Supermode discrimination in diffraction-coupled laser arrays with separate contacts

We show that in-phase lasing is favored in diffraction-coupled arrays with separate electrical contacts for the common unguided diffraction zone and for the waveguide section, if the common unguided section is biased above a critical level. Below that level, out-of-phase lasing will be favored. By varying the current about the critical level, the far-field intensity switches from a wide far-field pattern characterized by the admixture of several supermodes, to a near-diffraction-limited single peak.