Analysis of phase locking in diffraction-coupled arrays of semiconductor lasers with gain/index coupling

We develop an analytical model of the phase-locking mechanism for diffraction-coupled arrays of semiconductor lasers. While the phase-locking range is found to be limited by nonuniformities between the individual lasers, increasing the gain-index coupling can expand this range. Detailed computer simulations confirm these predictions. Recommendations are made for using arrays of surface-emitting lasers to improve the stability of phase locking.