Monte Carlo Simulation of Laser Diodes Sub-Poissonian Light Generation

TL;DR

This paper introduces a Monte Carlo simulation method for laser diodes that accurately models sub-Poissonian light generation, revealing new effects at high power levels and improving understanding of laser noise characteristics.

Contribution

The paper presents a detailed Monte Carlo simulation capturing electron, hole, and photon dynamics in laser diodes, including effects at high power levels not well described by existing theory.

Findings

Simulation reproduces known noise theory results under good thermal contact.

At high power, spectral-hole burning and temperature fluctuations reduce sub-Poissonian noise.

The spectral density of photo-current narrows with increasing optical power.

Abstract

When laser diodes are driven by high-impedance electrical sources the variance of the number of photo-detection events counted over large time durations is less than the average number of events (sub-Poissonian light). The paper presents a Monte Carlo simulation that keeps track of each level occupancy (0 or 1) in the conduction and valence bands, and of the number of light quanta in the optical cavity. When there is good electron-lattice thermal contact the electron and hole temperatures remain equal to that of the lattice. In that case, elementary laser-diode noise theory results are accurately reproduced by the simulation. But when the thermal contact is poor (or, almost equivalently, at high power levels) new effects occur (spectral-hole burning, temperature fluctuations, statistical fluctuations of the optical gain) that are difficult to handle theoretically. Our numerical simulation shows that the frequency domain over which the photo-current spectral density is below the shot-noise level becomes narrower as the optical power increases.