No abstract

Leveraging the spatial modes of multimode waveguides using mode-division multiplexing on an integrated photonic chip allows unprecedented scaling of bandwidth density for on-chip communication. Switching channels between waveguides is critical for future scalable optical networks, but its implementation in multimode waveguides must address how to simultaneously control modes with vastly different optical properties. Here we present a platform for switching signals between multimode waveguides based on individually processing the spatial mode channels using single-mode elements. Using this wavelength-division multiplexing-compatible platform, we demonstrate a 1 × 2 multimode switch for a silicon chip that routes four data channels with low < −16.8 dB crosstalk. We show bit-error rates below 10 −9 and power penalties below 1.4 dB on all channels while routing 10 Gb/s data when each channel is input and routed separately. The switch exhibits an additional power penalty of less than 2.4 dB when all four channels are simultaneously routed. These results enable individual processing of multimode signals and high-bandwidth, flexible optical networks.

We demonstrate the modulation of silicon ring resonators at RF carrier frequencies higher than the resonance linewidth by coupling adjacent free-spectral-range (FSR) resonance modes. In this modulator scheme, the modulation frequency is matched to the FSR frequency. As an example, we demonstrate a 20 GHz modulation in a silicon ring with a resonance linewidth of only 11.7 GHz. We show theoretically that this modulator scheme has lower power consumption compared to a standard silicon ring modulator at high carrier frequencies. These results could enable future on-chip high-frequency analog communication and photonic signal processing on a silicon photonics platform.

The extraordinary transmission through silver film perforated with rectangular hole array with different aspect ratio was investigated. It was found that when the aspect ratio exceeded 7, the propagating surface plasmon polaritons (SPPs) transformed to localized resonance mode. The role of the Wood's anomaly on the shape of the transmission spectrum is investigated. By designing the rectangular hole arrays in a rectangular lattice, the Wood's anomaly can be shifted far apart from the transmission peak, the real localized resonance peak wavelength was identified and fitted well with the theoretical calculation using a simplified transmission-line model.

The experimental results of linear polarized light transmitting through an array of Archimedean spiral slots perforated on a thin metal film in the far-infrared region are demonstrated. The wavelength selective transmission spectra are examined, and the polarization selective shape resonance will lead to the polarization rotation. The sign of rotation not only depend on the handedness of the spiral but also related to specific initial polarization position. This phenomenon is different from the conventional optical activity in three-dimensional chiral molecules but rather similar to the polarization selective features in rectangular or elliptical slots.