Transverse structures of the optical field: generation and control in broad-area lasers. Part 2. Vertical-cavity surface-emitting laser

We report a comprehensive study of the spatiotemporal dynamics of miniature, broad-area, vertical-cavity surface-emitting lasers (VCSELs). The main attention is paid to the development of methods for stabilizing their output using external optical injection. A detailed analysis demonstrates that free-running VCSELs exhibit chaotic dynamics caused by modulation instability. This leads to beam filamentation and a significant deterioration in its spatiotemporal characteristics. An improved mathematical model is considered that takes into account key features of semiconductor active media, including the Henry factor, which allows the observed nonlinear effects to be adequately described. It is found that external optical control not only effectively suppresses the development of instabilities but also ensures the formation of controllable spatial structures. In particular, the possibility of generating regular patterns (stripe, ring, and hexagonal structures) and controlled switching between them is demonstrated. The obtained results are important for the development of stable compact laser systems for applications in photonics, optical information processing, and communication systems, where precise control of the spatial characteristics of radiation is needed.