A vertical cavity surface emitting laser (VCSEL) is disclosed that has a
relatively low vertical resistance between the Ohmic contact to the upper
distributed Bragg reflector (DBR) and the active layer, and a structure
to substantially confine the current flow to the laser cavity so that the
VCSEL can produce a more efficient and substantially single-mode output.
In particular, the VCSEL includes a substrate, a lower DBR disposed over
the substrate, an active layer disposed over the lower DBR, and an upper
DBR. The upper DBR includes a groove and an Ohmic contact situated within
the groove to lower the vertical resistance between the contact and the
active layer. An ion implanted layer is also formed along the side wall
of the active layer to substantially confine the current flow to the
laser cavity.