Scaling limit of silicon nano-wire waveguides

The scaling limit and optical clock frequency limit of silicon nano-wire waveguides are investigated, and a comparison between optical waveguides and electric wiring is made. The evaluation method involves investigating a confinement factor and dispersion. The confinement factor is a major factor in the scaling limit. In the terahertz region of clock frequency, dispersion becomes another major factor of the scaling limit. As a result, in 1THz, 1cm of on-chip waveguide length, the minimum waveguide width is 270nm with a wavelength of 1.55 μm. This width is four times as large as the 70nm of global wire width in 32nm node. However, clock frequency is improved by three orders.