Dynamics and interaction of laser cavity solitons in broad-area semiconductor lasers

This chapter reviews fundamentals and dynamical properties of spatial laser cavity solitons realized in broad-area vertical-cavity surface-emitting laser (VCSEL) with frequency-selective feedback from a volume Bragg grating. The solitons are stabilized by a nonlinear frequency shift induced by the strong amplitude phase coupling in semiconductor lasers. The simplest theoretical description is by a cubic complex Ginzburg-Landau equation coupled to a linear filter. The optical phase is an additional Goldstone mode for a laser soliton. Different solitons are usually mutually incoherent due to disorder resulting from cavity length fluctuations. However, we demonstrate frequency- and phase-locking overcoming the disorder and find agreement with the archetypical Adler scenario for the phase dynamics. Fast pulsing at the round-trip frequency is found after soliton switch-on demonstrating transient mode-locking of external cavity modes. An outlook is given on the asymptotic dynamics and prospects for the spatiotemporal self-localization of light.