Optimization of Combined Coherent Gain-Switch Pulsing in a Large Array of Semiconductor Lasers

We combine gain switching and external optical feedback to achieve high-power coherent pulsing in a large array of semiconductor lasers. The simulations are performed in the framework of the Lang-Kobayashi model with modulation of the electrical bias. Long-range coupling in the network of emitters and precise tuning of the modulation frequency are key parameters to obtain both phase-locking between the emitters, and reproducible, periodic, high intensity bursts, i.e. robust, coherent pulsing. The configuration we present here relies on non-filtered conventional optical feedback and allows achieving phase-locked pulsing across the array, including at modulation frequencies that are resonant and not resonant with the external cavity frequency and its harmonics. This work impacts on the realization of phase-synchronized pulsed sources from semiconductor laser arrays and provides insight for the generation of complex nonlinear dynamics in large networks of oscillators.