Single-Facet Teardrop Laser With Matched-Bends Design

The matched-bends criterion, a method for effectively reducing the straight-bend-straight transition loss in planar optical waveguides, is applied to design a single-facet teardrop laser utilizing an on-chip loop mirror reflector. Simulations of a matched-bends teardrop reflector show a great improvement in power reflectance (97%) over unmatched-bends designs (10%). The teardrop laser is fabricated by deep etching and nonselective sidewall oxidation of an 808-nm AlGaAs/InAlGaAs/GaAs heterostructure. The resulting high-index-contrast ridge-waveguide laser exhibits a low-threshold current of 43 mA, a high slope efficiency of 0.465 W/A, and a single spectral lasing mode with a side-mode suppression ratio of 24 dB. Simulations are presented to demonstrate that the matched-bends design can be scaled geometrically to reduce the area occupied by the teardrop bend reflector by a factor of 677.