Channeled substrate nonplanar laser analysis - Part I: Formulation and the plano-convex waveguide laser

An analysis of diode lasers with lateral thickness variations in the active and/or guiding layers is presented. The technique, which applies both at and above threshold, models the current flow from the stripe contact, the charge diffusion within the active region, the modal wave propagation, and the cavity condition, self-consistently, such that the phenomena of spatial hole burning in the charge distribution by the modal intensity and the changes in the complex refractive index produced by the charges are accounted for simultaneously. Results are obtained for threshold current as well as laser behavior above threshold, including the charge density distribution, the mode patterns, the differential quantum efficiency, and the lowest order mode power at which the laser begins oscillating in more than one spatial transverse mode. A study of the piano-convex waveguide laser is described in detail and an Appendix discussing the mathematical methods is included.