Bloch-function analysis of resonant arrays of antiguided diode lasers

Bloch-function analysis of antiguided laser arrays provides closed-form expressions for key parameters in array design, and allows new insights in device behavior. For resonant and near-resonant devices it is found that as the gain is preferentially placed in the low-index regions (i.e., antiguide cores) the array mode favored to lase is the resonant leaky mode: in-phase or out-of-phase type. The intermodal discrimination is found to be strongly asymmetrical with respect to resonance: the resonant mode is preferred to lase over a much wider range in index step, Δn, variation on the high-Δn side of resonance than on the low-Δn side of resonance. Devices with Talbot-type spatial filters invariably operate in-phase except for Δn values well below resonance, when out-of-phase-like modes take over.