High Efficiency Oxide-Confined High-Index-Contrast Broad-Area Lasers with Reduced Threshold Current Density and Improved Near-Field Profile

We have recently developed a simple, self-aligned ridge waveguide laser fabrication process for high-performance GaAs-based narrow-stripe devices. A high-index-contrast (HIC) structure is formed by deep etching (through the waveguide core layer), followed by non-selective O₂-enhanced wet thermal oxidation to grow a uniform thickness layer of high-quality native oxide (200-300 nm) at the sidewalls of the etch-exposed high Al-composition cladding layers and low Al-composition core layer and active region. All devices in this work are fabricated in an 808 nm single quantum well graded-index separate-confinement heterostructure (GRINSCH) with no facet coating or heatsinking employed, and are tested p-side up with 1% duty cycle current pulses at room temperature. Conventional weak index-guided broad-area devices are also made from the same material to comparatively study the benefit of good lateral electrical and optical confinement in our HIC oxide-confined devices.