Processes have been developed for producing stripe-geometry planar DH lasers and channeled substrate buried DH lasers where lateral-current confinement is obtained with reverse-biased n-p junctions on both sides of the active layer. These current-confinement schemes lead to current flow only through the two superimposed top and bottom stripe windows in otherwise completely reverse-biased n-p junctions. The structures are composed only of as-grown liquid-phase-epitaxy multilayers. These lasers have low threshold current densities, clean stable optical-mode patterns, and excellent linearity in the light-current curves. In addition, the channeled substrate buried DH lasers have optical and carrier confinement in both transverse directions, while also achieving efficient lateral-injection-current confinement. Results from a theoretical analysis, which describes the dependence of the threshold current density Jsth of DH lasers upon stripe width S, are compared to the measured dependence and excellent agreement is obtained.