Performance Characterization of Heterojunction Bipolar Transistor as an Optoelectronic Mixer

This paper explains the development of physical model Heterojunction Bipolar Transistor (HBT) and characterizes its performance as an optoelectronic mixer (OEM). HBT has been identified as a suitable device to be implemented in optoelectronic mixers by simultaneously photodetecting an intensity modulated laser beam at 1550nm and frequency translating the detected signal to a higher or lower frequency which can provide high mixing efficiency and required condition for an oscillator. The HBT OEM was designed, modeled and simulated by using APSYS Crosslight software. Data from the simulation such as the gummel plot, energy band diagram and other characteristics have been generated and analyzed. The device was analyzed considering 1550nm wavelength with up to 30GHz modulating signal frequency. Hence, the designed HBT is found to be possible for the implementation of the broadband RoF system as it can perform the photodetection, amplification and frequency conversion simultaneously as required at RoF remote antenna unit..