Monte Carlo modeling of the dual-mode regime in quantum-well and quantum-dot semiconductor lasers

Abstract

Monte Carlo markovian models of a dual-mode semiconductor laser with quantum well (QW) or quantum dot (QD) active regions are proposed. Accounting for carriers and photons as particles that may exchange energy in the course of time allows an ab initio description of laser dynamics such as the mode competition and intrinsic laser noise. We used these models to evaluate the stability of the dual-mode regime when laser characteristics are varied: mode gains and losses, non-radiative recombination rates, intraband relaxation time, capture time in QD, transfer of excitation between QD via the wetting layer... As a major result, a possible steady-state dual-mode regime is predicted for specially designed QD semiconductor lasers thereby acting as a CW microwave or terahertz-beating source whereas it does not occur for QW lasers.

Markov model of quantum fluctuations at the transition to lasing of semiconductor nanolasers

“…We will first concentrate on the cross-validation of the CMM versus the MMM, which was already used to predict ultimate noise performances of SC lasers [12] or the stability of a two-mode regime [23]. Second we will use the CMM to question the threshold definition in nanolasers already addressed by many authors [10,11,20,29].…”

“…Although it was shown to give excellent band description [24], it is unpractical here because either photonic events or thermalization events within CB or VB modify energy. That is why we are moving from such a microcanonical model to a microscopic Markov model (MMM) [12,23], which adds the possibility for an electron to downgrade its energy with a rate p and upgrade it with the same rate multiplied by the Boltzmann factor. This produces a correct electron repartition within bands and consequently on CBLL and VBLL.…”

“…The model proposed in this document falls within the latter framework and considers microlasers with QW active medium. It takes into account the semiconductor electronic band description [12,23] and finely reproduces the carrier-carrier interactions within conduction and valence bands. This is obtained owing to an evenly-spaced representation of energy levels within bands that was shown separately in perfect agreement with the grand-canonical density of states expected in semiconductors [24].…”

“…Although satisfactory from the point of view of accuracy, this model suffers from its lack of numerical efficiency if too many electrons have to be simulated in each band due to their thermalization. Extending results of [12,23] to more realistic nanolasers operating at room temperature would thus have required excessive CPU time. In the present paper we use a known principle on the Markov chains [25,26] to split our birth-death process into a thermalization part and a photonic events part to speed up the simulation process.…”

Stochastic Simulator for modeling the transition to lasing

“…We can distinguish two classes of stochastic models: 1. those which describe the evolution of the ensemble, either predicting the static features or their statistical dynamics, and 2. those which predict the detailed dynamics. To the first class belong Monte-Carlo simulations, which have been recently applied to lasers with success [5], and Fokker-Planck models which have a long history in laser physics [6]. The Master Equation clearly belongs to the second class, since it allows for detailed predictions of the dynamical evolution of the system, but its use becomes unwieldy when the number of elements (modes of the e.m. field) exceeds a few units.…”