Influence of Indium-Percentage Variation on Dynamical Characteristics of InxGa1-xAs/GaAs(001) Quantum Dot Lasers

TL;DR

This study examines how varying indium content affects the dynamical behavior of InxGa1-xAs/GaAs quantum dot lasers, revealing specific impacts on energy levels, modulation bandwidth, and laser delays, with an optimized cavity length identified.

Contribution

It introduces a detailed analysis of indium percentage effects on quantum dot laser dynamics using a three-level model and numerical rate equations, highlighting new dependencies and optimization strategies.

Findings

Increased indium reduces energy gap and electron-hole recombination energy.

Lasing sensitivity to indium percentage affects delay times and modulation bandwidth.

Certain laser parameters like threshold current remain unaffected by indium variation.

Abstract

The influence of indium percentage on dynamical characteristics of InxGa1-xAs/GaAs(001) quantum dot lasers (QDLs) is investigated. Energy levels of self-organized truncated-cone-shape QDs are calculated by means of the eight-band k.p model, and their dependence to indium percentage is surveyed. Then, by presenting a three-level model and numerical solution of the resulting rate equations, laser properties are determined. Our results show that inclusion of more indium gives rise in the reduced energy gap and electron-hole recombination energy. Moreover, lasing process for both Ground State (GS) and Excited States (ES) sound to be sensitive to indium percentage. It is shown that rise of indium percentage at fixed injected current results in the increased ES turn-on delay and GS photon number and 3dB modulation bandwidth, and decreased ES photon number, GS turn on delay, amplitude of relaxation oscillations, output power, and ES 3dB modulation bandwidth; but has no effect on threshold current and laser gain. At last, we find an optimized cavity length which was likely to be independent of indium percentage. Keywords: QD lasers; Engineering energy levels; Small signal modulation; Nanocrystalline materials; Indium component