A distributed feedback ("DFB") laser featuring improved manufacturing yield and
operational characteristics is disclosed. The present DFB laser includes a bottom
confinement layer, an active region, and a top confinement layer disposed atop
an n-doped substrate. A p-doped first top layer having a first index of refraction
is disposed atop the top confinement layer. A grating is defined in the top surface
of the first top layer, and a p-doped second top layer is overlaid on the grating.
The two laser end facets are antireflectively coated. The grating is anisotropically
etched to define a low kappa grating half and a high kappa grating half. Light
waves produced in the active region interact with the grating and are biased toward
the low kappa grating half that results in the majority of light signals passing
through the end facet adjacent the low kappa grating half.