AM and FM mode-locking dynamics in a semiconductor quantum-dot laser.

This paper describes the progression from free-running to FM and AM mode locking in a semiconductor laser. Experiments on quantum-dot lasers, supported by analyses based on multimode semiclassical laser theory, indicate AM and FM mode locking as two manifestations of the frequency locking phenomenon. Free-running corresponds to unlocked, FM corresponds to partially locked, and AM corresponds to locked dynamical regimes of coupled nonlinear oscillators. Reduction of the microscopic semiclassical laser equations to Adler's equation provides insight by connecting FM behavior to the rich dynamics exhibited by partial locking, including bifurcation, coherence collapse, and chaos.