Chip-integrated plasmonic Schottky photodetection based on hybrid silicon waveguides

We numerically and theoretically investigate the plasmonic Schottky photodetection in a novel hybrid silicon-on-insulator waveguide system, which consists of the silicon waveguides and detection area with the metal stripes and doped silicon film on the silicon dioxide substrate. The results illustrate that the fundamental TE mode in the silicon waveguide can be effectively coupled into the metal/silicon waveguide with the excitation of surface plasmon polaritons (SPPs). The coupling is suppressed for the TM mode due to the mismatch between the electric field distributions of the TM and SPP modes. It is found that the coupling efficiency from the TE to SPP mode is dependent on the width and height of the silicon waveguide and can significantly approach ~36.1%. The ultracompact configuration yields a high responsivity of ~21.7 mA/W and low dark current of ~0.45 μA for the photodetection at the communication wavelength. The plasmonic Schottky photodetector could find favorable applications in the chip-integrated optical interconnects and signal processing.