In this paper

we report the manufacture and characteristics of buried twin-ridge substrate large optical cavity structure GaAIAs/GaAs laser (BTRS-LOC). This laser has following features.(1) Thethinner active layer(~0.1μm) can be grown by Using LPE on the twin-ridge substrate. The optical power confinement factor will become smaller

so the large spot size of near-field pattern at facets can be obtained. (2) The spot size of the near-field pattern is further enlarged by the LOC structure. (3) The current confinement to the stripe is realized by a reverse-biased heterojunction of

n

-GaAs (current blocking layer) and

p

-GaAlAs (first cladding layer). (4) The transverse mode is confined by the built-in refractive index difference which is caused by the fact that outside the channeled region

the evanescent tails of lasing light reach the current blocking layer.