0° phase mode operation in phased-array laser diode with symmetrically branching waveguide

Abstract

An AlGaAs phased-array laser with a novel index waveguide structure like the letter ‘‘Y’’ is described. In all arrays with such a structure, controllable selection of only 0° phase mode and complete suppression of 180° phase shift mode is achieved up to ∼65 mW in 2%–96% coated devices. The far-field patterns, near-field patterns, and spectra of the array are in good agreement with the theoretical results. The cw threshold currents are ∼100 mA, and the external differential quantum efficiencies are 57% per facet.