Low-Loss Light Guiding at the Subwavelength Scale in a Nanowire-Loaded Hybrid Bloch-Surface-Polariton Waveguide

Weijing Kong,Yu Sun,Rui Meng,Xiaochang Ni

doi:10.1109/access.2020.3032698

Abstract

We report the realization of strongly confined low-loss optical waveguiding at telecommunication wavelength by exploiting the hybridization of photonic modes guided by coupled dielectric mode and Bloch surface polaritons on the interface between one-dimensional photonic crystal and dielectric nanowire. Owing to the combined effects induced by the coupling between two types of guided modes, tight field localization in conjunction with significantly lower propagation loss can be achieved simultaneously. The characteristics of the hybrid modes are comprehensively numerically investigated through tuning key structural parameters of the coupled dielectric nanowire and its distance to the photonic crystal surface. The hybrid mode could effectively balance the compromise between the mode confinement and propagation loss for a wide geometrical parameter range. It reveals the hybrid mode is capable of enabling larger propagation distance (centimeter level) with subwavelength mode confinement, leading to a high figure of merit nearly one order of magnitude larger as compared to the conventional hybrid waves in dielectric-metal-based surface plasmon waveguides over the range of dimensions considered. The outstanding properties of the proposed guiding scheme could open up possibilities for a variety of high-performance intriguing nanophotonic components.

Highlights

Featuring simultaneously extraordinary optoelectronic properties and strong compatibility with chemical synthetic methods, dielectric-nanowire waveguides that enable ultralow-loss lightwave transportation have been regarded as one of the most fundamental building blocks for photonic integrated components and circuits [1]-[5]
By integrating metal films and periodic multilayer structures, several typical studies have been proposed and demonstrated based on the hybridization between Bloch surface polariton (BSP) mode and Surface plasmon polaritons (SPPs) mode, which show the prospect in enabling effectively balance between the mode confinement and propagation loss [43]-[45]. Compared with their SPP counterparts, limited attention has been paid to the research of improving the guiding performance of BSP in photonic components and devices up to date
FIGURE OF MERIT OF THE PROPOSED HYBRID WAVEGUIDE To further benchmark the guiding properties of the hybrid BSP mode sustained by the proposed hybrid BSP waveguide (HBSPW) structure

Summary

INTRODUCTION

Featuring simultaneously extraordinary optoelectronic properties and strong compatibility with chemical synthetic methods, dielectric-nanowire waveguides that enable ultralow-loss lightwave transportation have been regarded as one of the most fundamental building blocks for photonic integrated components and circuits [1]-[5]. By integrating metal films and periodic multilayer structures, several typical studies have been proposed and demonstrated based on the hybridization between BSP mode and SPP mode, which show the prospect in enabling effectively balance between the mode confinement and propagation loss [43]-[45] Compared with their SPP counterparts, limited attention has been paid to the research of improving the guiding performance of BSP in photonic components and devices up to date. With the geometric parameters of the proposed HBSPW are fixed at tr =125 nm, r = 150 nm, and g = 20 nm, owing to the hybridization of the dielectric mode and the BSP mode, the electric field is tightly squeezed and enhanced in the truncated layer and the gap region, showing a dramatic field confinement over the traditional BSP mode sustained by the 1D PC multilayer structure as shown above.

FIGURE OF MERIT OF THE PROPOSED HYBRID WAVEGUIDE

CONCLUSION