This Presidential Young investigator award will be used to support a research program in high speed circuits and devices for picosecond and millimeter-wave functions. Electronic circuits and devices performing time-domain (pulsed and other transient signals, logic) are an order of magnitude poorer in performance (speed) than comparable circuits and devices in narrowband millimeter wave systems. This discrepancy arises from both technological reasons (the bandwidth-efficiency limitations in matching to lumped-element devices) and historical/economic factors (strong research funding and large markets for narrowband microwave technologies used in radar). There is now strong demand for pulse and time-domain circuits operating on the 1- 100 ps time scale, in high-speed logic, multi-gagahertz fiber-optic digital transmission, real-time high-capacity signal processing, and instrumentation. We will address these areas by concurrent development of novel circuit designs and the required high-speed semiconductor devices. In the first year of the program, we will start development of devices and circuits for multi-gagahertz fiber- optic transmission. The bandwidth of semiconductor laser, photodetectors, and optical fibers has exceeded the capacity of digital decision, retiming, and multiplexing/demultiplexing circuits. The required digital functions can be performed with diode switching and pulse generation circuits similar to those previously demonstrated for picosecond pulse generation and sampling. A target goal for the NSF program will be the first demonstration of working diode multiplexing circuits at the end of the first year. The PYI funding will then be used to support initial investigation and process development for fabrication of high-speed 3-terminal devices (heterojunction bipolar transistors or modulation-doped field-effect transistors) to be used in novel high speed fiber-optic and millimeter-wave receivers and high-speed instrumentation.
