Surface Emission Vertical Cavity Transistor Laser

We demonstrate the first surface emission vertical cavity transistor laser (VCTL) operation with an InGaP heterojunction bipolar transistor incorporating the InGaAs quantum-wells in the base and vertical distributed Bragg reflectors. The transistor collector I-V characteristics show gain (β = ΔI_c/ΔI_B) compression, β decreasing from 0.52 to 0.47, due to the base recombination shifting from spontaneous to stimulated with increasing base current (I_B >; I_TH). The surface emission VCTL threshold current is I_TH ~ 3 mA for a cavity of 9×6 μm² lateral dimensions. The laser spectra at IB = 10 mA exhibit two peaks at 975.12 and 975.22 nm with linewidth Δλ ~ 0.7 Å.