PIPED: A silicon-plasmonic high-speed photodetector

Silicon-plasmonic photodetection based on internal photoemission exploits the intrinsic absorption in plasmonic waveguides at metal-dielectric interfaces. For this purpose we designed an asymmetric metal-semiconductor-metal waveguide with a width of 75 nm. Our plasmonic internal photoemission detector (PIPED) shows a rec-ord-high photocurrent sensitivity of up to S = 0.12 A / W for light at a wavelength of 1550 nm. The opto-electronic bandwidth is extremely large and allows data reception at rates of at least 40 Gbit/s. As another appli-cation, photomixing of two different optical carriers incident on the PIPED generates photocurrents with THz-frequencies, which can be used for short-range wireless communication. Finally, because in contrast to ordinary pin-photodetectors the sensitivity S(U) depends on the voltage U across the device, a PIPED can be employed for all-optical heterodyne reception and down-conversion of data on a THz carrier.