Reactive-ion-etched diffraction-limited unstable resonator semiconductor lasers

We present characterization and analysis of wide-stripe unstable resonator semiconductor lasers with reactive-ion-etched facets. The mirror facets have rms roughnesses of only 3-5 nm. Laser beam quality and brightness performance are measured in terms of resonator structure and fabrication parameters. Lateral M(2) values as low as 1.25 at five times threshold are found, This data is compared to that derived from a Huygen's integral-beam propagation method simulation which includes appropriate physical and process-induced aberrations, and good agreement is found.