Chaos from a free-running broad-area VCSEL

We experimentally report on the detection of chaos from a free-running commercial broad-area vertical-cavity surface-emitting laser (VCSEL) without the need for external perturbation such as optical feedback, injection, or current modulation. The evolution of nonlinear dynamics leading to chaotic behavior is studied, and the system's complexity is characterized using chaos titration and correlation dimension. We link the occurrence of chaos with the complex interplay between the spatial laser mode competition and polarization dynamics.