Broadband light coupling to dielectric slot waveguides with tapered plasmonic nanoantennas

TL;DR

This paper introduces a broadband coupling method using tapered plasmonic nanoantennas to efficiently connect free space light to dielectric slot waveguides, offering a compact alternative to traditional couplers.

Contribution

It presents a novel broadband coupling mechanism with high efficiency and small footprint, enabling new on-chip multiplexing applications.

Findings

Coupling efficiency up to 20% across a broad spectral range

Nanoantennas enable compact on-chip multiplexers/demultiplexers

Significant reduction in device footprint compared to traditional methods

Abstract

We propose and theoretically verify an efficient mechanism of broadband coupling between incident light and on-chip dielectric slot waveguide by employing a tapered plasmonic nanoantenna. Nanoantenna receives free space radiation and couples it to a dielectric slot waveguide with the efficiency of up to 20% in a broad spectral range, having a small footprint as compared with the currently used narrowband dielectric grating couplers. We argue that the frequency selective properties of such nanoantennas also allow for using them as ultrasmall on-chip multiplexer/demultiplexer devices.