Ultra-broadband and compact graphene-on-silicon integrated waveguide mode filters

Peng Xing,Dawn T H Tan,Kelvin J A Ooi

doi:10.1038/s41598-018-28076-8

Peng Xing, Dawn T H Tan + Show 1 more

Open Access

https://doi.org/10.1038/s41598-018-28076-8

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Abstract

Increasing bandwidth demands in optical communications necessitates the introduction of mode-division multiplexing (MDM) on top of the existing wavelength-division multiplexing (WDM) systems. Simultaneous management of both multiplexing systems will be a complex task, and there is the possibility of signal degradation through modal crosstalk. Here, we propose graphene-on-silicon (GOS) integrated waveguide mode filters to suppress the propagation of spurious waveguide modes at the telecommunications wavelength. Graphene’s high fabrication tolerance potentially enables surgical tailoring and deployment at targeted segments on the waveguide to absorb the undesired TE0 or TE1 modes. The proposed GOS waveguide mode filters can potentially improve the performance and reduce the device footprint of MDM systems.

Highlights

The scaling of bandwidth in optical communication systems is largely enabled by the invention of wavelength-division multiplexing (WDM) technologies four decades ago[1], and is instrumental to the large-scale adoption of optical fiber communications technology today
This shows that the graphene layer should adhere as closely as possible to the waveguide surface, while design of the Wg should take into consideration the tradeoff between device footprint and insertion losses
We have designed GOS waveguide mode filters to suppress the propagation of spurious waveguide modes, which function as auxiliary components to enhance the performance of existing modedivision multiplexing (MDM) systems

Summary

Introduction

The scaling of bandwidth in optical communication systems is largely enabled by the invention of wavelength-division multiplexing (WDM) technologies four decades ago[1], and is instrumental to the large-scale adoption of optical fiber communications technology today. MDM systems based on ADCs have limited spectrum bandwidth and are usually stringent in their fabrication tolerances. Conventional photonic waveguide mode filters often rely on the effective index differences between the desired and unwanted modes, and filter the latter using optically resonant devices like Bragg gratings and photonic crystal waveguides[4,12,13,14,15]. These devices have downsides of very narrow spectral bandwidth, low fabrication tolerances, and the build-up of the reflected optical modes may be complex to manage. Correspondence and requests for materials should be addressed to D.T.H.T.

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