Sub-fF-Capacitance Photonic-Crystal Photodetector Towards fJ/bit On-Chip Receiver

Kengo NOZAKI  Shinji MATSUO  Koji TAKEDA  Takuro FUJII  Masaaki ONO  Abdul SHAKOOR  Eiichi KURAMOCHI  Masaya NOTOMI  

IEICE TRANSACTIONS on Electronics   Vol.E100-C   No.10   pp.750-758
Publication Date: 2017/10/01
Online ISSN: 1745-1353
Type of Manuscript: INVITED PAPER (Joint Special Section on Opto-electronics and Communications for Future Optical Network)
photonic crystal waveguide,  photodetector,  buried heterostructure,  optical interconnection,  

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An ultra-compact InGaAs photodetector (PD) is demonstrated based on a photonic crystal (PhC) waveguide to meet the demand for a photoreceiver for future dense photonic integration. Although the PhC-PD has a length of only 1.7µm and a capacitance of less than 1fF, a high responsivity of 1A/W was observed both theoretically and experimentally. This low capacitance PD allows us to expect a resistor-loaded receiver to be realized that requires no electrical amplifiers. We fabricated a resistor-loaded PhC-PD for light-to-voltage conversion, and demonstrated a kV/W efficiency with a GHz bandwidth without using amplifiers. This will lead to a photoreceiver with an ultralow energy consumption of less than 1fJ/bit, which is a step along the road to achieving a dense photonic network and processor on a chip.