Design and modeling of an ultra-compact 2x2 nanomechanical plasmonic switch

A 2x2 Mach-Zehnder optical switch design with a footprint of 0.5 μm x 2.5 μm using nanomechanical gap plasmon phase modulators [Nat. Photonics 9(4),267-273(2015)] is presented. The extremely small footprint and modest optical loss are enabled by the strong phase modulation of gap plasmons in a mechanically actuated 17 nm air gap. Frequency-domain finite-element modeling at operating wavelength 780 nm shows that the insertion loss is ≤ 8.5 dB, the extinction ratio is > 25 dB, and crosstalk for all ports is > 24 dB. A design optimization approach and its dependence on geometrical parameters are discussed.