Transition between turbulent regimes in a forced semiconductor laser

The question of the formation of spatiotemporal patterns in nonlinear systems is a subject of many research activities in different out of equilibrium systems [1]. Recently, in nonlinear optics, the formation of spatiotemporal structures and their statistical properties have been studied in the context of integrable turbulence [2]. In the opposite in non-integrable systems, the transition between a stable coherent laminar state and a highly disordered state has been demonstrated in fibre laser [3]. Recently, the impact of defect mediated turbulence on the statistical properties of a laser field has been pointed out in the context of optical rogue waves [4]. In spite of the recent experimental and theoretical demonstrations of the coexistence between coherent structures as dissipative phase solitons and turbulent state in forced semiconductor laser [5], no comparative studies of the field properties in phase and defect mediated turbulence regimes have been reported yet. Here we present an experimental observation of the transition between different turbulent behaviors of a strongly multimode semiconductor laser with external optical forcing. We resolve the optical phase and characterize the formation of defects in relation to the statistical properties of the field.