InGaAs-GaAs 980-nm stripe-geometry and circular ring ridge waveguide lasers fabricated with pulsed anodic oxidation

In/sub 0.22/Ga/sub 0.78/As-GaAs quantum-well stripe-geometry and circular ring lasers have been fabricated with pulsed anodic oxidation (PAO). The relationship between ridge heights and laser performance was first studied in the fabrication of stripe lasers. The lowest transparency current density (J/sub tr/) of 61.20 A/cm² was obtained from the stripe laser with a ridge height of 1.23 μm, corresponding to an etching depth where all the p-doped layers above active region were removed. With the PAO process, when the ridge height (1.77 μm) extended below the active region, J/sub tr/ is 76.03 A/cm², only increased by 24.2%. Based on the experimental results, the circular ring laser, which needs deep etching (below active region) and subsequent PAO, has been fabricated. The fabricated circular ring laser worked under continuous-wave operation at room temperature. Longitudinal mode spacing analysis clearly indicates that the ring resonator is a functional part of the whole circular ring laser.