A top emitting vertical cavity surface emitting laser with an etch stop layer positioned in the top mirror stack so the stack can be etched to form a trench surrounding a mesa with the emitting area on the mesa and the trench confining current flow and lasing to the mesa....http://www.google.es/patents/US5293392?utm_source=gb-gplus-sharePatente US5293392 - Top emitting VCSEL with etch stop layer
