Ultra-large nonlinear parameter in graphene-silicon waveguide structures

Abstract

Mono-layer graphene integrated with optical waveguides is studied for the purpose of maximizing E-field interaction with the graphene layer, for the generation of ultra-large nonlinear parameters. It is shown that the common approach used to minimize the waveguide effective modal area does not accurately predict the configuration with the maximum nonlinear parameter. Both photonic and plasmonic waveguide configurations and graphene integration techniques realizable with today's fabrication tools are studied. Importantly, nonlinear parameters exceeding 10(4) W(-1)/m, two orders of magnitude larger than that in silicon on insulator waveguides without graphene, are obtained for the quasi-TE mode in silicon waveguides incorporating mono-layer graphene in the evanescent part of the optical field. Dielectric loaded surface plasmon polariton waveguides incorporating mono-layer graphene are observed to generate nonlinear parameters as large as 10(5) W(-1)/m, three orders of magnitude larger than that in silicon on insulator waveguides without graphene. The ultra-large nonlinear parameters make such waveguides promising platforms for nonlinear integrated optics at ultra-low powers, and for previously unobserved nonlinear optical effects to be studied in a waveguide platform.

Active Nanophotonic Circuitry Based on Dielectric‐loaded Plasmonic Waveguides

“…[ 54,52 ] Finally, it should be noted that graphene-based DLSPPW waveguides have been recently proposed, promising electrically-controlled active functionalities and enhanced nonlinear properties in mid-to far-infrared regions. [ 194,195 ] …”

Nonlinear photonic waveguides for on-chip optical pulse compression

“…Graphene's nonlinear figure of merit has previously been calculated to be ∼1.3, lower than that in wide‐bandgap CMOS materials such as silicon nitride because of its large two‐photon absorption coefficient. However, its figure of merit exceeds that of silicon (∼0.3), which makes graphene a good material for raising the nonlinear performance of silicon‐waveguide‐based structures . In addition, graphene can be easily grown using chemical vapor deposition techniques and transferred onto the waveguides to augment the nonlinear parameter of the waveguide over which the frequency chirp occurs.…”

“…In addition, graphene can be easily grown using chemical vapor deposition techniques and transferred onto the waveguides to augment the nonlinear parameter of the waveguide over which the frequency chirp occurs. Silicon–graphene waveguide structures have recently been shown to possess much larger nonlinear parameters than their nongraphene counterparts . In addition, in each of the demonstrated integrated optical pulse compressors, both the dispersion and nonlinearity of the compressor platform is fixed.…”

“…Graphene may further be adopted for electrical or optical modulation of the amount of generated nonlinear phase to achieve dynamic tuning of the output pulse width. In graphene, the optical transparency can be varied with electrical bias . This phenomenon coupled with graphene's giant Kerr nonlinearity provides a unique mechanism to tailor the extent of nonlinear phase acquisition and equivalently, the output pulse width.…”

Nonlinear graphene plasmonics

“…However, the analyses of these waveguides are not complete due to graphene's high nonlinearity, which would certainly overshadow the effects from the dielectric Kerr nonlinearities. The second class of waveguides exploits both the tight confinement of graphene plasmons and the ultrahigh Kerr nonlinearity of graphene [51,56,111,[122][123][124][125][126][127][128][129][130]. Here, squeezing of the plasmonic modes into a small effective area enables a surface-induced nonlinear enhancement (SINE) effect [122,131], as will be elaborated in the following section.…”