High-speed modulation and switching characteristics of In(Ga)As-Al(Ga)As self-organized quantum-dot lasers

Bhattacharya, P.; Klotzkin, D.; Qasaimeh, O.; Zhou, Wei; Krishna, S.; Zhu, Dahuan

doi:10.1109/2944.865098

Cited by 87 publications

(44 citation statements)

References 74 publications

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“…3 is comparable to the maximum bandwidths of 5-6 GHz reported so far for directly modulated QD lasers [5]. The slow gain recovery, illustrated above, is expected to limit both lasers and amplifiers.…”

Section: Modelsupporting

confidence: 56%

“…High differential gain has proved to be present in many QD devices [2], [3] and, recently, ultrafast gain recovery on the scale of 100 fs has been demonstrated [4]. Despite these unique features, the maximum modulation frequency of present day QD lasers at room temperature is only 5-6 GHz [5], which is slower than bulk and QW devices. Here, we will analyze the gain recovery mechanisms of QD devices based on a comprehensive numerical model and, on this basis, give a possible explanation for the problems in realizing ultrafast QD devices.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast gain recovery and modulation limitations in self-assembled quantum-dot devices

Berg

Bischoff

Magnúsdóttir

et al. 2001

IEEE Photon. Technol. Lett.

221

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. Ultrafast gain recovery and modulation limitations in self-assembled quantum-dot devices. I E E E Photonics Technology Letters, 13(6) Abstract-Measurements of ultrafast gain recovery in self-assembled InAs quantum-dot (QD) amplifiers are explained by a comprehensive numerical model. The QD excited state carriers are found to act as a reservoir for the optically active ground state carriers resulting in an ultrafast gain recovery as long as the excited state is well populated. However, when pulses are injected into the device at high-repetition frequencies, the response of a QD amplifier is found to be limited by the wetting-layer dynamics.Index Terms-Gain recovery, quantum-dot amplifiers, ultrafast.

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Section: Modelsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Ultrafast gain recovery and modulation limitations in self-assembled quantum-dot devices

Berg

Bischoff

Magnúsdóttir

et al. 2001

IEEE Photon. Technol. Lett.

221

View full text Add to dashboard Cite

show abstract

“…The "capture time" is inversely proportional to the 3-D density of unoccupied states in the QD ensemble . Both and [see (11) and (15) ] depend crucially on the structure parameters. For this reason, and thus defined are not the true time constants describing the respective processes [in contrast to , which is independent of the carrier density-see (34)].…”

Section: ) "Capture Time" Into the Qd Ensemblementioning

confidence: 99%

Internal efficiency of semiconductor lasers with a quantum-confined active region

Asryan

Luryi

Suris

2003

IEEE J. Quantum Electron.

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Abstract-We discuss in detail a new mechanism of nonlinearity of the light-current characteristic (LCC) in heterostructure lasers with reduced-dimensionality active regions, such as quantum wells (QWs), quantum wires (QWRs), and quantum dots (QDs). It arises from: 1) noninstantaneous carrier capture into the quantum-confined active region and 2) nonlinear (in the carrier density) recombination rate outside the active region. Because of 1), the carrier density outside the active region rises with injection current, even above threshold, and because of 2), the useful fraction of current (that ends up as output light) decreases. We derive a universal closed-form expression for the internal differential quantum efficiency int that holds true for QD, QWR, and QW lasers. This expression directly relates the power and threshold characteristics. The key parameter, controlling int and limiting both the output power and the LCC linearity, is the ratio of the threshold values of the recombination current outside the active region to the carrier capture current into the active region. Analysis of the LCC shape is shown to provide a method for revealing the dominant recombination channel outside the active region. A critical dependence of the power characteristics on the laser structure parameters is revealed. While the new mechanism and our formal expressions describing it are universal, we illustrate it by detailed exemplary calculations specific to QD lasers. These calculations suggest a clear path for improvement of their power characteristics. In properly optimized QD lasers, the LCC is linear and the internal quantum efficiency is close to unity up to very high injection-current densities (15 kA/cm 2 ). Output powers in excess of 10 W at int higher than 95% are shown to be attainable in broad-area devices. Our results indicate that QD lasers may possess an advantage for high-power applications.Index Terms-Quantum dots (QDs), quantum wells (QWs), quantum wires (QWRs), semiconductor heterojunctions, semiconductor lasers.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] In Refs. [19][20][21], the lightcurrent characteristic (LCC) of semiconductor lasers (the optical power as a function of the pump current) was calculated considering only direct capture of carriers from the optical confinement layer (OCL) into the lasing state in a quantum-confined active region.…”

Section: Introductionmentioning

confidence: 99%

Direct and indirect capture of carriers into the lasing ground state and the light-current characteristic of quantum dot lasers

Asryan

2014

Journal of Applied Physics

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Articles you may be interested inEffect of excited states on the ground-state modulation bandwidth in quantum dot lasers Appl. Phys. Lett. 102, 191102 (2013) We calculate the light-current characteristic (LCC) of a quantum dot (QD) laser under the conditions of both direct and indirect capture of carriers from the optical confinement layer into the lasing ground state in QDs. We show that direct capture is a dominant process determining the ground-state LCC. Only when direct capture is slow, the role of indirect capture (capture into the QD excited state and subsequent intradot relaxation to the ground state) becomes important. V C 2014 AIP Publishing LLC.

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High-speed modulation and switching characteristics of In(Ga)As-Al(Ga)As self-organized quantum-dot lasers

Cited by 87 publications

References 74 publications

Ultrafast gain recovery and modulation limitations in self-assembled quantum-dot devices

Ultrafast gain recovery and modulation limitations in self-assembled quantum-dot devices

Internal efficiency of semiconductor lasers with a quantum-confined active region

Direct and indirect capture of carriers into the lasing ground state and the light-current characteristic of quantum dot lasers

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