Design and Fabrication of Heterojunction Bipolar Light-Emitting Transistor for Free-Space Optical Communication

React to the constantly growth of mobile and media applications, optical communications and high speed wireless networks will be the information transmission of future. Moreover, consider of heterojunction bipolar light-emitting transistor (HBLET) which could provide both optical and electrical signals at the same time and capability of transmitting a modulated light signal so that these devices will be suitable for use in optical communications or optoelectronic integrated circuits, etc. In view of all this, our project will focus on the design and fabrication of a high-efficiency HBT/HBLET. Experimentally, in order to improve the light output characteristic of HBLET after the careful design of the epitaxial structures of InGaP/GaAs HBT/HBLET and device made, we will put an optical cavity into the HBLETs during device fabrication process (i.e., forming a cleaved bar, an oxide aperture and a bottom reflector in the HBLETs). Because of optical interference effect, these HBLETs fabricated with an optical cavity will show a higher light output (P0 ＞ 10 mW), improved directionality and enhanced 3 dB modulation frequency (f3dB ＞ 500 MHz). To improve power efficiency as well as immunity to multipath interference, a directed line-of-sight optical link with a high-speed photodiode and the optical lenses is preferentially used for HBLET-based optical communication systems capable of transmitting a data rate exceeding 1 Gbit/s.

Project ID:PB10608-2403
External Project ID:MOST106-2221-E182-047