Design, Fabrication, and Characterization of Reflective Diffractive OpticalElements in Si for Free-Space Optical Interconnects

摘要

Diffractive optical element designs are presented for a free-space focusedoptical interconnect whereby a 4x4 array of LEDs is focused onto a 4x4 array of photodetectors. Process development for highly efficient diffractive elements is presented. Fabrication tolerances for binary level alignment and etch depth are determined. Eight-level diffractive elements are fabricated using electron beam lithography and reactive ion etching. Continuously graded gratings are fabricated using focused ion beam milling. Device fabrication is characterized by scanning electron microscopy and atomic force microscopy, and device performance is determined by measuring diffraction efficiencies. Diffractive elements, Electron beam lithography, Reactive ion etching.