Numerical Study of the Optical Saturation and Voltage Control of a Transistor Vertical-Cavity Surface-Emitting Laser

An n-p-n transistor vertical-cavity surface-emitting laser (TX-VCSEL) is described and numerically modeled by Crosslight PICS3D. For a given collector-emitter voltage V _CE, the optical output power as a function of the base current IB has three regions: 1) below-threshold, 2) linear increase, and 3) saturation. Different from the saturation caused by thermal effect and gain compression, this new-observed optical saturation comes from the three-port operation of the TX-VCSEL. The saturation power is determined by V _CE, with an approximately linear relationship. This enables new applications with voltage control of laser in future optoelectronic integrated circuits.