Alternative formulation of carrier transport in spatially-dependent laser rate equations

• Published in: Optical and quantum electronics 2004-08, Vol.36 (10), p.881-891
• Main Authors: JUNGO, M, ERNI, D, BAECHTOLD, W
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Lasers; Optics; Physics; Semiconductor lasers; laser diodes
• ISSN: 0306-8919; 1572-817X
• DOI: 10.1007/s11082-004-4955-6

The level of accuracy of the conventional implementation of carrier transport into the quantum wells in spatially-dependent rate equations appears too high compared to the overall precision of rate equations. The dynamic description of the normalized carrier profile in the barrier region is of little use, since no stimulated interactions with the optical field occur in this region. Furthermore, it is only described by transverse diffusion and effects such as transport through the graded heterostructures formed by the mirror layers are neglected, which makes its accuracy disputable. Finally, this implementation nearly doubles the time required to solve the carrier rate equations. We propose therefore a more consistent model that still considers the dynamic evolution of the carrier population while assuming a time-invariant profile at the interface between the barrier and the quantum wells. This simplification both removes the requirement for unavailable parameters (such as the ambipolar diffusion coefficient in the barrier) and improves the numerical efficiency of the algorithm since only one additional ordinary differential equation needs be solved. The model is still capable of reproducing the influence of longitudinal transport on the modal distribution and high-frequency behavior of diode lasers.