Compact and low-power all-optical surface plasmon switches with isolated pump and data waveguides and a rectangular cavity containing nano-silver strips

摘要

In this paper, a plasmonic all-optical switch based on a novel topology is presented. The structure is composed of a rectangular cavity coupled with two cross waveguides. Several silver strips with a tapered pattern are inserted in the rectangular cavity to create a sharp edge in the transmission spectrum of the data signal. The cavity and waveguides are filled with a non-linear insulator with high Kerr-type nonlinearity. The vertical and horizontal waveguides are used for passing the data and pump signals, respectively. When in addition to the data signal, the pump signal is also applied, the refractive index of the Kerr material changes, which triggers the switching mechanism. Allocating two different paths for the data and pump signals results in a desirable isolation between these signals. The proposed switch is numerically simulated using finite difference time domain (FDTD) method. In order to verify the FDTD simulation results, the basic switch structure is also analyzed using the transmission line method. Compact size (considering two different input ports), low pumping intensity, simplicity, symmetrical structure, suitable isolation and high contrast ratios are the marked characteristics of the proposed all-optical switch. As a result, such a structure has the potential to be used in complex integrated optical circuits.