LOW-LOSS BRAGG-REFLECTOR LATERAL-TRANSVERSE-MODE CONFINEMENT IN ALGAINP RED LASER

A low-loss Bragg-reflector-waveguide (BRW) structure is proposed for AlGaInP red lasers. This BRW laser uses (AlGaInP/GaAs)n Bragg-reflector (BR) block layers in place of conventional GaAs blocl layers. Propagating-mode calculations reveal that an aluminum content (x) lower than 0.2 for (AlxGa1-x)0.5In0.5P in the BR block layers is sufficient for reducing mode loss together with confining the lateral transverse mode. Mode loss in the (AlGaInP/GaAs)n BR region is reduced resonantly to one-third that of a conventional GaAs block region. This reduction originates from a combination of Bragg reflection and the low absorption loss in the AlGaInP crystal. The refractive-index step, formed at the edge of a ridge stripe by the BR block layers, is around 1 x 10(-2).