Self-aligned AlInAs native oxidized buried hetero-structure InGaAsP/InP distributed feedback laser with circular beam and high T/sub 0/ potential

InGaAsP/InP self-aligned native oxidized buried heterostructure distributed feedback (SA-NOBH-DFB) laser is proposed. It is easy to process as ridge waveguide DFB laser and has a superior performance. The current aperture can be easily controlled without selective regrowth. Preliminarily, the laser exhibited a low threshold of 5.0 mA with 36 dB side mode suppression ratio (SMSR) at 1.562 /spl mu/m. It shows a single transverse mode with full width at half maximum angles of 33.6/spl deg/ and 42.6/spl deg/ for the lateral and vertical fields, respectively. Its beam is move circular than that of the as-grown BH laser because the refractive index of oxide is lower than as-grown layer and results in larger lateral optical confinement. Its characteristic temperature (T/sub 0/) is 50 K in average but it even becomes higher in high temperature region.