The research topics focus on the design, fabrication, and characterization of high-speed microwave III-V semiconductor electronic and optoelectronic devices. The main interest is developing the novel device, the light emitting transistor (LET) and transistor laser (TL), which is a three-port device with simultaneous electrical and optical output. The device demonstrates a fast-recombining carrier lifetime (in picosec range) than conventional LEDs or diode lasers, resulting in a resonance-free laser response and 7 GHz spontaneous modulation bandwidth (world record). It can help reduce the cost, complexity, and heat problem of current communication system. The "transistor-like" building block is suitable for next-generation photonic integrated circuit (PIC) application.