Showing papers on "Optical switch published in 2016"
TL;DR: In this article, the authors demonstrate an integrated platform for scalable quantum nanophotonics based on silicon-vacancy (SiV) color centers coupled to diamond nanodevices.
Abstract: Efficient interfaces between photons and quantum emitters form the basis for quantum networks and enable optical nonlinearities at the single-photon level. We demonstrate an integrated platform for scalable quantum nanophotonics based on silicon-vacancy (SiV) color centers coupled to diamond nanodevices. By placing SiV centers inside diamond photonic crystal cavities, we realize a quantum-optical switch controlled by a single color center. We control the switch using SiV metastable states and observe optical switching at the single-photon level. Raman transitions are used to realize a single-photon source with a tunable frequency and bandwidth in a diamond waveguide. By measuring intensity correlations of indistinguishable Raman photons emitted into a single waveguide, we observe a quantum interference effect resulting from the superradiant emission of two entangled SiV centers.
583 citations
TL;DR: In this article, the authors demonstrate an integrated platform for scalable quantum nanophotonics based on silicon-vacancy (SiV) color centers coupled to nanoscale diamond devices.
Abstract: Efficient interfaces between photons and quantum emitters form the basis for quantum networks and enable nonlinear optical devices operating at the single-photon level. We demonstrate an integrated platform for scalable quantum nanophotonics based on silicon-vacancy (SiV) color centers coupled to nanoscale diamond devices. By placing SiV centers inside diamond photonic crystal cavities, we realize a quantum-optical switch controlled by a single color center. We control the switch using SiV metastable orbital states and verify optical switching at the single-photon level by using photon correlation measurements. We use Raman transitions to realize a single-photon source with a tunable frequency and bandwidth in a diamond waveguide. Finally, we create entanglement between two SiV centers by detecting indistinguishable Raman photons emitted into a single waveguide. Entanglement is verified using a novel superradiant feature observed in photon correlation measurements, paving the way for the realization of quantum networks.
435 citations
TL;DR: The proof of concept allows the preparation of all-dielectric, rewritable SPhP resonators without the need for complex fabrication methods and foresee application potential for switchable infrared nanophotonic elements, for example, imaging elements such as superlenses and hyperlenses, as well as reconfigurable metasurfaces and sensors.
Abstract: Optically rewritable surface phonon–polariton resonators are demonstrated in a system combining phase-change materials that can reversibly switch between amorphous and crystalline phases, with polar crystals that support surface phonon–polaritons.
316 citations
01 Jan 2016
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299 citations
TL;DR: The switch fabric is composed of 56 2 × 2 silicon Mach-Zehnder interferometers, with each integrated with a pair of TiN resistive micro-heaters and a p-i-n diode, and the switching functionality is verified by transmission of 20 Gb/s on-off keying and 50 GB/s quadrature phase-shift keying optical signals.
Abstract: We experimentally demonstrate a 16 × 16 non-blocking optical switch fabric with a footprint of 10.7 × 4.4 mm2. The switch fabric is composed of 56 2 × 2 silicon Mach-Zehnder interferometers (MZIs), with each integrated with a pair of TiN resistive micro-heaters and a p-i-n diode. The average on-chip insertion loss at 1560 nm wavelength is ~6.7 dB and ~14 dB for the "all-cross" and "all-bar" states, respectively, with a loss variation of ± 1 dB over all routing paths. The measured rise/fall time of the switch upon electrical tuning is 3.2/2.5 ns. The switching functionality is verified by transmission of 20 Gb/s on-off keying (OOK) and 50 Gb/s quadrature phase-shift keying (QPSK) optical signals.
184 citations
TL;DR: A low-loss and broadband silicon thermo-optic switch is proposed and demonstrated experimentally by using a Mach-Zehnder Interferometer with 2×2 3 dB power splitters based on bent directional couplers (DCs), which shows excellent reproducibility and good fabrication tolerance, which makes it promising for realizing N×N optical switches.
Abstract: A low-loss and broadband silicon thermo-optic switch is proposed and demonstrated experimentally by using a Mach-Zehnder Interferometer with 2×2 3 dB power splitters based on bent directional couplers (DCs). The bent DCs are introduced here to replace the traditional 2×2 3 dB power splitters based on multimode interferometers or straight DCs, so that one achieves a coupling ratio of ∼50%∶ 50%, as well as low excess loss over a broadband. The demonstrated Mach-Zehnder switch (MZS) has a ∼140 nm bandwidth for an excess loss of 20 dB. The present MZS also shows excellent reproducibility and good fabrication tolerance, which makes it promising for realizing N×N optical switches.
155 citations
TL;DR: In this paper, a novel optical 4 × 2 encoder based on 2D square lattice photonic crystals of silicon rods is proposed, where the main realization of optical encoder is based on the photonic crystal ring resonator NOR gates.
Abstract: The photonic crystals draw significant attention to build all-optical logic devices and are considered one of the solutions for the opto-electronic bottleneck via speed and size. The paper presents a novel optical 4 × 2 encoder based on 2D square lattice photonic crystals of silicon rods. The main realization of optical encoder is based on the photonic crystal ring resonator NOR gates. The proposed structure has four logic input ports, two output ports, and two bias input port. The photonic crystal structure has a square lattice of silicon rods with a refractive index of 3.39 in air. The structure has lattice constant ‘a’ equal to 630 nm and bandgap range from 0.32 to 044. The total size of the proposed 4 × 2 encoder is equal to 35 μm × 35 μm. The simulation results using the dimensional finite difference time domain and Plane Wave Expansion methods confirm the operation and the feasibility of the proposed optical encoder for ultrafast optical digital circuits.
134 citations
TL;DR: Numerical simulation results indicate that the length difference between the upper waveguide and the under waveguide can change the output spectrum characteristics of the device, which acts like a Mach–Zehnder interferometer (MZI).
Abstract: We propose and demonstrate a directed optical logic circuit that can perform the XOR and XNOR logic operations consisting of two cascaded microring resonators, i.e., an upper waveguide and an under waveguide. No waveguide crossings exist in the circuit, which is very useful to improve the signal quality and reduce the insertion loss of the device. As proof of principle, XOR and XNOR logic operations with the speed of 10 kb/s are successfully demonstrated. In addition, numerical simulation results indicate that the length difference between the upper waveguide and the under waveguide can change the output spectrum characteristics of the device, which acts like a Mach–Zehnder interferometer (MZI).
127 citations
TL;DR: This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.
Abstract: The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.
124 citations
01 Aug 2016
TL;DR: This work presents a working implementation of a 4×4-port universal linear circuit implemented in silicon photonics, and demonstrates the circuit performing two distinct linear operations by changing the software algorithms that controls the circuit.
Abstract: We present our work on reconfigurable, general-purpose linear photonic circuits. Photonic integrated circuits today resemble the very specialized application specific integrated circuits (ASICs) rather than general-purpose CPUs or highly flexible field-programmable gate arrays (FPGA). Reprogrammable optical circuits could dramatically reduce the time to application or prototype a new optical chip. We will discuss the possibilities of such circuits, and present a working implementation of a 4×4-port universal linear circuit implemented in silicon photonics. We demonstrate the circuit performing two distinct linear operations by changing the software algorithms that controls the circuit.
106 citations
TL;DR: Here, picosecond all-optical switching of the local phase transition in plasmonic antenna-vanadium dioxide (VO2) hybrids is demonstrated, exploiting strong resonant field enhancement and selective optical pumping in plAsmonic hotspots.
Abstract: Nanoscale devices in which the interaction with light can be configured using external control signals hold great interest for next-generation optoelectronic circuits. Materials exhibiting a structural or electronic phase transition offer a large modulation contrast with multi-level optical switching and memory functionalities. In addition, plasmonic nanoantennas can provide an efficient enhancement mechanism for both the optically induced excitation and the readout of materials strategically positioned in their local environment. Here, we demonstrate picosecond all-optical switching of the local phase transition in plasmonic antenna-vanadium dioxide (VO2) hybrids, exploiting strong resonant field enhancement and selective optical pumping in plasmonic hotspots. Polarization- and wavelength-dependent pump-probe spectroscopy of multifrequency crossed antenna arrays shows that nanoscale optical switching in plasmonic hotspots does not affect neighboring antennas placed within 100 nm of the excited antennas. The antenna-assisted pumping mechanism is confirmed by numerical model calculations of the resonant, antenna-mediated local heating on a picosecond time scale. The hybrid, nanoscale excitation mechanism results in 20 times reduced switching energies and 5 times faster recovery times than a VO2 film without antennas, enabling fully reversible switching at over two million cycles per second and at local switching energies in the picojoule range. The hybrid solution of antennas and VO2 provides a conceptual framework to merge the field localization and phase-transition response, enabling precise, nanoscale optical memory functionalities.
TL;DR: In this paper, the authors demonstrate a path to integrate barium titanate thin films with strong Pockels coefficients into silicon photonic structures, and highlight various design options, discuss the actual fabrication process, and present experimental results of functional passive and active structures.
Abstract: Ultrafast and highly efficient optical modulators that are based on the Pockels effect are key components of today's optical communication networks. For the next generation of photonic links, silicon photonic technology is used to establish a new wave of densely integrated optic components. However, this new technology cannot exploit the advantages of using the Pockels effect for optical switching for two reasons: First, silicon does not exhibit any Pockels effect, and second, attempts to combine nonlinear materials with silicon photonics have been cumbersome. Here, we demonstrate a path to integrate barium titanate thin films with strong Pockels coefficients into silicon photonic structures. We highlight various design options, discuss the actual fabrication process, and present experimental results of functional passive and active structures. Examples include couplers and interferometers, as well as active, electrically driven nonvolatilely tunable ring resonators with a tunability of 4 μW/nm. Our results represent a major advancement in the field of ultralow-power silicon photonic switches based on nonlinear oxides, and demonstrate the potential of novel applications based on the hybrid barium titanate–silicon photonic platform.
TL;DR: It is shown that optoelectronic device performance scales non-monotonically with device length due to the various device tradeoffs, and how both optical and electrical constrains influence device power consumption and operating speed is analyzed.
Abstract: The success of information technology has clearly demonstrated that miniaturization often leads to unprecedented performance, and unanticipated applications. This hypothesis of “smaller-is-better” has motivated optical engineers to build various nanophotonic devices, although an understanding leading to fundamental scaling behavior for this new class of devices is missing. Here we analyze scaling laws for optoelectronic devices operating at micro and nanometer length-scale. We show that optoelectronic device performance scales non-monotonically with device length due to the various device tradeoffs, and analyze how both optical and electrical constrains influence device power consumption and operating speed. Specifically, we investigate the direct influence of scaling on the performance of four classes of photonic devices, namely laser sources, electro-optic modulators, photodetectors, and all-optical switches based on three types of optical resonators; microring, Fabry-Perot cavity, and plasmonic metal nanoparticle. Results show that while microrings and Fabry-Perot cavities can outperform plasmonic cavities at larger length-scales, they stop working when the device length drops below 100 nanometers, due to insufficient functionality such as feedback (laser), index-modulation (modulator), absorption (detector) or field density (optical switch). Our results provide a detailed understanding of the limits of nanophotonics, towards establishing an opto-electronics roadmap, akin to the International Technology Roadmap for Semiconductors.
TL;DR: This work controls the optical Stark shift of two energetically separated exciton states by applying a linearly polarized laser pulse to few-layer ReS2, where reduced symmetry leads to strong in-plane anisotropy of excitons.
Abstract: The optical Stark effect is a coherent light-matter interaction describing the modification of quantum states by non-resonant light illumination in atoms, solids and nanostructures. Researchers have strived to utilize this effect to control exciton states, aiming to realize ultra-high-speed optical switches and modulators. However, most studies have focused on the optical Stark effect of only the lowest exciton state due to lack of energy selectivity, resulting in low degree-of-freedom devices. Here, by applying a linearly polarized laser pulse to few-layer ReS2, where reduced symmetry leads to strong in-plane anisotropy of excitons, we control the optical Stark shift of two energetically separated exciton states. Especially, we selectively tune the Stark effect of an individual state with varying light polarization. This is possible because each state has a completely distinct dependence on light polarization due to different excitonic transition dipole moments. Our finding provides a methodology for energy-selective control of exciton states.
TL;DR: This paper introduces the basics of ROF communication, including optical modulation, the optical channel, and the optical detection techniques, and surveys the family of advanced optical upconversion techniques that exploit the nonlinearity of the ROF link.
Abstract: A study of advanced upconversion techniques used in radio over fiber (ROF) is provided. With the huge increase in both the number of wireless communication subscribers and the bandwidth required per customer, migrating to higher frequencies, i.e., from lower radio frequency to millimeter-wave carriers, is an essential solution. However, due to the short propagation range of millimeter waves, a large number of radio access points are required for providing reliable coverage, which would increase the infrastructure costs. Hence, the transmission of RF signals between the central (or control) points and radio access points (or remote antenna units) using optical fibers is one of the major access network solutions that have been proposed for future high-bandwidth wireless communication systems. In this paper, we introduce the basics of ROF communication, including optical modulation, the optical channel, and the optical detection techniques. Then we survey the family of advanced optical upconversion techniques that exploit the nonlinearity of the ROF link. Specifically, we describe how optical upconversion can be achieved by exploiting the Mach–Zehnder modulator's nonlinearity, wavelength conversion techniques, or the photodetector's nonlinearity. The wavelength conversion techniques rely on the nonlinearities present in the fiber, in the optical amplifier, or in the electroabsorption modulator.
TL;DR: In this article, the erasure of antiferromagnetic domains in multiferroic TbMnO3 using light pulses of two different colours is demonstrated using laser-controlled writing and erasure.
Abstract: Laser-controlled writing and erasure of antiferromagnetic domains in multiferroic TbMnO3 using light pulses of two different colours is demonstrated.
01 Aug 2016
TL;DR: In this article, the authors predict unity-order changes in the transmission and absorption of vis-NIR light produced upon electrical doping of graphene sheets coupled to realistically engineered optical cavities.
Abstract: Fast modulation and switching of light at visible and near-infrared (vis-NIR) frequencies is of utmost importance for optical signal processing and sensing technologies. No fundamental limit appears to prevent us from designing wavelength-sized devices capable of controlling the light phase and intensity at terahertz speeds in those spectral ranges. However, this problem remains largely unsolved, despite recent advances in the use of quantum wells and phase-change materials for that purpose. Here, we explore an alternative solution based upon the remarkable electro-optical properties of graphene. In particular, we predict unity-order changes in the transmission and absorption of vis-NIR light produced upon electrical doping of graphene sheets coupled to realistically engineered optical cavities. The light intensity is enhanced at the graphene plane, and so is its absorption, which can be switched and modulated via Pauli blocking through varying the level of doping. Specifically, we explore dielectric planar cavities operated under either tunneling or Fabry-Perot resonant transmission conditions, as well as Mie modes in silicon nanospheres and lattice resonances in metal particle arrays. Our simulations reveal absolute variations in transmission exceeding 90% using feasible material parameters, thus supporting the application of graphene in fast electro-optics at vis-NIR frequencies.
TL;DR: In this article, the structural and optical properties of ZnO thin films were investigated by using pulsed laser deposition technique on quartz substrates, and the results indicated that the substrate temperature strongly affected nonlinear optical properties and the values of third order nonlinear susceptibilities were found to be high enough for the potential applications in the optical switching devices.
TL;DR: The proposed Fano resonance is a most promising candidate for high on/off ratio optical switching/modulating, high-sensitivity biochemical sensing and can be periodically tuned via changing the resonant wavelengths of two resonators through the thermo-optic effect.
Abstract: We experimentally demonstrate a tunable Fano resonance which originates from the optical interference between two different resonant cavities using silicon micro-ring resonator with feedback coupled waveguide fabricated on silicon-on-insulator (SOI) substrate. The resonance spectrum can be periodically tuned via changing the resonant wavelengths of two resonators through the thermo-optic effect. In addition to this, we can also change the transmission loss of the feedback coupled waveguide (FCW) to tune the resonance spectrum by the injection free carriers to FCW. We also build the theoretical model and we analyze the device performance by using the scattering matrix method. The simulation results are in a good agreement with the experimental results. The measurement maximum extinction ratio of the Fano resonance is as high as 30.8dB. Therefore, the proposed device is a most promising candidate for high on/off ratio optical switching/modulating, high-sensitivity biochemical sensing.
TL;DR: Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate that activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-inf infrared spectral range.
Abstract: Impulsive interband excitation with femtosecond near-infrared pulses establishes a plasma response in intrinsic germanium structures fabricated on a silicon substrate. This direct approach activates the plasmonic resonance of the Ge structures and enables their use as optical antennas up to the mid-infrared spectral range. The optical switching lasts for hundreds of picoseconds until charge recombination redshifts the plasma frequency. The full behavior of the structures is modeled by the electrodynamic response established by an electron-hole plasma in a regular array of antennas.
TL;DR: The current status in InP integrated photonics for optical switch matrices is reviewed, paying particular attention to the additional on-chip functions that become feasible with active component integration.
Abstract: Integrated circuit technologies are enabling intelligent, chip-based, optical packet switch matrices. Rapid real-time re-configurability at the photonic layer using integrated circuit technologies is expected to enable cost-effective, energy-efficient, and transparent data communications. InP integrated photonic circuits offer high-performance amplifiers, switches, modulators, detectors, and de/multiplexers in the same wafer-scale processes. The complexity of these circuits has been transformed as the process technologies have matured, enabling component counts to increase to many hundreds per chip. Active–passive monolithic integration has enabled switching matrices with up to 480 components, connecting 16 inputs to 16 outputs. Integrated switching matrices route data streams of hundreds of gigabits per second. Multi-path and packet time-scale switching have been demonstrated in the laboratory to route between multiple fibre connections. Wavelength-granularity routing and monitoring is realised inside the chip. In this paper, we review the current status in InP integrated photonics for optical switch matrices, paying particular attention to the additional on-chip functions that become feasible with active component integration. We highlight the opportunities for introducing intelligence at the physical layer and explore the requirements and opportunities for cost-effective, scalable switching. Devices that can quickly redirect incoming packets of optically encoded data could substantially increase the speed of the Internet. Kevin Williams and colleagues have reviewed recent developments in large optical switch matrices with a particular focus on the work performed using Indium phosphide integrated photonics at the Eindhoven University of Technology in the Netherlands. Indium phosphide is a semiconducting material that can efficiently produce and amplify light. Optically active switches made from a single material can improve operation speed and reduce the optical and electrical energy consumption of the device. Thus, indium phosphide integrated photonic circuits can combine advanced routing and signal processing functions all on one chip. So far this technology has created switching matrices with up to 480 components, connecting sixteen inputs to sixteen outputs and routed data streams at rates of a few hundred Gigabits per second.
NEC1
TL;DR: In this article, the authors demonstrate compact and low-loss $8 \times 8$ silicon photonic switch modules, which are applicable to transponder aggregators (TPAs) in colorless, directionless, and contentionless reconfigurable optical add-drop multiplexers.
Abstract: We demonstrate compact and low-loss $8 \times 8$ silicon photonic switch modules, which are applicable to transponder aggregators (TPAs) in colorless, directionless, and contentionless reconfigurable optical add-drop multiplexers. Newly designed silicon optical switch chips incorporating spot size converters with polarization insensitive and wavelength insensitive properties over C/L bands are packaged. The developed module shows about 6-dB average excess optical loss, including optical coupling loss, on all 64 optical paths with low-polarization-dependent loss and low crosstalk. Using these compact optical switch modules, we construct a TPA prototype featuring over 100-port optical switch subsystem densely mounted on one board and confirm its feasibility.
TL;DR: In this article, the authors investigated functional integrated optic devices based on the specialties of fluorinated polymer material, which include extremely low crosstalk integrated optics, strain-controlled flexible waveguide tunable lasers, and birefringence-tuned polarization controllers.
TL;DR: Automatic reconfiguration and feedback controlled routing is demonstrated in an 8 × 8 silicon photonic switch fabric based on Mach-Zehnder interferometers, making the switch fabric robust against thermal crosstalk, even in the absence of a cooling system for the silicon chip.
Abstract: Automatic reconfiguration and feedback controlled routing is demonstrated in an $8 \times 8$ silicon photonic switch fabric based on Mach–Zehnder interferometers. The use of noninvasive contactless integrated photonic probes (CLIPPs) enables real-time monitoring of the state of each switching element individually. Local monitoring provides direct information on the routing path, allowing an easy sequential tuning and feedback controlled stabilization of the individual switching elements, thus making the switch fabric robust against thermal crosstalk, even in the absence of a cooling system for the silicon chip. Up to 24 CLIPPs are interrogated by a multichannel integrated ASIC wire bonded to the photonic chip. Optical routing is demonstrated on simultaneous WDM input signals that are labeled directly on-chip by suitable pilot tones without affecting the quality of the signals. Neither preliminary circuit calibration nor lookup tables are required, being the proposed control scheme inherently insensible to channels power fluctuations.
TL;DR: In this article, the authors demonstrate a 16×16 reconfigurable nonblocking optical switch fabric using a Benes architecture, which consists of 56 2×2 Mach-Zehnder interferometer based elementary switches, with each integrated with a pair of waveguide microheaters.
Abstract: We experimentally demonstrate a 16×16 reconfigurably nonblocking optical switch fabric using a Benes architecture. The switch fabric consists of 56 2×2 Mach–Zehnder interferometer based elementary switches, with each integrated with a pair of waveguide microheaters. The average on-chip insertion loss is ∼5.2 dB for both of the “all-cross” and the “all-bar” states, with a loss variation of 1 dB over all routing paths. The cross talk for all switching states is better than −30 dB. The switching time of the switch element is about 22 μs. The switching functionality is verified by transmission of a 40 Gb/s quadrature phase-shift keying optical signal.
TL;DR: A novel all-optical flat DCN architecture OPSquare is presented that potentially addresses the scaling issues by employing parallel intra-/inter-cluster switching networks, distributed fast WDM optical cross-connect (OXC) switches, and a novel top-of-rack (ToR) switch architecture.
Abstract: Scaling the capacity while maintaining low latency and power consumption is a challenge for hierarchical data center networks (DCNs) based on electrical switches. In this work we present a novel all-optical flat DCN architecture OPSquare that potentially addresses the scaling issues by employing parallel intra-/inter-cluster switching networks, distributed fast WDM optical cross-connect (OXC) switches, and a novel top-of-rack (ToR) switch architecture. The fast (nanoseconds) WDM OXC switches allow flexible switching capability in both wavelength and time domains and statistical multiplexing. The OPSquare DCN performance targeting Petabit/s capacity has been thoroughly assessed. First the packet loss, latency, throughput, and scalability are numerically investigated under realistic data center traffic model. Results indicate that when scaling the DCN size up to 1024 ToR switches, a packet loss ratio below 10−6 and a server end-to-end latency lower than 2 µs can be guaranteed at load of 0.3 with limited 20 kB buffer. Then, the experimental evaluation of the DCN by employing 4 × 4 OXC prototypes shows multi-path dynamic switching with flow control operation. The case deploying 32 × 32 and 64 × 64 OXC switches connecting 1024 and 4096 ToRs are emulated and limited performance degradation has been observed. The potential of switching higher-order modulation and waveband signals further proves the suitability of OPSquare architecture for Petabit/s and low-latency DCN by using optical switches with moderate radix.
TL;DR: A drastic power consumption reduction of around 90% has been demonstrated and very fast switching times of only 1.19 µs have also been achieved.
Abstract: Optical switches based on tunable multimode interference (MMI) couplers can simultaneously reduce the footprint and increase the tolerance against fabrication deviations. Here, a compact 2x2 silicon switch based on a thermo-optically tunable MMI structure with a footprint of only 0.005 mm(2) is proposed and demonstrated. The MMI structure has been optimized using a silica trench acting as a thermal isolator without introducing any substantial loss penalty or crosstalk degradation. Furthermore, the electrodes performance have significantly been improved via engineering the heater geometry and using two metallization steps. Thereby, a drastic power consumption reduction of around 90% has been demonstrated yielding to values as low as 24.9 mW. Furthermore, very fast switching times of only 1.19 µs have also been achieved.
TL;DR: Simulation results show that significant bandwidth savings in elastic filterless networks can be achieved compared with the fixed-grid filterless solutions, and two efficient RSA heuristics are also proposed to achieve suboptimal solutions for larger networks in reasonable time.
Abstract: Elastic optical networking is considered a promising candidate to improve the spectral efficiency of optical networks. One of the most important planning challenges of elastic optical networks is the NP-hard routing and spectrum assignment (RSA) problem. In this paper, we investigate offline RSA in elastic filterless optical networks, which use a passive broadcast-and-select architecture to offer network agility. Here, an elastic optical network is referred to as the optical network that can adapt the channel bandwidth, data rate, and transmission format for each traffic demand in order to offer maximum throughput. In elastic filterless networks, the presence of unfiltered signals resulting from the drop-and-continue node architecture must be considered as an additional constraint in the RSA problem. In this paper, first, the RSA problem in elastic filterless networks is formulated by using an integer linear program to obtain optimal solutions for small networks. Due to the problem complexity, two efficient RSA heuristics are also proposed to achieve suboptimal solutions for larger networks in reasonable time. Simulation results show that significant bandwidth savings in elastic filterless networks can be achieved compared with the fixed-grid filterless solutions. The proposed approach is further tested in multi-period traffic scenarios and combined with periodical spectrum defragmentation, leading to additional improvement in spectrum utilization of elastic filterless optical networks.
TL;DR: This paper aims to present the design and the achieved results on a CMOS electronic and photonic integrated device for low cost, low power, transparent, mass-manufacturable optical switching.
Abstract: This paper aims to present the design and the achieved results on a CMOS electronic and photonic integrated device for low cost, low power, transparent, mass-manufacturable optical switching. An unprecedented number of integrated photonic components (more than 1000), each individually electronically controlled, allows for the realization of a transponder aggregator device which interconnects up to eight transponders to a four direction colorless-directionless-contentionless ROADM. Each direction supports 12 200-GHz spaced wavelengths, which can be independently added or dropped from the network. An electronic ASIC, 3-D integrated on top of the photonic chip, controls the switch fabrics to allow a complete and microsecond fast reconfigurability.
TL;DR: In this article, a III-V photonic crystal (PhC) nanocavity, heterogeneously integrated on a silicon-on-insulator platform, is shown to be capable of exhibiting two elementary static random access memory (SRAM) cell functions individually, namely switching and latching operations under a high-speed, bitlevel regime.
Abstract: Heterogeneous integration of III-V semiconductors on silicon has gained considerable momentum fueled by the need to implement fully functional photonic devices and circuits in a CMOS compatible platform. In this communication, we report on a III-V photonic crystal (PhC) nanocavity, heterogeneously integrated on a silicon-on-insulator platform, to form a PhC nanocavity laser capable of exhibiting two elementary static random access memory (SRAM) cell functions individually, namely switching and latching operations under a high-speed, bit-level regime. As such, the PhC nanocavity laser is examined as a generic logic functions building block, suitable toward multiGb/s energy-efficient, optical SRAM cells with minimal device footprint. The proposed device occupies a total area of only 6.2 μm2 , rendering in this way the demonstrated memory element the smallest among the integrated optical memories presented so far. Bit-level SRAM cell operation requires two elementary functions: the access gate (AG) switching function and set-reset flip-flop (SR-FF) latching function. At first, AG switching operation is evaluated through successful wavelength conversion at 10 Gb/s, revealing a power penalty of 1 dB at 10–9 BER and a switching energy of only 4.8 fJ/bit. Then, fully functional SR-FF memory operation is successfully demonstrated, exhibiting error-free operation with negative power penalty at 5 Gb/s and switching energies of 6.4 fJ/bit. FF operation at higher speeds of 10 Gb/s with reduced switching energy levels of 3.2 fJ/bit is also experimentally investigated. Both logic operations were demonstrated separately with the same PhC nanocavity laser device exhibiting <50 ps switching times and evaluated under real-type data traffic patterns, raising expectations for beyond 20 Gb/s capabilities toward implementing energy-efficient, ultracompact and high-speed true optical SRAM setups for Datacom applications.