Limitations to Power Conversion Efficiency of InP Based Uni-traveling-carrier Photodiodes Due to Space Charge Resistance
The limiting mechanism for power conversion efficiency of uni-traveling-carrier photodiodes (UTC-PDs) for generating microwave signals is discussed. Experimental results are shown for a waveguide UTC-PD with a bandwidth of 50 GHz. The space charge resistance of this device is extracted and shown to limit the maximum power conversion efficiency to around 4%.
Light-based educational outreach activities for pre-university students
We have developed three light-based educational outreach activities for pre-university students, emphasizing experiential hands-on components for core learning. These activities leverage concepts from integrated optics and solid-state lighting, centering upon (1) building a free-space optical link, (2) subtractive and additive color mixing, and (3) guiding light using gelatin "waveguides". We garner considerable excitement in students when activities culminate in a "challenge" with an almost competitive nature. Leaders emphasize important research practices such as learning from the success of others' experiments, making and testing informed hypotheses, persistence in understanding and solving problems, and the desire to improve upon even a working solution.