A semiconductor laser, for example a Vertical Cavity Surface Emitting Laser (VCSEL),
includes one or more photoactive layers to improve the fundamental mode operation
of lasing. The photoactive layer(s) provides on-axis current channeling, resulting
from the selective drop in resistance around the center of the photoactive layer(s)
due to photo-excitation, and counteracts "hole burning" (i.e., carrier depletion)
of the center axis region of the VCSEL cylinder. The photoactive layer(s) act as
a variable resistivity screen(s) whose radial aperture is controlled by the light
itself. The absorption of a small traction of the light intensity suffices for
significant on-axis current peaking with minimum efficiency loss and optical mode
distortion. Thus, the VCSEL has optically pumped photoactive layers that induce
significant, self-regulated, on-axis current channeling and fundamental mode stability
at high operation current, improving lasing operation. Photoactive layers may be
fabricated using molecular beam epitaxy and do not require wafer post processing.
