Abstract: An apparatus and method for producing laser radiation from a vertical cavity semiconductor laser are disclosed. A preferred embodiment includes a quantum-well region formed over a semiconductor substrate. A first reflective surface is formed over the quantum-well region, and a second reflective surface is formed over the substrate, opposite the first reflective surface, forming a laser cavity. The quantum-well region is optically pumped, producing laser oscillation. The absorbed pump power causes a thermal lensing effect within the semiconductor material, stabilizing the transverse spatial mode of the laser cavity. The invention has applications in optical communication and laser printing.

Abstract: A series of quantum well laser chips is mounted on a frame disposed in an external cavity opposite a tuning element. Selected chips are optically pumped by a diode laser or diode laser array. The laser light from one of the facets of a selected chip is collimated by a lens onto the tuning element. The tuning element disperses the light and a portion of the dispersed light at the single frequency is coupled back to the facet causing the chip to generate single frequency TEM.sub.00 radiation.