Laser source with submicron aperture

A buried heterostructure (NBH) laser diode that has a narrow emission aperture for use in an optical pickup head with high aluminum content layers formed adjacent to and on opposite sides of the active region and thereafter etching vertical trenches on either side of the active region forming the narrow emission aperture, oxidizing the exposed side edges of the high aluminum content layers to form a high index difference between these layers and the active region so as to confine the mode very tightly in orthogonal directions, creating an emission aperture spot size less than 1 μm in either orthogonal direction.

A buried heterostructure (NBH) laser diode source comprising a narrow emission aperture for use in an optical pickup head, an oxidizing source formed in the laser diode source adjacent to its active region to form a stable low refractive index oxide upon oxidation, the oxidation providing for additional limited optical confinement of the narrow emission aperture.

A buried heterostructure (NBH) laser source comprising:

• a nonplanar substrate having a mesa on said substrate;
• a plurality of epitaxial layers formed on said nonplanar substrate such that an active region is formed on a top surface of said mesa surrounded by epitaxial layers of lower refractive index than said active region, said active region providing a waveguide cavity for propagation of a single fundamental mode;
• said mesa having a top surface and adjacent sidewalls such that in the growth of said epitaxial layers above said active region doped with a first conductivity type, said above active region epitaxial layers depositing on said top surface as said first conductivity type and depositing on said sidewalls as a second conductivity type.