Diffraction-limited far-field pattern from an uncoupled AlGaAs laser array using high-efficiency diffractive microlenses.

A novel technique is presented which uses an array of high-efficiency diffractive microlenses to expand the individual laser beams and uses diffractive coupling in an external cavity to provide the necesssary mutual coherence. The technique is applicable to both 1- and 2-D laser arrays. Experimental results are presented for a 1-D laser array consisting of seven gain-guided multiple-quantum-well lasers.