Nonlinear dynamics and synchronization of an array of single mode laser diodes in external cavity subject to current modulation

We study the dynamics of an array of single mode laser diodes subject to filtered feedback provided by an external reflection grating. Our numerical simulations show that by modulating the injection current the array can be phase synchronized leading to high power coherent emission. The output peak power density can be varied by tuning the modulation frequency and can be resonantly enhanced once the frequency matches the inverse of external cavity round trip time and mode-locking behavior is realized. Both non-resonant and resonant injection current modulation results in an excellent degree of phase synchronization and coherence at certain modulation amplitudes and frequencies that is manifested by coherent enhancement of far-field optical intensity.