Compact wavelength add-drop multiplexers using Bragg gratings in coupled dielectric-loaded plasmonic waveguides

TL;DR

This paper introduces a compact wavelength add-drop multiplexer based on dielectric-loaded surface plasmon-polariton waveguides, combining routing and filtering in a 20-micron device for telecom wavelengths, with experimental validation.

Contribution

It presents a novel, miniaturized design of a wavelength multiplexer using Bragg gratings in coupled plasmonic waveguides, demonstrating practical fabrication and characterization methods.

Findings

Device operates at telecom wavelengths with ~70 nm separation

Achieved a 20-micron-long device with functional routing and filtering

Experimental results agree with numerical simulations

Abstract

We report a novel design of a compact wavelength add-drop multiplexer utilizing dielectric-loaded surface plasmon-polariton waveguides (DLSPPWs). The DLSPPW-based configuration exploits routing properties of directional couplers and filtering abilities of Bragg gratings. We present practical realization of a 20-$\mu$m-long device operating at telecom wavelengths that can reroute optical signals separated by approximately 70 nm in the wavelength band. We characterize the performance of the fabricated structures using scanning near-field optical microscopy as well as leakage-radiation microscopy and support our findings with numerical simulations.