Abstract
In this study we developed a phototransistor from a pseudomorphic high-electron-mobility transistor (pHEMT) for ultrawide-band fiber-radio communications. The phototransistor can be used not only as a photodetector for absorbing optical signals, but also as an optoelectronic mixer for up-converting intermediate frequency (IF) signals into radio carrier signals. Experimental results show that the proposed phototransistor can provide good mixing performance for the lightwave and microwave signals. It can also simplify the internal structure of a radio access unit (RAU) for ultrawide-band (UWB) fiber-radio systems.