High single-mode output power from compact external microcavity surface-emitting laser diode

Transverse mode control is demonstrated in an electrically pumped surface-emitting laser diode coupled to an external microcavity with room-temperature single-mode powers reaching 2.0 mW continuous wave and 36.7 mW pulsed. The wavelength chirp is less than 0.044 nm for the pulsed results. The external microcavity is formed with a flat dielectric mirror placed less than 700 μm from the wafer surface. Diffraction and spatial filtering in the external cavity provide high-order mode suppression and produce a large fundamental mode of width 36 μm. This external cavity geometry readily lends itself to integration.