Analysis and performance of channeled-substrate-planar double-heterojunction lasers with geometrical asymmetries

The effects of geometrical asymmetries on the optoelectronic properties of CSP-DH lasers using self-consistent calculations of the optical field and the electron-hole distribution in the active layer are analyzed and compared with device measurements. Laser properties modeled include gain profile, threshold, slope efficiency, near field, and far field. This analysis shows that small geometrical asymmetries due to device fabrication can produce significant changes in the optical and electrical properties of CSP-DH lasers, especially at high-output power levels. For example, a 0.5 μm misalignment of the Zn diffusion with respect to the substrate channel can produce lateral near-field and far-field shifts of 0.6 μm and 2.5°, respectively, and limit single spatial mode operation to about 30 mW.