Showing papers on "Optical switch published in 2017"

Nonlinear photonic metasurfaces

Abstract: Compared with conventional optical elements, 2D photonic metasurfaces, consisting of arrays of antennas with subwavelength thickness (the ‘meta-atoms’), enable the manipulation of light–matter interactions on more compact platforms. The use of metasurfaces with spatially varying arrangements of meta-atoms that have subwavelength lateral resolution allows control of the polarization, phase and amplitude of light. Many exotic phenomena have been successfully demonstrated in linear optics; however, to meet the growing demand for the integration of more functionalities into a single optoelectronic circuit, the tailorable nonlinear optical properties of metasurfaces will also need to be exploited. In this Review, we discuss the design of nonlinear photonic metasurfaces — in particular, the criteria for choosing the materials and symmetries of the meta-atoms — for the realization of nonlinear optical chirality, nonlinear geometric Berry phase and nonlinear wavefront engineering. Finally, we survey the application of nonlinear photonic metasurfaces in optical switching and modulation, and we conclude with an outlook on their use for terahertz nonlinear optics and quantum information processing. Photonic metasurfaces can be used to control the polarization, phase and amplitude of light. Nonlinear metasurfaces enable giant nonlinear optical chirality, realization of the geometric Berry phase, wavefront engineering, and optical switching and modulation, and hold potential for on-chip applications.

A robust and tuneable mid-infrared optical switch enabled by bulk Dirac fermions

Abstract: Pulsed lasers operating in the mid-infrared (3–20 μm) are important for a wide range of applications in sensing, spectroscopy, imaging and communications. Despite recent advances with mid-infrared gain platforms, the lack of a capable pulse generation mechanism remains a significant technological challenge. Here we show that bulk Dirac fermions in molecular beam epitaxy grown crystalline Cd3As2, a three-dimensional topological Dirac semimetal, constitutes an exceptional ultrafast optical switching mechanism for the mid-infrared. Significantly, we show robust and effective tuning of the scattering channels of Dirac fermions via an element doping approach, where photocarrier relaxation times are found flexibly controlled over an order of magnitude (from 8 ps to 800 fs at 4.5 μm). Our findings reveal the strong impact of Cr doping on ultrafast optical properties in Cd3As2 and open up the long sought parameter space crucial for the development of compact and high-performance mid-infrared ultrafast sources. Mid-infrared pulsed sources are technologically important for sensing and spectroscopy but their implementation is challenging due to the lack of a tuneable optical switch. Here, the authors address this limitation by engineering the band structure of an emerging Dirac semimetal, Cd3As2.

RotorNet: A Scalable, Low-complexity, Optical Datacenter Network

Abstract: The ever-increasing bandwidth requirements of modern datacenters have led researchers to propose networks based upon optical circuit switches, but these proposals face significant deployment challenges. In particular, previous proposals dynamically configure circuit switches in response to changes in workload, requiring network-wide demand estimation, centralized circuit assignment, and tight time synchronization between various network elements--- resulting in a complex and unwieldy control plane. Moreover, limitations in the technologies underlying the individual circuit switches restrict both the rate at which they can be reconfigured and the scale of the network that can be constructed.We propose RotorNet, a circuit-based network design that addresses these two challenges. While RotorNet dynamically reconfigures its constituent circuit switches, it decouples switch configuration from traffic patterns, obviating the need for demand collection and admitting a fully decentralized control plane. At the physical layer, RotorNet relaxes the requirements on the underlying circuit switches---in particular by not requiring individual switches to implement a full crossbar---enabling them to scale to 1000s of ports. We show that RotorNet outperforms comparably priced Fat Tree topologies under a variety of workload conditions, including traces taken from two commercial datacenters. We also demonstrate a small-scale RotorNet operating in practice on an eight-node testbed.

A Novel Proposal for All Optical Analog-to-Digital Converter Based on Photonic Crystal Structures

Abstract: In this paper, we proposed a novel all optical analog-to-digital (ADC) converter based on photonic crystals. First of all, we designed a three port nonlinear demultiplexer, for producing discrete levels of input optical intensity. Then, an optical coder was used to generate a 2-bit standard binary code out of the discrete levels coming from the nonlinear demultiplexer. The final structure was realized by combining the nonlinear demultiplexer with the optical coder. The maximum sampling rate of the proposed structure obtained to be about 200 GS/s, and the total footprint is about 806 μm2.

Current-driven phase-change optical gate switch using indium–tin-oxide heater

Abstract: We proposed and fabricated a current-driven phase-change optical gate switch using a Ge2Sb2Te5 (GST225) thin film, an indium–tin-oxide (ITO) heater, and a Si waveguide. Microfabrication technology compatible with CMOS fabrication was used for the fabrication of the Si waveguide. The repetitive phase changing of GST225 was obtained by injecting a current pulse into the ITO heater beneath the GST225 thin film. The switching operation was observed by injecting a 100-ns current pulse of 20 mA into the ITO heater. The average extinction ratio over the wavelength range of 1,525 to 1,625 nm was 1.2 dB.

Deterministic all-optical switching of synthetic ferrimagnets using single femtosecond laser pulses

Abstract: We experimentally demonstrate single-pulse all-optical switching in Pt/Co/Gd stacks using linearly polarized laser pulses. This shows that thermal single-pulse switching is not limited to ferrimagnetic alloys, but is also possible in ferrimagnetic multilayers that are highly suitable for future applications due to easy fabrication and (interface) engineering. Moreover, it is shown that the threshold fluence needed for the optical switch strongly depends on the thickness of the Co layer, with a remarkable low threshold fluence of $\ensuremath{\approx}1.2$ mJ/${\mathrm{cm}}^{2}$ for a Co thickness of 0.8 nm. Lastly, helicity-dependent measurements showed no significant effect of the magnetic circular dichroism in these thin magnetic layers.

A Solution-Processed Ultrafast Optical Switch Based on a Nanostructured Epsilon-Near-Zero Medium

Abstract: All the optical properties of materials are derived from dielectric function. In spectral region where the dielectric permittivity approaches zero, known as epsilon-near-zero (ENZ) region, the propagating light within the material attains a very high phase velocity, and meanwhile the material exhibits strong optical nonlinearity. The interplay between the linear and nonlinear optical response in these materials thus offers unprecedented pathways for all-optical control and device design. Here the authors demonstrate ultrafast all-optical modulation based on a typical ENZ material of indium tin oxide (ITO) nanocrystals (NCs), accessed by a wet-chemistry route. In the ENZ region, the authors find that the optical response in these ITO NCs is associated with a strong nonlinear character, exhibiting sub-picosecond response time (corresponding to frequencies over 2 THz) and modulation depth up to ≈160%. This large optical nonlinearity benefits from the highly confined geometry in addition to the ENZ enhancement effect of the ITO NCs. Based on these ENZ NCs, the authors successfully demonstrate a fiber optical switch that allows switching of continuous laser wave into femtosecond laser pulses. Combined with facile processibility and tunable optical properties, these solution-processed ENZ NCs may offer a scalable and printable material solution for dynamic photonic and optoelectronic devices.

Silicon Nanophotonic Integrated Devices for On-Chip Multiplexing and Switching

Abstract: A review is given on our recent progresses in silicon nanophotonic integrated devices for multiplexing and switching, which are key elements in a multichannel multiplexed photonic networks-on-chip. On-chip (de)multiplexers include wavelength-division-multiplexing filters based on arrayed-waveguide gratings and microring resonators, polarization-division-multiplexing devices like polarizers, polarization-beam splitters and polarization rotators, mode-division-multiplexing devices, and some novel hybrid (de)multiplexers enabling more than one multiplexing technologies simultaneously. Thermal-switchable silicon photonic devices are also discussed regarding the increasing demands for reconfigurable photonic networks-on-chip, including high-performance optical switches and reconfigurable add-drop multiplexers.

High-speed two-mode switch for mode-division multiplexing optical networks

Abstract: Mode-division multiplexing technology using the high-order modes of multimode waveguides enables high-bandwidth data transmission. High-speed mode channel switching is a pivotal function for these optical networks. Here, we propose a modal switching scheme on a silicon-on-insulator platform and demonstrate a high-speed two-mode switch that exploits a Y-junction and multimode interference structure. The design allows for simultaneous switching of two optical modes. A PN-doped junction-based phase shifter in one branch of a Y-junction enables dynamic switching in 2.5 ns. The measured switching extinction ratio is 12.5 dB or better with an open eye diagram for a 10 Gb/s on–off key optical payload signal. The optical power penalty is within 0.5 dB for the two-mode switching at a bit error rate of 10−9. This two-mode switch could enable on-chip mode-based switching network topology for greater aggregated throughput capacity.

Study the role of non-linear resonant cavities in photonic crystal-based decoder switches

Abstract: In this paper, we are going to design and propose a novel structure for all optical decoder. The proposed structure is composed of optical power splitters and a four-port optical switch. The four-port optical switch simply is a non-linear optical demulitiplexer. For achieving non-linear behaviour for the demultiplexer, we will employ defect rods made of doped glass which has high Kerr coefficient. The final structure has three input ports and four output ports. Port E acts as enable port, which will be used activating or deactivating the total structure. A and B are the control ports, by which one can control when the structure is active, which port of the structure to be active. The optical intensity of the input ports required appropriate operation of the structure is about 20 W/μm2. The maximum switching frequency of the proposed structure is 2 GHz. Reduced input optical intensity is the main characteristics of the present work. Numerical methods such as plane wave expansion and finite differen...

Photon-triggered nanowire transistors.

Abstract: Porous silicon nanowires enable optical switching and electrical current amplification in a photon-triggered transistor. Photon-triggered electronic circuits have been a long-standing goal of photonics. Recent demonstrations include either all-optical transistors in which photons control other photons1,2 or phototransistors with the gate response tuned or enhanced by photons3,4,5. However, only a few studies report on devices in which electronic currents are optically switched and amplified without an electrical gate. Here we show photon-triggered nanowire (NW) transistors, photon-triggered NW logic gates and a single NW photodetection system. NWs are synthesized with long crystalline silicon (CSi) segments connected by short porous silicon (PSi) segments. In a fabricated device, the electrical contacts on both ends of the NW are connected to a single PSi segment in the middle. Exposing the PSi segment to light triggers a current in the NW with a high on/off ratio of >8 × 106. A device that contains two PSi segments along the NW can be triggered using two independent optical input signals. Using localized pump lasers, we demonstrate photon-triggered logic gates including AND, OR and NAND gates. A photon-triggered NW transistor of diameter 25 nm with a single 100 nm PSi segment requires less than 300 pW of power. Furthermore, we take advantage of the high photosensitivity and fabricate a submicrometre-resolution photodetection system. Photon-triggered transistors offer a new venue towards multifunctional device applications such as programmable logic elements and ultrasensitive photodetectors.

All-Optical Switching of Magnetic Tunnel Junctions with Single Subpicosecond Laser Pulses

Abstract: Injecting charge or spin current can switch the magnetization in a spintronic device without an applied magnetic field, at a speed limited by spin precession. Optical switching can beat this limit, but has been achieved only in single magnetic layers, not full devices. The authors demonstrate switching in magnetic tunnel junctions (MTJs), the building blocks of spintronic technology, with 0.4-ps infrared laser pulses. Their junctions use Gd-Fe-Co alloy, which after being heated by a pulse spontaneously relaxes to the opposite magnetic state---at 100 times the record speed for MTJ switching.

A 40-Gb/s PAM-4 Transmitter Based on a Ring-Resonator Optical DAC in 45-nm SOI CMOS

Abstract: The next generations of large-scale data-centers and supercomputers demand optical interconnects to migrate to 400G and beyond. Microring modulators in silicon-photonics VLSI chips are promising devices to meet this demand due to their energy efficiency and compatibility with dense wavelength division multiplexed chip-to-chip optical I/O. Higher order pulse amplitude modulation (PAM) schemes can be exploited to mitigate their fundamental energy–bandwidth tradeoff at the system level for high data rates. In this paper, we propose an optical digital-to-analog converter based on a segmented microring resonator, capable of operating at 20 GS/s with improved linearity over conventional optical multi-level generators that can be used in a variety of applications such as optical arbitrary waveform generators and PAM transmitters. Using this technique, we demonstrate a PAM-4 transmitter that directly converts the digital data into optical levels in a commercially available 45-nm SOI CMOS process. We achieved 40-Gb/s PAM-4 transmission at 42-fJ/b modulator and driver energies, and 685-fJ/b total transmitter energy efficiency with an area bandwidth density of 0.67 Tb/s/mm2. The transmitter incorporates a thermal tuning feedback loop to address the thermal and process variations of microrings’ resonance wavelength. This scheme is suitable for system-on-chip applications with a large number of I/O links, such as switches and general-purpose and specialized processors in large-scale computing and storage systems.

Silicon waveguide optical switch with embedded phase change material.

Abstract: Phase-change materials (PCMs) have emerged as promising active elements in silicon (Si) photonic systems. In this work, we design, fabricate, and characterize a hybrid Si-PCM optical switch. By integrating vanadium dioxide (a PCM) within a Si photonic waveguide, in a non-resonant geometry, we achieve ~10 dB broadband optical contrast with a PCM length of 500 nm using thermal actuation.

Broadband silicon photonics 8 × 8 switch based on double-Mach-Zehnder element switches.

Abstract: We fabricated and characterized a silicon photonics 8 × 8 strictly non-blocking optical switch based on double-Mach–Zehnder (MZ) element switches. The double-MZ switches, each of which consisted of an intersection and two asymmetric MZ switches, enabled the suppression of crosstalk across a wide wavelength range. The 8 × 8 switch exhibited an average fiber-to-fiber insertion loss of 11.2 dB and -20 dB crosstalk in a bandwidth wider than 30 nm. Furthermore, we constructed an 8 × 8 polarization-diversity switch by using two 8 × 8 switches and demonstrated 32-Gbaud dual-polarization, quadrature-phase-shift-keying, four-channel wavelength-division-multiplexed signal transmission without significant signal degradation.

From Chip to Cloud: Optical Interconnects in Engineered Systems

Abstract: The high-performance server compute landscape is changing. The traditional model of building general-purpose enterprise compute boxes that end-users can configure with storage and networking to assemble their desired compute environments, has evolved to purpose-built systems optimized for specific applications. This tight integration of hardware and software components together with high-density midboard optical modules and an optical backplane allows for unprecedented levels of switching and compute efficiencies and has fueled the penetration of optical interconnects deep “inside the box,” particularly for switch scale-up. We briefly review earlier 40 G/port switching systems based on active optical cables, and present our newest system: An all-optically-interconnected 100 G/port 8.2 Tb/s InfiniBand packet switch ASIC with 41 ports running 100 Gb/s per port interconnected by 12-channel midboard optical transceivers with 25 Gb/s per channel per direction of optical I/O. Using a blind-mate optical backplane, these components enable systems with up to 50 Tb/s bandwidth in a 2U standard rack mount configuration with industry-leading density, efficiency, and latency. For even tighter co-integration of optical interconnects with switch and processor ASICs, we discuss photonic multichip module and interposer packaging technologies that will further improve system energy efficiencies and overcome impending system I/O bottlenecks.

Large-FSR Thermally Tunable Double-Ring Filters for WDM Applications in Silicon Photonics

Abstract: We present the design procedure and experimental results of thermally tunable double ring resonators for integrated wavelength division multiplexing applications. A detailed analytical model specific for double rings is described, and a modified racetrack geometry using Bezier bends is used to reduce bending loss. We demonstrate devices with a free-spectral-range up to 2.4 THz (19 nm) around 1550 nm and nonadjacent channel rejection higher than 35 dB. The experimental results of thermally tunable double ring resonators is also presented with doped silicon integrated heaters, allowing the device to be used as a tunable filter or a switch.

Sub-Shot-Noise Transmission Measurement Enabled by Active Feed-Forward of Heralded Single Photons

Abstract: Harnessing the unique properties of quantum mechanics offers the possibility of delivering alternative technologies that can fundamentally outperform their classical counterparts. These technologies deliver advantages only when components operate with performance beyond specific thresholds. For optical quantum metrology, the biggest challenge that impacts on performance thresholds is optical loss. Here, we demonstrate how including an optical delay and an optical switch in a feed-forward configuration with a stable and efficient correlated photon-pair source reduces the detector efficiency required to enable quantum-enhanced sensing down to the detection level of single photons and without postselection. When the switch is active, we observe a factor of improvement in precision of 1.27 for transmission measurement on a per-input-photon basis compared to the performance of a laser emitting an ideal coherent state and measured with the same detection efficiency as our setup. When the switch is inoperative, we observe no quantum advantage.

Optical switch compatible with wavelength division multiplexing and mode division multiplexing for photonic networks-on-chip

Abstract: We propose a 2 × 2 multimode optical switch, which is composed of two mode de-multiplexers, n 2 × 2 single-mode optical switches where n is the number of the supported spatial modes, and two mode multiplexers. As a proof of concept, asymmetric directional couplers are employed to construct the mode multiplexers and de-multiplexers, balanced Mach-Zehnder interferometer is utilized to construct the 2 × 2 single-mode optical switches. The fabricated silicon 2 × 2 multimode optical switch has a broad optical bandwidth and can support four spatial modes. The link-crosstalk for all four modes is smaller than −18.8 dB. The inter-mode crosstalk for the same optical link is less than −22.1 dB. 40 Gbps data transmission is performed for all spatial modes and all optical links. The power penalties for the error-free switching (BER<10−9) at 25 Gbps are less than 1.8 dB for all channels at the wavelength of 1550 nm. The power consumption of the device is 117.9 mW in the “cross” state and 116.2 mW in the “bar” state. The switching time is about 21 μs. This work enables large-capacity multimode photonic networks-on-chip.

Optical Switching Using Transition from Dipolar to Charge Transfer Plasmon Modes in Ge2Sb2Te5 Bridged Metallodielectric Dimers

Abstract: Capacitive coupling and direct shuttling of charges in nanoscale plasmonic components across a dielectric spacer and through a conductive junction lead to excitation of significantly different dipolar and charge transfer plasmon (CTP) resonances, respectively. Here, we demonstrate the excitation of dipolar and CTP resonant modes in metallic nanodimers bridged by phase-change material (PCM) sections, material and electrical characteristics of which can be controlled by external stimuli. Ultrafast switching (in the range of a few nanoseconds) between amorphous and crystalline phases of the PCM section (here Ge2Sb2Te5 (GST)) allows for designing a tunable plasmonic switch for optical communication applications with significant modulation depth (up to 88%). Judiciously selecting the geometrical parameters and taking advantage of the electrical properties of the amorphous phase of the GST section we adjusted the extinction peak of the dipolar mode at the telecommunication band (λ~1.55 μm), which is considered as the OFF state. Changing the GST phase to crystalline via optical heating allows for direct transfer of charges through the junction between nanodisks and formation of a distinct CTP peak at longer wavelengths (λ~1.85 μm) far from the telecommunication wavelength, which constitutes the ON state.

Optoelectronic Oscillator Based Sensor Using an On-Chip Sensing Probe

Abstract: An integrated photonic sensor based on an optoelectronic oscillator with an on-chip sensing probe that is capable of realizing highly sensitive and high-resolution optical sensing is presented. The key component is an integrated silicon-on-insulator based microring resonator which is used to implement a microwave photonic bandpass filter (MPBF) to effectively suppress the side modes of the optoelectronic oscillator (OEO) by more than 30 dB, thus generating a peak RF signal that maps the detected optical change into a resulting shift in the oscillating frequency. As an application example, the proposed optical sensor system is employed to detect small changes in temperature, and experimental results demonstrate a highly sensitive optical temperature sensor with an achieved sensitivity of 7.7 GHz/°C. Moreover, the proposed sensing system revealed a 0.02 °C measurement resolution, which is a tenfold improvement to the modest resolution of 0.23 °C of the conventional MPBF system without the OEO loop, rendering it highly suitable for diverse high-resolution sensing applications.

Universal dynamics and deterministic switching of dissipative Kerr solitons in optical microresonators

Abstract: The formation of dissipative Kerr solitons in optical microresonators enables fully coherent optical frequency combs with microwave repetition rates. Of particular interest is the single soliton state that exhibits a spectrally smooth sech2 profile imperative for applications such as coherent optical communications, coherent receivers and dual-comb spectroscopy. However, the generation process of such comb sources remains challenging and non-deterministic. In our work [1], we discovered a simple mechanism that deterministically switches the soliton state, allowing for the generation of single-soliton-based frequency combs. We demonstrated this control in both Si 3 N 4 and MgF 2 microresonators. Moreover, we observed a double-resonance feature in system's response to a pump modulation, an effect uniquely associated with the soliton regime. Our measurements provide insight into the soliton dynamics and reveal the physical mechanism of the soliton switching. The technique provides a method to monitor and stabilize the frequency comb state, in particular allowing for feedback stabilization of the single soliton state [2], which is necessary for applications.

Application of Waveguide/Free-Space Optics Hybrid to ROADM Device

Abstract: As optical networks have evolved from point-to-point systems to ring or mesh networks, the optical devices that are needed to construct optical nodes have become more important and need to be more scalable. Hybridization of waveguide and free-space optics, or spatial and planar optical circuits (SPOCs), may provide the solutions for such needs. An SPOC platform is attractive because it can take advantage of both waveguide technology and free-space optics. Waveguide technology provides a high degree of integration of optical functionality for devices such as splitters and non-wavelength selective switches while free-space optics supplies a high degree of parallelism with two-dimensional spatial light modulators such as a liquid crystal on silicon (LCOS) devices. In this paper, we summarize the basics of SPOC technology and review its application to reconfigurable optical add-drop multiplexing (ROADM) devices. The key elements of a waveguide on an SPOC platform are an arrayed-waveguide grating and a spatial beam transformer. The latter functions as a microlens array and provides attractive features such as dense integration of switches. An LCOS device has numerous phase modulating pixels, enabling flexible manipulation of lightwaves. Using an SPOC platform, we constructed and demonstrated devices for ROADM applications including a wavelength filter, tunable optical dispersion compensators, and wavelength selective switches (WSSs). The WSSs range from an ultrahigh port count WSS to a single module wavelength cross connect.

Nonlinear Black Phosphorus for Ultrafast Optical Switching

Abstract: The outstanding electronic and optical properties of black phosphorus (BP) in a two-dimensional (2D) but unique single-layer puckered structure have opened intense research interest ranging from fundamental physics to nanoscale applications covering the electronic and optical domains. The direct and controllable electronic bandgap facilitating wide range of tunable optical response coupled with high anisotropic in-plane properties made BP a promising nonlinear optical material for broadband optical applications. Here, we investigate ultrafast optical switching relying on the optical nonlinearity of BP. Wavelength conversion for modulated signals whose frequency reaches up to 20 GHz is realized by four-wave-mixing (FWM) with BP-deposited D-shaped fiber. In the successful demonstration of the FWM based wavelength conversion, performance parameter has been increased up to ~33% after employing BP in the device. It verifies that BP is able to perform efficient optical switching in the evanescent field interaction regime at very high speed. Our results might suggest that BP-based ultra-fast photonics devices could be potentially developed for broadband applications.

Reversible optical switching memristors with tunable STDP synaptic plasticity: a route to hierarchical control in artificial intelligent systems

Abstract: Optical control of memristors opens the route to new applications in optoelectronic switching and neuromorphic computing. Motivated by the need for reversible and latched optical switching we report on the development of a memristor with electronic properties tunable and switchable by wavelength and polarization specific light. The device consists of an optically active azobenzene polymer, poly(disperse red 1 acrylate), overlaying a forest of vertically aligned ZnO nanorods. Illumination induces trans–cis isomerization of the azobenzene molecules, which expands or contracts the polymer layer and alters the resistance of the off/on states, their ratio and retention time. The reversible optical effect enables dynamic control of a memristor's learning properties including control of synaptic potentiation and depression, optical switching between short-term and long-term memory and optical modulation of the synaptic efficacy via spike timing dependent plasticity. The work opens the route to the dynamic patterning of memristor networks both spatially and temporally by light, thus allowing the development of new optically reconfigurable neural networks and adaptive electronic circuits.

Recent Developments in Polymer-Based Photonic Components for Disruptive Capacity Upgrade in Data Centers

Abstract: Recently developed photonic components for next-generation datacenter systems based on the Heinrich Hertz Institute´s PolyBoard integration platform are reviewed. Hybrid-integrated transmitters and receivers, including optical functionalities, such as tunable lasers, polarization manipulators, 1 × 2 switches, and variable optical attenuators, are presented. The flexibility of those devices provides the possibility of generating, routing and detecting multiple optical data flows, offering the potential of aggregating traffics of 1 Tb/s and beyond. In addition, vertically stacked polymer waveguide structures are presented, opening the way towards the third dimension in photonic integration and allowing increasing the transmission capacity beyond the physical limit of standard single mode fibers. The freedom in the arrangement of the polymer waveguides allow for the matching of different multicore fiber types, providing the possibility of processing in parallel the different optical flows. By means of micromachining 45 $^{\circ}$ mirrors on the different stack levels, the three-dimensional (3-D) stacked waveguide structure can act as an interface between multicore fibers and planar optoelectronic devices such as photodiodes and laser diodes. Furthermore, a novel concept for a 4 × 4 3-D optical switch based on 3-D multimode interferometers is presented and numerically proven, showing potential for its application as the interface between multicore fibers and planar optoelectronic devices, as well as offering the possibility of reconfigurable N × N switching matrices.

Design of One-Bit Magnitude Comparator Using Nonlinear Plasmonic Waveguide

Abstract: The effective optical switching property of Mach–Zehnder interferometer (MZI) utilizing optical Kerr effect has been precisely reported suitably assisted with an analytical approach in this paper. MZI plays the role of the fundamental building block in the designing of intricate combinational circuit by employing Kerr effect. This paper constitutes ultra-compact design of one-bit magnitude comparator along with its mathematical analysis. The analysis of device is justified through MATLAB and finite-difference time-domain (FDTD) method.

Energy-performance optimized design of silicon photonic interconnection networks for high-performance computing

Abstract: We present detailed electrical and optical models of the elements that comprise a WDM silicon photonic link. The electronics is assumed to be based on 65 nm CMOS node and the optical modulators and demultiplexers are based on microring resonators. The goal of this study is to analyze the energy consumption and scalability of the link by finding the right combination of (number of channels × data rate per channel) that fully covers the available optical power budget. Based on the set of empirical and analytical models presented in this work, a maximum capacity of 0.75 Tbps can be envisioned for a point-to-point link with an energy consumption of 1.9 pJ/bit. Sub-pJ/bit energy consumption is also predicted for aggregated bitrates up to 0.35 Tbps.

Actively controllable terahertz switches with graphene-based nongroove gratings

Abstract: We systematically investigated the tunable dynamic characteristics of a broadband surface plasmon polariton (SPP) wave on a silicon-graded grating structure in the range of 10–40 THz with the aid of single-layer graphene. The theoretical and numerical simulated results demonstrate that the SPPs at different frequencies within a broadband range can be trapped at different positions on the graphene surface, which can be used as a broadband spectrometer and optical switch. Meanwhile, the group velocity of the SPPs can be modulated to be several hundred times smaller than light velocity in vacuum. Based on the theoretical analyses, we have predicted the trapping positions and corresponding group velocities of the SPP waves with different frequencies. By appropriately tuning the gate voltages, the trapped SPP waves can be released to propagate along the surface of graphene or out of the graded grating zone. Thus, we have also investigated the switching characteristics of the slow light system, where the optical switching can be controlled as an “off” or “on” mode by actively adjusting the gate voltage. The slow light system offers advantages, including broadband operation, ultracompact footprint, and tunable ability simultaneously, which holds great promise for applications in optical switches.