Optical Antenna-Based Photodetectors [BPN609]
As CMOS devices shrink in physical size, electrical interconnects between the devices will consume an ever-greater proportion of total chip power. A promising solution is to use silicon photonics for intra- and inter-chip communications. To be cost effective, both the optical transmitter and receiver must be made small and highly efficient. In addition, chip scale integration is important, meaning CMOS compatible materials and processes are required. The traditional tradeoff for photodiodes is between smaller size and high efficiency due to a limited absorption length of the semiconductor. We have proposed using both optical antennas for shrinking free space photodiodes and metal cavities for waveguide integration. The waveguide integrated design uses only CMOS materials and UV lithography dimensions to achieve a theoretical efficiency of over 50% for less that 90 aF capacitance at telecom wavelengths. Future work will experimentally demonstrate and characterize these nanophotodiodes.