Proposal for diminishment of the polarization-dependency in a Si-nanowire multimode interference (MMI) coupler by tapering the MMI section

• This letter presents a design for diminishing the polarization-dependency of a Si nanowire-based multimode interference (MMI) coupler by using a tapered MMI section. The entrance width and waist width of the tapered MMI section are optimized to obtain a polarization-insensitive MMI length for N-fold self-imaging. The MMI section with a diminished polarization-dependency has a relatively large entrance width, which is beneficial to the separation of adjacent access waveguides for minimizing the coupling between them. One can tune the power splitting ratio of a 2 x 2 Si-nanowire MMI coupler by adjusting the entrance and the waist width of the tapered MMI section.

Keyword

multimode interference (MMI)

nanowire

polarization

Si

taper

wave-guides

fabrication

devices

design

Publication and Content Type

ref (subject category)

art (subject category)