Chaos in Solitary VCSELs: Exploring the Parameter Space With Advanced Sampling

We explore the parameter space of the so-called spin-flip model by advanced sampling techniques to analyze the requirements leading to polarization chaos in solitary vertical-cavity surface-emitting lasers. We first investigate the performances of different sampling techniques for multidimensional parameter space exploration. Purely random sampling and tensor-product grids require a large amount of samples to uniformly cover the whole space, and we show that other schemes are highly superior to this regard, hence allowing a reduced number of samples and computation to be used to reach the same level of insight in the system behavior. Considering the scarcity of the chaotic regions and their sharp boundaries, combined with quite involved computations to identify chaotic dynamics, the proposed approach is shown to be highly beneficial. Here, we are able to highlight two thresholds limiting the range of injection current for which chaos can be observed, and to link them to a fine balance between the spin relaxation rate and the birefringence.