Analysis and design of phase-coupled laser arrays

Coupled-mode theory is employed for the analysis and, consequently, for the design of phase-coupled laser arrays that may have improved properties, such as better supermodes discrimination and a narrower far-field pattern. We start with a brief description of the improved coupled-mode formulation for multiwaveguide systems. The formulation encompasses real and imaginary index perturbations, which determine modal gains or losses. We proceed by presenting the analysis of various phase-coupled, index-guided laser arrays. A common problem in many cases is poor mode discrimination, which may result in excitation of several lateral supermodes and wider far-field patterns. Based on the improved coupled-mode theory, some new promising structures are presented, along with a few numerical examples which suggest a better mode discrimination between the lowest-order and higher-order lateral modes.