues in quantum well lasers with emphasis on the basic behavior of the gain, the field spectrum, and the modulation dynamics and reveal that the use of quantum well structures results in improvement of these properties and brings several new concepts to optical semiconductor devices.
Abstract: We discuss a number of theoretical and experimental issues in quantum well lasers with emphasis on the basic behavior of the gain, the field spectrum, and the modulation dynamics It is revealed that the use of quantum well structures results in improvement of these properties and brings several new concepts to optical semiconductor devices
534 citations
TL;DR: In this article, a review of the last few years in this field and some future directions is presented. But the authors do not discuss the use of MQW's in optical modulators.
Abstract: Because the electroabsorption effect in semiconductor multiple quantum well material is approximately 50 times larger than in bulk semiconductors, significant interest has been generated in the use of MQW's in optical modulators Small high-speed devices have been made which show promise for external modulators in optical transmission systems, as well as for encoding and processing components in optical interconnect and signal processing systems The fact that these modulators are made from III-V semiconductors had led to interest in integration of these components with other active optoelectronic components Although most devices have operated with light of a wavelength of 085 mu m, recently much progress has been made in applying this technology to devices operating near 155 mu m The author reviews the work of the last few years in this field and indicates some future directions >
268 citations
TL;DR: A review of nonlinear optics in semiconductors can be found in this article, where the focus is on nonlinear absorption and the refractive index that arises from the photo-induced excitation of free carriers.
Abstract: Semiconductors provide some of the most promising materials for nonlinear optics, because of large resonant nonlinearities, control of recombination time (from milliseconds to femtoseconds), well-developed fabrication technologies, and compatibility with other optoelectronic devices. The paper reviews some of the concepts and results that have come from the study of nonlinear optics in semiconductors. The emphasis is on nonlinear absorption and the refractive index that arises from the photo-induced excitation of free carriers. Mechanisms described include state-filling, carrier transport, and photorefractivity. Devices include optical bistability, reflective asymmetric Fabry-Perot all-optical absorptive switches, optically addressed spatial light modulators, and real-time holography. The paper's approach is to provide a basic engineering understanding of the principles, some of the historical details, and a snapshot of the state of the field today.
251 citations
TL;DR: In this paper, the progress in longwavelength compressively and tensile-strained InGaAs(P) quantum-well semiconductor lasers and amplifiers is reviewed.
Abstract: The progress in long-wavelength compressively and tensile-strained InGaAs(P) quantum-well semiconductor lasers and amplifiers is reviewed. By the application of grown-in strain, the device performance is considerably improved such that conventional bulk and unstrained quantum-well active-layer devices are outperformed, while a high reliability is maintained. >
187 citations