Bow-Tie Hybrid Plasmonic Waveguides

Abstract

We propose a hybrid plasmonic waveguide that incorporates a semiconductor-insulator-metal bow-tie configuration within a low-index gap guarded by semiconductor and metallic nanostructures. Ultratight field confinement (A eff ∼ λ 2 /3100 − λ 2 /120) in conjunction with reasonable propagation distance (L ∼ 56-138 μm) can be achieved simultaneously at a telecommunication wavelength. Compared to a conventional hybrid waveguide, the effective mode area and propagation loss of a typical bow-tie hybrid configuration are reduced by 2-89% and 34-62%, respectively, whereas the figure of merit is enhanced by 53-700%, along with increased power ratio inside the gap region for small gap cases. Studies on fabrication tolerance, waveguide crosstalk, and loss compensation reveal its robust property for practical implementations and remarkable feasibility to realize ultracompact passive and active components. Moreover, we also reveal the broadband feature of the waveguide and show that its concept can be applicable to various other metallic configurations as well, which may open up possibilities for the inventions of numerous high-performance plasmon waveguides and components.

A Metal-Cap Wedge Shape Hybrid Plasmonic Waveguide for Nano-Scale Light Confinement and Long Propagation Range

“…Nevertheless, the issues of large propagation loss and diffraction limit can be resolved by another wave-guiding mechanism, known as hybrid plasmonic waveguide (HPW), which essentially combines the mechanisms of dielectric and plasmonic waveguides [12][13][14][15][16]. Different types of the HPWs have been reported in literature [9,[17][18][19][20][21]. Further, the silicon-on-insulator (SOI) based HPWs and optical devices are suffering from monolithic integration with active optical devices at optical communication wavelengths.…”

A CMOS-Compatible Hybrid Plasmonic Slot Waveguide With Enhanced Field Confinement

“…S URFACE plasmon polaritons (SPPs) have attracted significant research interest in the past three decades because of their remarkable properties, such as energy asymptote in dispersion curve, resonance, field enhancement, large surface area, bulk sensitivity, and subwavelength confinement [1]- [4]. However, semiconductor based plasmonics have to face a fundamental challenge-high optical loss, especially when highpermittivity dielectric materials such as semiconductors are involved [2], [4].…”

“…S URFACE plasmon polaritons (SPPs) have attracted significant research interest in the past three decades because of their remarkable properties, such as energy asymptote in dispersion curve, resonance, field enhancement, large surface area, bulk sensitivity, and subwavelength confinement [1]- [4]. However, semiconductor based plasmonics have to face a fundamental challenge-high optical loss, especially when highpermittivity dielectric materials such as semiconductors are involved [2], [4]. To overcome this drawback, hybrid plasmonic waveguides (HPWs) have been proposed, which are capable of providing a better tradeoff between field confinement and propagation loss, as compared with their conventional plasmon waveguiding counterparts [3], [5]- [8].…”

“…To overcome this drawback, hybrid plasmonic waveguides (HPWs) have been proposed, which are capable of providing a better tradeoff between field confinement and propagation loss, as compared with their conventional plasmon waveguiding counterparts [3], [5]- [8]. The coupling between the dielectric and the plasmonic modes enables HPWs to confine light at the nanoscale domain and allow effective subwavelength transmission in non-metallic regions [4], [9], [10]. The rapidly growing family of HPWs can be divided into two main categories: (i) conventional configurations that comprise a high-index dielectric nanowire separated from a metal surface by a nanoscale dielectric gap and (ii) silicon-based waveguides composed of truncated metallic strips deposited over silicon-on-insulator (SOI) substrates [4].…”

“…The coupling between the dielectric and the plasmonic modes enables HPWs to confine light at the nanoscale domain and allow effective subwavelength transmission in non-metallic regions [4], [9], [10]. The rapidly growing family of HPWs can be divided into two main categories: (i) conventional configurations that comprise a high-index dielectric nanowire separated from a metal surface by a nanoscale dielectric gap and (ii) silicon-based waveguides composed of truncated metallic strips deposited over silicon-on-insulator (SOI) substrates [4]. In order to further improve their guiding performance, a number of modified HPWs structures have been proposed [11]- [14].…”