Room temperature continuous wave operation of a heterojunction bipolar transistor laser

Continuous wave laser operation at 25°C, with simultaneous electrical gain, of an InGaP–GaAs heterojunction bipolar transistor laser, with AlGaAs optical confining layers and an InGaAs recombination quantum well incorporated into the p-type base region, is demonstrated. At laser threshold (IB=40mA, VCB=0, 25°C), the transistor current gain β=ΔIC∕ΔIB in common-emitter operation changes abruptly (2.3→1.2,β>1), with laser modes developing at wavelength λ∼1006nm. Direct three-port modulation of the transistor laser at 3GHz is demonstrated for a device with a 2.2μm emitter width and a 850μm length between cleaved Fabry–Perot facets (which is the performance of an exploratory device and not near the limits).