A comprehensive theoretical analysis of end-fire coupling between dielectric-loaded surface plasmon polariton and rib/wire silicon-on-insulator (SOI) waveguides is presented. Simulations are based on the 3-D vector finite element method. The geometrical parameters of the interface are varied in order to identify the ones leading to optimum performance, i.e., maximum coupling efficiency. Fabrication tolerances about the optimum parameter values are also assessed. In addition, the effect of a longitudinal metallic stripe gap on coupling efficiency is quantified, since such gaps have been observed in fabricated structures. Finally, theoretical results are compared against insertion loss measurements, carried out for two distinct sets of samples comprising rib and wire SOI waveguides, respectively.

We demonstrate Wavelength Division Multiplexed (WDM)-enabled transmission of 480Gb/s aggregate data traffic (12x40Gb/s) as well as high-quality 1x2 thermo-optic tuning in Dielectric-Loaded Surface Plasmon Polariton Waveguides (DLSPPWs). The WDM transmission characteristics have been verified through BER measurements by exploiting the heterointegration of a 60 μm-long straight DLSPPW on a Silicon-on-Insulator waveguide platform, showing error-free performance for six out of the twelve channels. High-quality thermo-optic tuning has been achieved by utilizing Cycloaliphatic-Acrylate-Polymer as an efficient thermo-optic polymer loading employed in a dual-resonator DLSPPW switching structure, yielding a 9 nm wavelength shift and extinction ratio values higher than 10 dB at both output ports when heated to 90°C.

We demonstrate Wavelength Division Multiplexed (WDM)-enabled transmission of 480Gb/s aggregate data traffic (12x40Gb/s) as well as high-quality 1x2 thermo-optic tuning in Dielectric-Loaded Surface Plasmon Polariton Waveguides (DLSPPWs). The WDM transmission characteristics have been verified through BER measurements by exploiting the heterointegration of a 60 μm-long straight DLSPPW on a Silicon-on-Insulator waveguide platform, showing error-free performance for six out of the twelve channels. High-quality thermo-optic tuning has been achieved by utilizing Cycloaliphatic-Acrylate-Polymer as an efficient thermo-optic polymer loading employed in a dual-resonator DLSPPW switching structure, yielding a 9 nm wavelength shift and extinction ratio values higher than 10 dB at both output ports when heated to 90°C.

With metal stripes being intrinsic components of plasmonic waveguides, plasmonics provides a “naturally” energy-efficient platform for merging broadband optical links with intelligent electronic processing, instigating a great promise for low-power and small-footprint active functional circuitry. The first active Dielectric-Loaded Surface Plasmon Polariton (DLSPP) thermo-optic (TO) switches with successful performance in single-channel 10 Gb/s data traffic environments have led the inroad towards bringing low-power active plasmonics in practical traffic applications. In this article, we introduce active plasmonics into Wavelength Division Multiplexed (WDM) switching applications, using the smallest TO DLSPP-based Mach-Zehnder interferometric switch reported so far and showing its successful performance in 4×10 Gb/s low-power and fast switching operation. The demonstration of the WDM-enabling characteristics of active plasmonic circuits with an ultra-low power × response time product represents a crucial milestone in the development of active plasmonics towards real telecom and datacom applications, where low-energy and fast TO operation with small-size circuitry is targeted.

In today's Peta-flop High-Performance Computing (HPC) machines the size and power consumption appear to be daunting issues, signifying that new technological and architectural considerations will be required in order to be able to move towards Exascale-computing powers. Whereas silicon photonics emerges as a powerful technology for low-loss and high bandwidth optical connectivity in integrated circuit environments, servers and network switches are already consolidating into high-density blade enclosures in order to reduce space and cooling requirements. These determine new tasks for switching infrastructures of miniature data networks: the next generation of routing circuitry has to provide high throughput capabilities while keeping in line with the requirements of small foot-print, low power consumption and low latency. Next generation computing architectures are needed with ultra low power consumption; ultra high performance with novel photonic interconnection technologies. The objective of the recently proposed high bandwidth Photonics Interconnection Layer for Converged Microsystems using System-in-Package Technology, namely PICSiP, is to develop a CMOS compatible underlying technology to enable next generation optical computing architectures.In this work, we present a silicon photonics based integrated system-in-package platform (PICSiP) for Tb/s router application. As routing platform employ three different technologies: silicon photonics, plasmonics and electronics. Compatibility between various components has to be ensured to allow for their seamless interfacing and interoperability. The 4x4 router architecture exploits a SOI platform employing 340x400nm2 waveguide structures and hosting four 7:1 SOI multiplexing circuits, four photodiodes, an electronic IC control circuit and the 4x4 dielectric-loaded surface plasmon-polariton (DLSPP)-based switching matrix.

This tutorial reviews the physics of surface plasmon circuitry in order to bring to the fore recently demonstrated applications of surface plasmon in optoelectronics such as on-board optical interconnects or routing in datacom networks.

In this work, we present a novel wavelength multiplexing concept for an integrated label-free biosensor array employing silicon photonic Mach-Zehnder interferometers as sensors. Microring resonators act as wavelength selective elements in order to address the individual interferometers. Wire Bragg gratings terminate the interferometer arms and reflect the light back, which eliminates the risk of a wavelength mismatch between drop and add port. The characteristics of the device are discussed and the design based on FEM and 3D-FDTD simulations as well as measurements of the nanophotonic key components—micro ring resonators, Mach-Zehnder interferometers and photonic wire Bragg gratings—are presented. Measurements of combinations of the wire Bragg gratings with ring resonators and Mach-Zehnder interferometer sensors demonstrate the applicability of the reflectors in photonic circuits.

We present a novel wavelength multiplexing concept for an integrated label-free biosensor array employing silicon photonic Mach-Zehnder interferometers as sensors. Microring resonators act as wavelength selective elements in the near infrared wavelength region. The radii of the microring resonators differ to obtain resonance wavelengths that are allocated equally within the free spectral range. By choosing a wavelength where a certain microring is in resonance, an individual interferometer is addressed. Wire Bragg gratings terminate the interferometer arms and reflect the light back. The ring resonator, which dropped the light, now couples the light back into the input waveguide, where it propagates in opposite direction. A standard fiber optic circulator between the tunable laser source and the in/output separates the incoming from the outgoing light. In this work, the characteristics of the entire device are discussed. The design based on FEM and 3D-FDTD simulations as well as measurements of the nanophotonic key components namely micro ring resonators, Mach-Zehnder interferometers, and photonic wire Bragg gratings are presented. Measurements of combinations of the key components demonstrate the applicability of the reflectors in photonic circuits. Finally, for proof-of-concept, we successfully performed experiments with fluids of different refractive index differences rinsed over the sensor array.

The field of data communications and short-range interconnects in computing and High Performance Data Centers (HPCs) and Computing Systems has been up to date almost exclusively dominated by electronics, which have formed the main technological solution for the interconnection of many core/board/rack modules. In FP7-PLATON project we are investigating novel hybrid Silicon-Plasmonics components/subsystems for the demonstration of a Tb/s scale router with ultralow power consumption, footprint and end-to-end propagation delay. The breakthrough approach of PLATON relies on a novel hybrid Silicon-Plasmonics technology where Silicon Photonics is the low loss platform for the formation of the passive circuitry and Plasmonics is exploited for the active parts of the router towards reducing size and energy consumption. In this article, we will present our latest results on true WDM traffic transmission and switching using active plasmonics integrated on the Silicon-on-Insulator waveguide platform and we will outline the roadmap for future energy efficient Data Centers and HPCs with the integration of our novel technology.

Grating couplers are the best solution for testing nano-photonic circuits. Their main benefit is that they allow access via an optical fiber from the top and therefore there is no need to dice the chip and prepare the facets crucially. In the PLATON project grating couplers were designed to couple TM mode into and out of the SOI waveguides. Simulations came up with a grating coupler layout capable of theoretical coupling losses lower than 3dB for 1550 nm in TM configuration. A fully etched grating structure was chosen for fabrication simplicity and the optimal filling factor was found. The structures were fabricated using proximity error correction (PEC) and show a uniform coupling efficiency for all couplers. Therefore they are well-suited for all applications which demand for stable fiber-to-chip coupling. The spectral response of the structures was measured from 1500 to 1580 nm with 2 nm step and measuring the fiber-tofiber losses of three straight waveguides equipped with three grating couplers with different gap widths. The optimal grating period exhibits adequate coupling losses of 3.23 dB per coupler at 1557 nm, being therefore the most promising design.

The first system-level experimental results of hybrid Si-DLSPP structures incorporated into a SOI chip are reported. We demonstrate over 7nm thermo-optical tuning of a Si-Plasmonic racetrack-resonator and verify error-free 10Gb/s transmission through 60um Si-Plasmonic waveguide.

We optimized silicon photonic wire Bragg gratings covered with SU-8 for quasi-TM polarized light at a center wavelength of 1550 nm with respect to high reflectivity and large wavelength range by means of 3D FDTD simulations. The simulations resulted in a grating design providing a reflectivity of >70% over a wavelength range of 50 nm. Corresponding samples were fabricated employing e-beam lithography and reactive ion etching. The measured reflection spectrum demonstrates the good performance of the optimized Bragg grating reflector. First experimental results of a silicon photonic device combining the Bragg reflector with ring resonators for on-chip wavelength (de)multiplexing in refractometric sensor arrays are presented.

Surface plasmons polaritons are electromagnetic waves propagating along the surface of a conductor. Surface plasmons photonics is a promising candidate to satisfy the constraints of miniaturization of optical interconnects. This contribution reveiws an experimental parametric study of dielectric loaded surface plasmon waveguides ring resonators and add-drop filters within the perspective of the recently suggested hybrid technology merging plasmonic and silicon photonics on a single board (European FP7 project PLATON "Merging Plasmonic and Silicon Photonics Technology towards Tb/s routing in optical interconnects"). Conclusions relevant for dielectric loaded surface plasmon switches to be integrated in silicon photonic circuitry will be drawn. They rely on the opportunity offered by plasmonic circuitry to carry optical signals and electric currents through the same thin metal circuitry. The heating of the dielectric loading by the electric current enables to design low foot-print thermo-optical switches driving the optical signal flow.

We demonstrate experimental evidence of the data capture and the low-energy thermo-optic tuning credentials of dielectric-loaded plasmonic structures integrated on a silicon chip. We show 7-nm thermo-optical tuning of a plasmonic racetrack-resonator with less than 3.3 mW required electrical power and verify error-free 10-Gb/s transmission through a 60-μm-long dielectric-loaded plasmonic waveguide.

In this work, we optimize Bragg gratings covered with SU-8 for TM polarized light at a center wavelength of 1550 nm with respect to high reflectivity and large wavelength range employing 3D FDTD simulations. Three different types of lateral grating modulation were studied: I) complete interruption of the waveguide, II) corrugation within the waveguide width, and III) corrugation exceeding the waveguide width. The wavelength response was analyzed with a discrete Fourier transformation algorithm for a Gaussian pulse source. The investigations resulted in a grating structure providing a reflectivity of > 70% over a wavelength range of 50 nm. The transmission and the radiation losses amount both to approximately 10-15% each. Corresponding samples of these three Bragg grating structures with lengths of similar to 10 mu m were fabricated employing e-beam lithography and reactive ion etching. In order to enable the experimental verification of the reflectivity a Y-branch separates the light paths of incoming and reflected light directly on the chip. The measured reflection and transmission spectra match well with the simulations and demonstrate the good performance of the optimized Bragg grating reflector.

We present a novel wavelength multiplexing concept for an integrated sensor array based on SOI photonic MachZehnder interferometers. The characteristics of the entire device are discussed and the design, performed on the basis of FEM and 3D FDTD simulations, as well as first measurements of the nanophotonic key components–micro ring resonators and a photonic wire Bragg gratings–are presented.

We present recent work that is carried out within the FP7 project PLATON on novel Tb/s switch fabric architectures and technologies for optical interconnect applications, employing heterointegration of plasmonics, silicon photonics and electronics.

We report on a method for the fabrication of graphene on a silicon dioxide substrate by solid-state dissolution of an overlying stack of a silicon carbide and a nickel thin film. The carbon dissolves in the nickel by rapid thermal annealing. Upon cooling, the carbon segregates to the nickel surface forming a graphene layer over the entire nickel surface. By wet etching of the nickel layer, the graphene layer was allowed to settle on the original substrate. Scanning tunneling microscopy (STM) as well as Raman spectroscopy has been performed for characterization of the layers. Further insight into the morphology of the layers has been gained by Raman mapping indicating micrometer-size graphene grains. Devices for electrical measurement have been manufactured exhibiting a modulation of the transfer current by backgate electric fields. The presented approach allows for mass fabrication of polycrystalline graphene without transfer steps while using only CMOS compatible process steps.

The absence of a band gap in graphene restricts its straightforward application as a channel material in field-effect transistors. In this letter, we report on a new approach to engineer a band gap in graphene field-effect devices (FEDs) by controlled structural modification of the graphene channel itself. The conductance in the FEDs is switched between a conductive ldquoon-staterdquo and an insulating ldquooff-staterdquo with more than six orders of magnitude difference in conductance. Above a critical value of an electric field applied to the FED gate under certain environmental conditions, a chemical modification takes place to form insulating graphene derivatives. The effect can be reversed by electrical fields of opposite polarity or short current pulses to recover the initial state. These reversible switches could potentially be applied to nonvolatile memories and novel neuromorphic processing concepts.