Very low-threshold separate-confinement-heterostructure lasers prepared by liquid phase epitaxy

Abstract
AlGaAs separate‐confinement‐heterostructure lasers with low threshold current density (lowest averaged Jth of 317 A cm2) are reproducibly prepared by liquid phase epitaxy. All optical‐cavity layers of the lasers are undoped and their compositions are not graded. The low threshold is attained by increased internal efficiency resulting from effective injection of electrons into the active layer in the thin cavity, as well as by low internal loss of the optical cavity.