Wedge Surface Plasmon Polariton Waveguides Based on Wet-Bulk Micromachining

Abstract

In this paper, we propose and investigate the modal characteristics of wedge surface plasmon polariton (SPP) waveguides for guiding surface plasmon waves. The wedge SPP waveguides are composed of a silver layer deposited onto the surface of a wedge-shaped silicon dielectric waveguide. The wedge-shaped silicon dielectric waveguides are explored from the anisotropic wet etching property of single crystal silicon. The wedge SPP waveguides are embedded in a dielectric medium to form the metal–dielectric interface for guiding the surface plasmon waves. The propagation characteristics of the wedge SPP waveguides at the optical telecommunication wavelength of 1.55 μm are evaluated by a numerical simulation. The influence of the physical parameters such as the dimensions of the wedge SPP waveguide and the refractive index of the dielectric medium on the propagation of the surface plasmon wave is investigated. In addition, by comparing the propagation characteristics, we derive the wedge SPP waveguide with the optimal performance.

Plasmon Wave Propagation Property of Metal Wedge Plasmonic Waveguides Covered by a Protective Oxide Layer

“…4a). This is due to the fact that for a metal wedge embedded in a dielectric medium, the propagation length and propagation mode area decrease with the increment of the refractive index of operation medium [16]. For a 2 nm thin SiO 2 layer, LSPP of the proposed waveguide can be enhanced by a factor of 7.5 compared to that of the Au wedge embedded in air for the case t m = 250 nm (543 µm compared to 72 µm), Fig.…”

“…Figure 1 (a) shows the cross-section of conventional metal wedge plasmonic waveguide. The wedge plasmonic waveguide is formed by depositing a thin metal layer on a silicon waveguide (SW) which can be fabricated by using the anisotropic wet etching property of single crystal silicon in potassium solution [16,23]. Therefore, the apex angle of SW is 70o.…”

“…SPP waveguides can be found in applications such as fundamental elements in integrated nanophotonic circuits including lightwave guiding at nanoscale, optical switches, optical modulators, and ©2022 Vietnam Academy of Science and Technology optical sensors [1][2][3][4][5][6][7][8][9][10][11][12]. Various types of SPP waveguide have been proposed for improving the propagation length while keeping the propagation mode area at subwavelength size such as metallic nanowires [13], metal strips [14], and wedge-shaped waveguides [15,16]. Among these waveguides, the wedge-shaped SPP waveguides show an excellent capability of the tight lightwave confinement around the apex of metallic wedge [3].…”

Surface acoustic wave actuated plasmonic signal amplification in a plasmonic waveguide

“…Over the last few decades, several plasmonic waveguide structures have been modeled theoretically and demonstrated experimentally. The fundamental structures of plasmonic waveguides, including metal V-shape grooves [ 15 ], wedges [ 16 ], ring resonators [ 17 ], and nanowires [ 18 ], exhibit decent confinement but with tradeoffs of high propagation loss along the metal interface. Therefore, researchers have developed a hybrid plasmonic waveguide, which combines the properties of a silicon slab waveguide and surface plasmon, to improve the propagation length of up to several hundred micrometers.…”

Design Investigation of 4 × 4 Nonblocking Hybrid Plasmonic Electrooptic Switch

“…Different structures of lasers [25], waveguides [26], photodetectors [27][28][29], optical modulators [30,31], and optical switches [32,33] have been implemented in different material systems using plasmonic technology. It is worth mentioning here that conventional plasmonic waveguides based on metal/dielectric or metal-dielectric-metal structure are characterized by relatively high intrinsic loss [34,35]. To overcome this problem, hybrid plasmonic waveguide has been proposed, where a thin dielectric layer of low refractive index such as DLD164 (=1.83 at 1550 nm operating wavelength) is sandwiched between the dielectric substrate (silicon) and the metal cladding [36][37][38].…”