Silicon-based Plasmonic Waveguide Research Articles

Degenerate four-wave mixing in silicon hybrid plasmonic waveguides.

Silicon-based plasmonic waveguides show high confinement well beyond the diffraction limit. Various devices have been demonstrated to outperform their dielectric counterparts at micrometer scales, such as linear modulators, capable of generating high field confinement and improving device efficiency by increasing access to nonlinear processes, limited by ohmic losses. By using hybridized plasmonic waveguide architectures and nonlinear materials, silicon-based plasmonic waveguides can generate strong nonlinear effects over just a few wavelengths. We have theoretically investigated the nonlinear optical performance of two hybrid plasmonic waveguides (HPWG) with three different nonlinear materials. Based on this analysis, the hybrid gap plasmon waveguide (HGPW), combined with the DDMEBT nonlinear polymer, shows a four-wave mixing (FWM) conversion efficiency of -16.4 dB over a 1μm propagation length, demonstrating that plasmonic waveguides can be competitive with standard silicon photonics structures over distances three orders of magnitude shorter.

Demonstration of low-loss on-chip integrated plasmonic waveguide based on simple fabrication steps on silicon-on-insulator platform

We report the experimental realization of a robust silicon-based plasmonic waveguide structure which can theoretically provide sub-wavelength confinement for Ex- and Ey-polarized surface plasmon polariton modes. Our waveguides exhibit propagation loss as low as 0.2 dB/μm with ∼50% coupling efficiency.

Nonlinear propagation in silicon-based plasmonic waveguides from the standpoint of applications

Silicon-based plasmonic waveguides can be used to simultaneously transmit electrical signals and guide optical energy with deep subwavelength localization, thus providing us with a well needed connecting link between contemporary nanoelectronics and silicon photonics. In this paper, we examine the possibility of employing the large third-order nonlinearity of silicon to create active and passive photonic devices with silicon-based plasmonic waveguides. We unambiguously demonstrate that the relatively weak dependance of the Kerr effect, two-photon absorption (TPA), and stimulated Raman scattering on optical intensity, prevents them from being useful in μm-long plasmonic waveguides. On the other hand, the TPA-initiated free-carrier effects of absorption and dispersion are much more vigorous, and have strong potential for a variety of practical applications. Our work aims to guide research efforts towards the most promising nonlinear optical phenomena in the thriving new field of silicon-based plasmonics.

Silicon-based plasmonic waveguides

We propose and comprehensively investigate Si-based plasmonic waveguides as a means to confine and manipulate photonic signals. The high refractive index of Si assures strong confinement and a very high level of photonic integration with achievable waveguide separations of the order of 10 nm and waveguide bends with 500 nm radius at telecommunication wavelengths, while using Al and Cu plasmonic material platforms, makes such waveguides fully compatible with existing CMOS fabrication processes. Their potential future in hybrid electronic/photonic chips is further reinforced as various configurations have been shown to compensate SPP propagation loss. The group velocity dispersion of such waveguides allows over 10 Tb/s signal transfer rates. The figures of merit allowing comparison of passive and active functionalities achievable with various waveguides have also been introduced.

Monolithic integration of plasmonic waveguides into a complimentary metal-oxide-semiconductor- and photonic-compatible platform

A silicon-based plasmonic waveguide was designed and fabricated for use at telecommunications wavelengths. This waveguide is interfaced to the silicon photonics platform by use of a tapered silicon-on-insulator waveguide. Simulations indicate that this scheme excites the transverse magnetic plasmonic mode and that the electric fields are confined to the silicon-gold interface. Transmitted power is measured for several device lengths and the propagation distance and coupling efficiency are found to be 2.00 μm and 38.0%, respectively. These results demonstrate the potential for integration between silicon photonics and silicon plasmonic devices and demonstrate the ability to incorporate silicon-based plasmonic devices into complimentary metal-oxide-semiconductor electronic and photonic circuitry.