An active gain region sandwiched between a 100% reflective bottom Bragg mirror
and an intermediate partially reflecting Bragg mirror is formed on a lower surface
of a supporting substrate, to thereby provide the first ("active") resonator cavity
of a high power coupled cavity surface emitting laser device. The bottom mirror
is preferably in direct thermal contact with an external heat sink for maximum
heat removal effectiveness. The reflectivity of the intermediate mirror is kept
low enough so that laser oscillation within the active gain region will not occur.
The substrate is entirely outside the active cavity but is contained within a second
("passive") resonator cavity defined by the intermediate mirror and a partially
reflecting output mirror, where it is subjected to only a fraction of the light
intensity that is circulating in the gain region. The active gain region is preferably
electrically excited, with a circular bottom electrode formed by an oxide current
aperture between the bottom mirror and the heat sink, and with an annular top electrode
formed on an upper surface of the substrate.
