Waveguide integrated surface plasmon photodetector: Design, fabrication, and measurement

Abstract

The thesis investigates the design, fabrication, and experimental demonstration of a photodetector integrated into a thin metal stripe waveguide of finite width, operating at optical infrared wavelengths. The metallic stripe, which is clad by lightly doped silicon at the bottom and air on the top, supports the propagation of bound optical modes having very high loss (∼ 1dB/mum) and submicron field confinement in the axis perpendicular to the stripe width. The metal/silicon interface also has electrically rectifying characteristics, formally described as a Schottky diode. The theoretical model for the electrical performance of the photodiode is combined with a numerical study of the optical modes supported by the waveguide, and used to present theoretical performance predictions. A few designs are fabricated on a silicon wafer and tested experimentally, with successful demonstration of photodetection. The device has promise for applications in short-range optical interconnects, integrated optics, and silicon based photonic circuits.