Resonant optical in-well pumping of an (AlGaln)(AsSb)-based vertical-external-cavity surface-emitting laser emitting at 2.35 µm

The semiconductor heterostructure design and lasing characteristics of an optically in-well pumped (AlGaIn)(AsSb)-based vertical-external-cavity surface-emitting laser (VECSEL) emitting at 2.35 µm are presented. The pump absorption in the active quantum wells at 1.96 µm has been enhanced by a higher-order microcavity resonance. VECSEL operation in-well pumped by a thulium-doped fiber laser has been demonstrated. Compared to a VECSEL barrier pumped at 1 µm, the in-well pumped device reaches a significantly higher power efficiency, and thus a higher output power at a given pump power, due to the smaller quantum deficit and hence reduced internal heat generation. Using an intracavity SiC heat spreader, a cw output power in excess of 3 W has been achieved at a heat sink temperature of ?15 °C, and still more than 2 W at +15 °C.