Design and fabrication of hybrid SPP waveguides for ultrahigh-bandwidth low-penalty terabit-scale data transmission

Lightwave nano-converging enhancement by an arrayed optical antenna based on metallic nano-cone-tips for CMOS imaging detection

A kind of gold-coated glass nano-cone-tips (GGNCTs) is developed as an arrayed optical antenna for highly receiving and converging incident lightwaves. A local light field enhancement factor (LFEF) of ~ 2 × 10⁴ and maximum light absorption of ~ 98% can be achieved. The near-field lightwave measurements at the wavelength of 633 nm show that the surface net charges over a single GGNCT make a typical dipole oscillation and the energy transmits along the wave vector orientation, thus leading to a strong local light field enhancement. An effective detection method by near-field coupling an arrayed GGNCT and complementary metal-oxide-semiconductor (CMOS) sensor for highly efficient imaging detection is proposed. The lightwave detection at several wavelengths, including typical 473 nm, 532 nm, 671 nm, and 980 nm, shows a notable characteristic that a better capability of the net charge distribution adjusting and localized aggregating can be obtained at the absorption peak of the GGNCT developed and a stronger signal detection achieved. The research lays a foundation for further developing a light detector with an ideal optoelectronic sensitivity and broad spectral suitability, which is based on integrating GGNCTs as an arrayed optical antenna with common sensors.

Hybrid plasmonic slot waveguide with a metallic grating for on-chip biosensing applications

Designing reliable and compact integrated biosensors with high sensitivity is crucial for lab-on-a-chip applications. We present a bandpass optical filter, as a label-free biosensor, based on a hybrid slot waveguide on the silicon-on-insulator platform. The designed hybrid waveguide consists of a narrow silicon strip, a gap, and a metallic Bragg grating with a phase-shifted cavity. The hybrid waveguide is coupled to a conventional silicon strip waveguide with a taper. The effect of geometrical parameters on the performance of the filter is investigated by 3D finite-difference time-domain simulations. The proposed hybrid waveguide has potential for sensing applications since the optical field is pulled into the gap and outside of the silicon core, thus increasing the modal overlap with the sensing region. This biosensor offers a sensitivity of 270 nm/RIU, while it only occupies a compact footprint of 1.03µm×17.6µm.

Releasing the light field in subwavelength grating slot microring resonators for athermal and sensing applications

Silicon-on-insulator (SOI) platforms have attracted increasing interest for photonic integrated devices with an ultra-small footprint. The distinct feature is the strong light confinement in the silicon region due to a high refractive-index-contrast. In contrast, releasing the light field out of the silicon region is also of great significance for providing a useful supplement to existing light guiding mechanisms and for facilitating versatile applications. Here, subwavelength grating slot (SWGS) microring resonators, which can effectively release light out of the silicon region for athermal and sensing applications, are proposed and demonstrated. The mechanism of releasing light relies on the combination of a surface enhanced supermode in a slot waveguide and a Bloch mode in a subwavelength grating waveguide. Four types of racetrack microring resonators (strip, slot, strip-SWGS, and slot-SWGS) were fabricated for comparison. The slot-SWGS microring resonator shows the best performance for athermal and sensing applications. The demonstrations may be useful for new releasing-light-enabled devices and applications.

On-chip silicon photonic signaling and processing: a review

The arrival of the big data era has driven the rapid development of high-speed optical signaling and processing, ranging from long-haul optical communication links to short-reach data centers and high-performance computing, and even micro-/nano-scale inter-chip and intra-chip optical interconnects. On-chip photonic signaling is essential for optical data transmission, especially for chip-scale optical interconnects, while on-chip photonic processing is a critical technology for optical data manipulation or processing, especially at the network nodes to facilitate ultracompact data management with low power consumption. In this paper, we review recent research progress in on-chip photonic signaling and processing on silicon photonics platforms. Firstly, basic key devices (lasers, modulators, detectors) are introduced. Secondly, for on-chip photonic signaling, we present recent works on on-chip data transmission of advanced multi-level modulation signals using various silicon photonic integrated devices (microring, slot waveguide, hybrid plasmonic waveguide, subwavelength grating slot waveguide). Thirdly, for on-chip photonic processing, we summarize recent works on on-chip data processing of advanced multi-level modulation signals exploiting linear and nonlinear effects in different kinds of silicon photonic integrated devices (strip waveguide, directional coupler, 2D grating coupler, microring, silicon-organic hybrid slot waveguide). Various photonic processing functions are demonstrated, such as photonic switch, filtering, polarization/wavelength/mode (de)multiplexing, wavelength conversion, signal regeneration, optical logic and computing. Additionally, we also introduce extended silicon+ photonics and show recent works on on-chip graphene-silicon photonic signal processing. The advances in on-chip silicon photonic signaling and processing with favorable performance pave the way to integrate complete optical communication systems on a monolithic chip and integrate silicon photonics and silicon nanoelectronics on a chip. It is believed that silicon photonics will enable more and more emerging advanced applications even beyond silicon photonic signaling and processing.

Hybrid Plasmonic Microring Nano-Ruler

Surface plasmonic polariton (SPP) has attracted increasing interest for its ability of confining light in the subwavelength scale and breaking the diffraction limit. Recently, there have appeared several important developments of SPP applied in plasmon rulers, waveguides and resonators. By combing these concepts we present a novel hybrid plasmonic microring nano-ruler relying on the sensitive hybrid mode property and the microring resonator structure. The designed nano-ruler can measure distance in nanoscale resolution and offer adjustable sensitivity, which exceeds 14.8 as the distance is less than 5 nm by recording the transmission spectra and outstrips 200 dB/nm by observing the shift of output intensity. These demonstrations suggest that hybrid plasmonic microring nano-ruler could be a promising candidate enabling high-resoluation measurement.

CMOS plasmonics in WDM data transmission: 200 Gb/s (8 × 25Gb/s) transmission over aluminum plasmonic waveguides

We demonstrate wavelength-division-multiplexed (WDM) 200 Gb/s (8 × 25 Gb/s) data transmission over 100 μm long aluminum (Al) surface-plasmon-polariton (SPP) waveguides on a Si₃N₄ waveguide platform at telecom wavelengths. The Al SPP waveguide was evaluated in terms of signal integrity by performing bit-error-rate (BER) measurements that revealed error-free operation for all eight 25 Gb/s non-return-to-zero (NRZ) modulated data channels with power penalties not exceeding 0.2 dB at 10^-9. To the best of our knowledge, this is the first demonstration of WDM enabled data transmission over complementary-metal-oxide-semiconductor (CMOS) SPP waveguides fueling future development of CMOS compatible plasmo-photonic devices for on-chip optical interconnections.