Deep-subwavelength light transmission in hybrid nanowire-loaded silicon nano-rib waveguides

Abstract

Hybrid plasmonic waveguides leveraging the coupling between dielectric modes and plasmon polaritons have emerged as a major focus of research attention during the past decade. A feasible way for constructing practical hybrid plasmonic structures is to integrate metallic configurations with silicon-on-insulator waveguiding platforms. Here we report a transformative high-performance silicon-based hybrid plasmonic waveguide that consists of a silicon nano-rib loaded with a metallic nanowire. A deep-subwavelength mode area (λ 2 ∕4.5 × 10 5 − λ 2 ∕7 × 10 3), in conjunction with a reasonable propagation distance (2.2-60.2 μm), is achievable at a telecommunication wavelength of 1.55 μm. Such a nano-rib-based waveguide outperforms its conventional hybrid and plasmonic waveguiding counterparts, demonstrating tighter optical confinement for similar propagation distances and a significantly enhanced figure of merit. The guiding properties of the fundamental mode are also quite robust against possible fabrication imperfections. Due to the strong confinement capability, our proposed hybrid configuration features ultralow waveguide cross talk and enables submicron bends with moderate attenuation as well. The outstanding optical performance renders such waveguides as promising building blocks for ultracompact passive and active silicon-based integrated photonic components.

Optical Transport Properties of Graphene Surface Plasmon Polaritons in Mid-Infrared Band

“…As shown in Figure 4, L g and Im(β) are both negative at the substrate thicknesses of 15 and 20 nm when the wavelength is less than a certain value, which is because graphene SPPs cannot be excited under these conditions. Figure 3 shows the transmission characteristics on incident wavelengths for different applied voltages (1,2,3,4, and 5 V), and the incident wave is in the mid-infrared region (2500-25,000 nm). Here, Si is selected as the graphene substrate and dielectric material, and the substrate thickness is 10 nm.…”

“…The development of the optoelectronics industry brought about by new emerging technologies including silicon photonics, photonic crystals, and surface plasmon polaritons (SPPs) has enabled optoelectronic devices to become more miniaturized, integrated, and multi-functional [1]. The miniaturization of optoelectronic devices is key to promoting the development of optoelectronic devices for very large-scale integration.…”

Hybrid Nanowire–Rectangular Plasmonic Waveguide for Subwavelength Confinement at 1550 Nm

“…They are widely used for optical manipulation at the subwavelength scale because they can restrict light to a considerably smaller range than the diffraction limit [ 17 , 18 ]. Currently, the most widely used precious metal SPPs are gold (Au) and silver (Ag) [ 19 ]. In recent years, several types of waveguides have been designed based on SPPs [ 20 , 21 , 22 ], and the normalized effective mode area of waveguides has been significantly improved [ 10 , 24 , 25 ].…”

Ultra-Low-Loss Mid-Infrared Plasmonic Waveguides Based on Multilayer Graphene Metamaterials

“…To date, the most promising approach to achieve this goal is to excite surface plasmon polaritons (SPPs) [1] by coupling photons and free electrons at metal-dielectric interfaces. For visible and near-infrared (IR) wavelengths, noble metals have been used to build various nanoscale photonic circuits [2][3][4][5]. However, alternative metallic materials are necessary because of the weak confinement of SPP modes in conventional noble metals for mid-IR and terahertz (THz) bands [6,7].…”