Dynamics of semiconductor passively mode-locked lasers: Experiment and theory

This work presents an overview of a combined experimental and theoretical analysis on passive mode-locking in semiconductor quantum-well lasers based on reverse biased saturable absorbers. The experimental results describe the dynamics of laser diodes based on Aluminum quaternary materials at 1550 nm and we will also mention recent results related to GaAs Lasers at 830 nm. The experimental facts evidenced the important impact of the dispersion in frequency domain of the saturable absorption as well as the relevance of the dynamical detuning between the gain peak of the amplifying sections and the edge of absorption of the saturable absorber. Reproducing the dispersion of the saturable absorption demanded an important effort on our modeling approach, specially regarding the development of an efficient but reasonably accurate method to describe in time domain the response of the semiconductor material. The successful realization of this endeavor resulted in the development of the free software simulation package FreeTWM that allows to simulate a large class of multi-section devices. I will discuss how our modeling approach reproduces and explains the experimental results. I will conclude on a discussion of the possible improvements to FreeTWM as for instance the consideration of the ultrafast non linearities e.g. the so-called spectral hole burning and carrier heating effects.