Surface-grating distributed bragg reflector quantum-well lasers fabricated in AlGaAs-GaAs asymmetric epitaxial...

Ridge waveguide lasers, integrated with single deep-surface distributed Bragg reflectors (DBR's) in the passive section, were fabricated with a GaAs-AlGaAs double-quantum-well structure in an asymmetric waveguide. Third-order gratings, with a period of 389 nm and defined by holographic lithography, were formed by low-damage reactive ion etching processes. The grating losses and optical coupling coefficients were estimated, in particular, by use of the relationship between the real and the effective grating lengths that were computed and reexamined by measurements of grating periodicity and mode spacing. By use of two different geometries, we produced guide lines for obtaining high-performance lasing properties for these surface-grating DBR lasers. Additionally, a detailed analysis of lasing wavelength shifts was carried out for this study. It was found that injected-carrier-induced effects shift the lasing wavelength much more than gain-loss competition within an extended DBR laser cavity.