Modeling Of Quantum-well Lasers Research Articles

Criteria for the Use of Approximations for Full Band Structures of Compound III–V Semiconductor Quantum Wells

The calculation of material gain and performance characteristics of compound III–V semiconductor quantum well (QW) lasers has been developed, incorporating various approximations for the band structure. As the accuracy and sophistication of the band structure are increased, the computational time and mathematical complexity rise accordingly. The modeling of QW lasers is examined to determine the criteria for the accurate use of a parabolic approximation for the full band structure in the calculation of the material gain and performance characteristics of a conventional III–V QW. A comparison of the cosine approximation of band structure in highly mismatched alloys is also presented.

Circuit modeling of quantum-well lasers for optoelectronic integrated circuits (ICs) including physical effect of deep-level traps

For the purposes of optoelectronic design, this paper presents a new and original small signal two-port circuit model of a quantum-well laser that has been developed from rate equations. This model is based on the physics of the spontaneous emission, stimulated emission, lightwave resonance, high-level injection, active-layer carrier degeneracy, and deep-level traps simultaneously. This model is compatible with general-purpose circuit analysis program (e.g., PSPICE) and is used to determine the frequency modulation bandwidth and the intensity modulation of the semiconductor laser. The results indicate that an increment in the density of the traps causes a decrease in both the amplitude of the output light and the bandwidth of the frequency response and an increase in the steady-state time.

Modeling of quantum-well lasers with electro-opto-thermal interaction

An equivalent circuit model has been developed for quantum-well (QW) lasers from the electrical and optical rate equations and thermal conduction equation. This model and its SPICE implementation allow self-consistent calculation of the electrical, optical, and thermal interactions using lumped elements, and make possible the simulation of multiple components in optoelectronic integrated circuits in the presence of these interactions. Physical effects which are strongly temperature dependent, such as gain variation, leakage current, and Auger recombination, have been incorporated. The model has been validated with measured laser characteristics. >

Comparison of two- and three-level rate equations in the modeling of quantum-well lasers

By explicitly including the effect of gateway states a description of the carrier transport process in quantum-well lasers is possible. These are states spatially localized to a quantum well, but which are energetically above the well and aid in the transfer of carriers from the unconfined 3-D barrier region to the 2-D well region, and vice versa. Analytical solutions for the single quantum-well case, using the ambipolar transport approximation, serve to highlight the dominant transport mechanisms in quantum-well lasers and to unify previously published two- and three-level rate equation models (Nagarajan et al, Kan et al, and Tessler et al.) in the limits of vanishingly small carrier capture and diffusion free transport across the separate confinement heterostructure (SCH) region. Although the two-level effective capture model has been successful at modeling wide SCH region quantum-well lasers, in the model developed in this work the physical mechanisms governing carrier transport (diffusion and local carrier capture) are treated separately. As a result the two-level system equations correspond to the more general model detailed here at the phenomenological level only. The implications this has on dynamical parameter estimation from measurement data are highlighted. >

Modeling of quantum-well lasers for computer-aided analysis of optoelectronic integrated circuits

A two-port circuit model for quantum-well (QW) lasers has been developed from rate equations. With emphasis on the physical principles, the phenomena of the recombination process of electron-hole pairs and the light wave resonance in the active region have been incorporated into this new model. The model has been implemented in a circuit simulator and validated with measured DC and transient laser characteristics. The frequency effects on the modulation properties of QW lasers have been studied and analyzed using a small-signal model. Simulation results show excellent agreement with experimental data. >