Showing papers on "Optical switch published in 2018"

Broadband Nonlinear Photonics in Few-Layer MXene Ti3C2Tx (T = F, O, or OH)

Abstract: Studies of the nonlinear optical phenomena that describe the light-matter interactions in 2D crystalline materials have promoted a diverse range of photonic applications. MXene, as a recently developed new 2D material, has attracted considerable attention because of its graphene-like but highly tunable and tailorable electronic/optical properties. In this study, we systematically characterize the nonlinear optical response of MXene Ti3C2Tx nanosheets over the spectral range of 800 nm to 1800 nm. A large effective nonlinear absorption coefficient (βeff∼-10−21 m2/V2) due to saturable absorption is observed for all of the testing wavelengths. The contribution of saturable absorption is two orders of magnitude higher than other lossy nonlinear absorption processes, and the amplitude of βeff strongly depends on the light bleaching level. A negative nonlinear refractive index (n2∼-10−20 m2/W) with value comparable to that of the intensively studied graphene was demonstrated for the first time. These results demonstrate the efficient broadband light signal manipulating capabilities of Ti3C2Tx, which is only one member of the large MXene family. The capability of an efficient broadband optical switch is strongly confirmed using Ti3C2Tx as saturable absorbers for mode-locking operation at 1066 nm and 1555 nm, respectively. A highly stable femtosecond laser with pulse duration as short as 159 fs in the telecommunication window is readily obtained. Considering the diversity of the MXene family, this study may open a new avenue to advanced photonic devices.

A Monolithically Integrated Large-Scale Optical Phased Array in Silicon-on-Insulator CMOS

Abstract: A large-scale monolithic silicon nanophotonic phased array on a chip creates and dynamically steers a high-resolution optical beam in free space, enabling emerging applications in sensing, imaging, and communication. The scalable architecture leverages sub-array structure, mitigating the impact of process variation on the phased array performance. In addition, sharing control electronics among multiple optical modulators in the scalable architecture reduces the number of digital-to-analog converters (DACs) required for an $N^{2}$ array from $\mathcal {O}(N^{2})$ to $\mathcal {O}(N)$ , allowing a small silicon footprint. An optical phased array for 1550-nm wavelength with 1024 uniformly spaced optical grating antennas, 1192 optical variable phase shifters, and 168 optical variable attenuators is integrated into a 5.7 mm $\times$ 6.4 mm chip in a commercial 180-nm silicon-on-insulator RF CMOS technology. The control signals for the optical variable phase shifters and attenuators are provided by 136 DACs with 14-bit nonuniform resolution using 2.5-V input-output transistors. The implemented phased array can create 0.03° narrow optical beams that can be steered unambiguously within ±22.5°.

GST-on-silicon hybrid nanophotonic integrated circuits: a non-volatile quasi-continuously reprogrammable platform

Abstract: Reconfiguration of silicon photonic integrated circuits relying on the weak, volatile thermo-optic or electro-optic effect of silicon usually suffers from a large footprint and energy consumption. Here, integrating a phase-change material, Ge2Sb2Te5 (GST) with silicon microring resonators, we demonstrate an energy-efficient, compact, non-volatile, reprogrammable platform. By adjusting the energy and number of free-space laser pulses applied to the GST, we characterize the strong broadband attenuation and optical phase modulation effects of the platform, and perform quasi-continuous tuning enabled by thermo-optically-induced phase changes. As a result, a non-volatile optical switch with a high extinction ratio, as large as 33 dB, is demonstrated.

Photonic switching in high performance datacenters [Invited]

Abstract: Photonic switches are increasingly considered for insertion in high performance datacenter architectures to meet the growing performance demands of interconnection networks. We provide an overview of photonic switching technologies and develop an evaluation methodology for assessing their potential impact on datacenter performance. We begin with a review of three categories of optical switches, namely, free-space switches, III-V integrated switches and silicon integrated switches. The state-of-the-art of MEMS, LCOS, SOA, MZI and MRR switching technologies are covered, together with insights on their performance limitations and scalability considerations. The performance metrics that are required for optical switches to truly emerge in datacenters are discussed and summarized, with special focus on the switching time, cost, power consumption, scalability and optical power penalty. Furthermore, the Pareto front of the switch metric space is analyzed. Finally, we propose a hybrid integrated switch fabric design using the III-V/Si wafer bonding technique and investigate its potential impact on realizing reduced cost and power penalty.

Ultracompact Si-GST Hybrid Waveguides for Nonvolatile Light Wave Manipulation

Abstract: Phase change materials (PCMs) combined with silicon photonics are emerging as a promising platform to realize miniature photonic devices. We study the basic optical properties of a sub-wavelength-dimension silicon ridge waveguide with a 20-nm-thick Ge2Sb2Te5 (GST) top-clad layer. Numerical simulations show that the effective index of the Si-GST hybrid waveguide varies significantly when the GST changes from the amorphous to the crystalline states. This change can be utilized to make micron-size photonic devices. To experimentally verify the effectiveness of the Si-GST hybrid waveguide on light wave manipulation, we fabricated a series of unbalanced Mach-Zehnder interferometers with one arm connected with a section of Si-GST hybrid waveguide in different lengths. The transmission spectra are measured and the complex effective indices are extracted for GST at crystalline, amorphous and intermediate phases. The experimental results overall agree well with the simulation ones. The nonvolatile property of GST makes it attractive to reduce the static power consumption. This research represents a significant step towards the realization of ultra-compact Si-GST hybrid devices that will play a key role in high-density photonic integrated circuits, opening the door to many potential applications, including optical switch, memory and logic operation.

Extreme Broadband Transparent Optical Phase Change Materials for High-Performance Nonvolatile Photonics

Abstract: Optical phase change materials (O-PCMs), a unique group of materials featuring drastic optical property contrast upon solid-state phase transition, have found widespread adoption in photonic switches and routers, reconfigurable meta-optics, reflective display, and optical neuromorphic computers. Current phase change materials, such as Ge-Sb-Te (GST), exhibit large contrast of both refractive index (delta n) and optical loss (delta k), simultaneously. The coupling of both optical properties fundamentally limits the function and performance of many potential applications. In this article, we introduce a new class of O-PCMs, Ge-Sb-Se-Te (GSST) which breaks this traditional coupling, as demonstrated with an optical figure of merit improvement of more than two orders of magnitude. The first-principle computationally optimized alloy, Ge2Sb2Se4Te1, combines broadband low optical loss (1-18.5 micron), large optical contrast (delta n = 2.0), and significantly improved glass forming ability, enabling an entirely new field of infrared and thermal photonic devices. We further leverage the material to demonstrate nonvolatile integrated optical switches with record low loss and large contrast ratio, as well as an electrically addressed, microsecond switched pixel level spatial light modulator, thereby validating its promise as a platform material for scalable nonvolatile photonics.

Ultrafast All-Optical Switching of Germanium-Based Flexible Metaphotonic Devices.

Abstract: Incorporating semiconductors as active media into metamaterials offers opportunities for a wide range of dynamically switchable/tunable, technologically relevant optical functionalities enabled by strong, resonant light-matter interactions within the semiconductor. Here, a germanium-thin-film-based flexible metaphotonic device for ultrafast optical switching of terahertz radiation is experimentally demonstrated. A resonant transmission modulation depth of 90% is achieved, with an ultrafast full recovery time of 17 ps. An observed sub-picosecond decay constant of 670 fs is attributed to the presence of trap-assisted recombination sites in the thermally evaporated germanium film.

General architectures for on-chip optical space and mode switching

Abstract: The optical switches for single-mode operation cannot be directly utilized in optical communication and interconnect systems adopting mode-division multiplexing In this paper, three general architectures for on-chip optical space and mode switching are proposed, which are optimized for optical space switching, optical space switching plus local optical mode switching, and global optical mode switching, respectively A silicon thermo-optic 2×2 four-mode optical switch is demonstrated The minimum and maximum optical link insertion losses are 160 and 209 dB (including ∼6 dB coupling loss), respectively, in the wavelength range of 1525–1565 nm, while the optical signal-to-noise ratios of the optical links are larger than 153 dB The optical power penalty at a bit error rate of 10−9 varies from 10 to 56 dB for 40 Gbps data transmission through different optical links This work provides a systematic solution to on-chip information switching for different physical and mode channels

An Ultrabroadband Mid-Infrared Pulsed Optical Switch Employing Solution-Processed Bismuth Oxyselenide.

Abstract: Pulsed lasers operating in the mid-infrared (3-25 µm) are increasingly becoming the light source of choice for a wide range of industrial and scientific applications such as spectroscopy, biomedical research, sensing, imaging, and communication. Up to now, one of the factors limiting the mid-infrared pulsed lasers is the lack of optical switch with a capability of pulse generation, especially for those with wideband response. Here, a semiconductor material of bismuth oxyselenide (Bi2 O2 Se) with a facile processibility, constituting an ultrabroadband saturable absorber for the mid-infrared (actually from the near-infrared to mid-infrared: 0.8-5.0 µm) is exhibited. Significantly, it is found that the optical response is associated with a strong nonlinear character, showing picosecond response time and response amplitude up to ≈330.1% at 5.0 µm. Combined with facile processibility and low cost, these solution-processed Bi2 O2 Se materials may offer a scalable and printable mid-infrared optical switch to open up the long-sought parameter space which is crucial for the exploitation of compact and high-performance mid-infrared pulsed laser sources.

Hybrid Silicon Photonic-Lithium Niobate Electro-Optic Mach-Zehnder Modulator Beyond 100 GHz

Abstract: Electro-optic modulation, the imprinting of a radio-frequency (RF) waveform on an optical carrier, is one of the most important photonics functions, being crucial for high-bandwidth signal generation, optical switching, waveform shaping, data communications, ultrafast measurements, sampling, timing and ranging, and RF photonics. Although silicon (Si) photonic electro-optic modulators (EOMs) can be fabricated using wafer-scale technology compatible with the semiconductor industry, such devices do not exceed an electrical 3-dB bandwidth of about 50 GHz, whereas many applications require higher RF frequencies. Bulk Lithium Niobate (LN) and etched LN modulators can scale to higher bandwidths, but are not integrated with the Si photonics fabrication process adopted widely over the last decade. As an alternative, an ultra-high-bandwidth Mach-Zehnder EOM based on Si photonics is shown, made using conventional lithography and wafer-scale fabrication, bonded to an unpatterned LN thin film. This hybrid LN-Si MZM achieves beyond 100 GHz 3-dB electrical bandwidth. Our design integrates silicon photonics light input/output and optical components, including directional couplers, low-radius bends, and path-length difference segments, realized in a foundry Si photonics process. The use of a simple low-temperature (200C) back-end integration process to bond a postage-stamp-sized piece of LN where desired, and achieving light routing into and out of LN to harness its electro-optic property without any etching or patterning of the LN film, may be broadly-useful strategies for advanced integrated opto-electronic microchips.

A Survey of Optical Carrier Generation Techniques for Terabit Capacity Elastic Optical Networks

Abstract: Elastic optical networks (EON) have been proposed to meet the network capacity and dynamicity challenges. Hardware and software resource optimization and re-configurability are key enablers for EONs. Recently, innovative multi-carrier transmission techniques have been extensively investigated to realize high capacity (Tb/s) flexible transceivers. In addition to standard telecommunication lasers, optical carrier generators based on optical frequency combs (OFC) have also been considered with expectations of reduced cost and inventory, improved spectral efficiency, and flexibility. A wide range of OFC generation techniques have been proposed in the literature over the past few years. It is imperative to summarize the state of the art, compare and assess these diverse techniques from a practical perspective. In this survey, we identify salient features of optical multicarrier generators, review and compare these techniques both from a physical and network layer perspective. OFC demultiplexing/filtering techniques have also been reviewed. In addition to transmission performance, the impact of such sources on the network performance and real-world deployment strategies with reference to cost, power consumption, and level of flexibility have also been discussed. Field trials, integrated solutions, and flexibility demonstrations are also reported. Finally, open issues and possible future directions that can lead to real network deployment are highlighted.

Tutorial: Integrated-photonic switching structures

Abstract: Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms Practical actuation of switches by electro-optical and thermo-optical techniques is discussed Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks Potential is found in the reconfigurable, programmable “mesh” switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers Many important matrix switches use gated semiconductor optical amplifiers The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators The res

All optical switching and associated technologies: a review

Abstract: Optical computation is the most desirable technology that enhances the speed, data transmission rate and processing power by replacing the electronics with the optical switches. Optical switching is efficiently performed in high speed signal processing by all optical gates. This paper reviews the progressive development of the optical switching technology, highlights the different technologies of all optical gates and other switching circuits in all optical processing. Basic gates and other logic circuits in optical computing based on nonlinear regimes using semiconductor optical amplifier (SOA), fiber and photonic crystals are discussed, compared and the challenges along with future direction is outlined.

Realization and Application of Large-Scale Fast Optical Circuit Switch for Data Center Networking

Abstract: Applying optical switching to data center networks can greatly expand network bandwidth and reduce electrical power consumption, both of which are needed to meet the explosive traffic increase. The optical switch offers large bandwidth switching capability, and so eliminates the multistage switch network architecture needed with electrical switching. Furthermore, the single stage architecture of the optical switch greatly simplifies operating costs, which include cabling, while substantially reducing the number of transponders needed. Data center networks place very different demands on optical systems than communication networks. Grasping the right direction to proceed is of paramount importance. To realize the full potential of optical switches, such as scalability and cost effectiveness, we analyze the role of large-scale optical circuit switches and discuss the realization technologies that combine the two dimensions of space and wavelength. Our recent advances in large port-count optical switches are presented.

Low-loss and broadband non-volatile phase-change directional coupler switches

Abstract: An optical equivalent of the field-programmable gate array (FPGA) is of great interest to large-scale photonic integrated circuits. Previous programmable photonic devices relying on the weak, volatile thermo-optic or electro-optic effect usually suffer from a large footprint and high energy consumption. Phase change materials (PCMs) offer a promising solution due to the large non-volatile change in the refractive index upon phase transition. However, the large optical loss in PCMs poses a serious problem. Here, by exploiting an asymmetric directional coupler design, we demonstrate PCM-clad silicon photonic 1 \times 2 and 2 \times 2 switches with a low insertion loss of ~1 dB and a compact coupling length of ~30 {\mu}m while maintaining a small crosstalk less than ~10 dB over a bandwidth of 30 nm. The reported optical switches will function as the building blocks of the meshes in the optical FPGAs for applications such as optical interconnects, neuromorphic computing, quantum computing, and microwave photonics.

Hybrid Photonic-Plasmonic Nonblocking Broadband 5 × 5 Router for Optical Networks

Abstract: Photonic data routing in optical networks is expected to overcome the limitations of electronic routers with respect to data rate, latency, and energy consumption. However, photonics-based routers suffer from dynamic power consumption, and nonsimultaneous usage of multiple wavelength channels when microrings are deployed and are sizable in footprint. Here, we show a design for the first hybrid photonic-plasmonic, nonblocking, broadband $5\times 5$ router based on 3-waveguide silicon photonic-plasmonic $2\times 2$ switches. The compactness of the router (footprint $ ) results in a short optical propagation delay (0.4 ps) enabling high data capacity up to 2 Tb/s. The router has an average energy consumption ranging from 0.1 to 1.0 fJ/bit depending on either DWDM or CDWM operation, enabled by the low electrical capacitance of the switch. The total average routing insertion loss of 2.5 dB is supported via an optical mode hybridization deployed inside the $2\times 2$ switches, which minimizes the coupling losses between the photonic and plasmonic sections of the router. The router's spectral bandwidth resides in the S, C, and L bands and exceeds 100 nm supporting wavelength division multiplexing applications since no resonance feature is required. Taken together this novel optical router combines multiple design features, all required in next-generation high data-throughput optical networks and computing systems.

Silicon Photonic Switch Subsystem With 900 Monolithically Integrated Calibration Photodiodes and 64-Fiber Package

Abstract: A packaged and fully operational 32 × 32 silicon photonic switch chip having 448 switch cells and 1856 crossings is demonstrated. The switch chip includes 900 monolithically integrated photodiodes used for calibrating the thermo-optic Mach–Zehnder switch cells. The calibration procedure employs an external laser source and follows a reachability-tree sequence to calibrate all switch cells. The accuracy of the calibration is demonstrated by the measurement of switch cell extinction ratios, for both states of each switch cell. The mean extinction ratio for both states is 35 dB. Arbitrary light path switching is demonstrated. Measurement of the channel-to-channel crosstalk was performed for a large number of aggressor and victim light path combinations. The matrix crosstalk is dominated by contributions from waveguide crossings. The die was wire-bonded to a custom ceramic package, to which a 68-fiber ribbon was permanently attached, which coupled the input and output optical signals to edge couplers on the chip through a waveguide pitch- and mode-concentrating silica chip. The fiber-to-fiber loss of on-chip loopback waveguides was less than 6.5 dB from 1530 to 1565 nm. The entirety of switch cells and monitors was driven by controller boards and A/D chips using a controller field-programmable gate array (FPGA). The calibration procedure was completed in less than 10 min using only the on-chip monitors, without off-chip detectors. The chip was recalibrated after six months storage, and the measured change in drive current was within the calibration uncertainty, indicating that the chip and driver are stable over time.

Advanced Passive Silicon Photonic Devices With Asymmetric Waveguide Structures

Abstract: Various passive photonic integrated devices have been developed successfully with silicon-on-insulator (SOI) nanowires in the past decade. It is well known that SOI-nanowire waveguides have ultrahigh index contrast ( $\Delta $ ) and ultrahigh birefringence. As a result, the structures and the design rules of a silicon photonic device are probably very different from the conventional case of using low- $\Delta $ optical waveguides. For example, some asymmetric waveguide structures have been used often to realize many silicon photonic devices developed recently. Furthermore, higher order modes have been involved in some of these silicon photonic devices. This paper discusses the special mode properties of silicon nanophotonic waveguides, including birefringence, mode dispersion, and mode hybridness. A review is then given on recent progress of these advanced passive silicon photonic devices with structural asymmetry, including on-chip polarization-handling devices, mode converters/(de)multiplexers, microring-resonator optical filters/switches, and Mach..Zehnder interferometer optical switches. Silicon photonic integrated circuits with these building blocks are also reviewed, including hybrid (de)multiplexers and reconfigurable optical add..drop multiplexers.

Loss-induced transparency in optomechanics.

Abstract: We study optomechanically induced transparency (OMIT) in a compound system consisting of coupled optical resonators and a mechanical mode, focusing on the unconventional role of loss. We find that optical transparency can emerge at the otherwise strongly absorptive regime in the OMIT spectrum, by using an external nanotip to enhance the optical loss. In particular, loss-induced revival of optical transparency and the associated slow-to-fast light switch can be identified in the vicinity of an exceptional point. These results open up a counterintuitive way to engineer micro-mechanical devices with tunable losses for e.g., coherent optical switch and communications.

16 × 16 Silicon Optical Switch Based on Dual-Ring-Assisted Mach–Zehnder Interferometers

Abstract: In this paper, we report a nanosecond 16 × 16 silicon electro-optic switch chip based on a Benes architecture. The switch adopts dual-ring-assisted Mach–Zehnder interferometers as the basic building blocks. In each switch element, both TiN microheaters and PIN diodes are integrated for ring resonance alignment and high-speed switching, respectively. A transfer-matrix-based theoretical model is established to analyze the switch performances. The 16 × 16 switch is characterized by measuring the optical transmission spectra and quadrature phase-shift keying (QPSK) data transmission through 16 representative optical paths. The insertion loss of the entire switch chip is 10.6 ± 1.7 dB and the crosstalk is less than −20.5 dB. The 32-Gb/s QPSK signal is successfully switched to different destination ports by reconfiguring the optical paths, verifying the signal integrity after switching.

Waveguide magneto-optical devices for photonics integrated circuits [Invited]

Abstract: In a planar waveguide including magneto-optical (MO) material with in-plane magnetization, a MO phase shift due to a first-order MO effect is induced. A Mach-Zehnder interferometer (MZI)-based optical isolator and circulator are fabricated by the direct bonding technique between silicon and MO garnets. The MZI can provide optical switching by dynamic control of the magnetization and latching operation with nonvolatile magnetic film. In this paper, waveguide-type MO isolator and switch for photonic integrated circuits are presented.

High-port low-latency optical switch architecture with optical feed-forward buffering for 256-node disaggregated data centers.

Abstract: Departing from traditional server-centric data center architectures towards disaggregated systems that can offer increased resource utilization at reduced cost and energy envelopes, the use of high-port switching with highly stringent latency and bandwidth requirements becomes a necessity. We present an optical switch architecture exploiting a hybrid broadcast-and-select/wavelength routing scheme with small-scale optical feedforward buffering. The architecture is experimentally demonstrated at 10Gb/s, reporting error-free performance with a power penalty of <2.5dB. Moreover, network simulations for a 256-node system, revealed low-latency values of only 605nsec, at throughput values reaching 80% when employing 2-packet-size optical buffers, while multi-rack network performance was also investigated.

Thermal tuning capabilities of semiconductor metasurface resonators

Abstract: Metasurfaces exploit the ability to engineer the optical phase, amplitude and polarization at subwavelength dimensions providing unprecedented control of light. The realization of the all dielectric approach to metasurfaces has led to the demonstration of extensive flat optical elements and functionalities with low losses. However, to reach their ultimate potential, metasurfaces must move beyond static operation and incorporate active tunability and reconfigurable functions. The central challenge is achieving large tunability in subwavelength resonator elements which require large optical effects in response to external stimuli. Here we study the thermal tunability of high-index silicon and germanium semiconductor resonators over a large temperature range. We demonstrate thermal tuning of Mie resonances due to the normal positive thermo-optic effect (dn/dT >0) over a wide infrared range. We show that at higher temperatures and long wavelengths the sign of the thermo-optic coefficient is reversed (dn/dT<0) culminating in a negative induced index due to thermal excitation of free carriers. We also demonstrate the tuning of high order Mie resonances by several linewidths with a temperature swing of {\Delta}T<100K. Finally, we exploit the larger thermo-optic coefficient at NIR wavelengths in Si metasurfaces to realize optical switching and tunable metafilters.

Asymmetric photon transport in organic semiconductor nanowires through electrically controlled exciton diffusion

Abstract: The ability to steer the flow of light toward desired propagation directions is critically important for the realization of key functionalities in optical communication and information processing. Although various schemes have been proposed for this purpose, the lack of capability to incorporate an external electric field to effectively tune the light propagation has severely limited the on-chip integration of photonics and electronics. Because of the noninteractive nature of photons, it is only possible to electrically control the flow of light by modifying the refractive index of materials through the electro-optic effect. However, the weak optical effects need to be strongly amplified for practical applications in high-density photonic integrations. We show a new strategy that takes advantage of the strong exciton-photon coupling in active waveguides to effectively manipulate photon transport by controlling the interaction between excitons and the external electric field. Single-crystal organic semiconductor nanowires were used to generate highly stable Frenkel exciton polaritons with strong binding and diffusion abilities. By making use of directional exciton diffusion in an external electric field, we have realized an electrically driven asymmetric photon transport and thus directional light propagation in a single nanowire. With this new concept, we constructed a dual-output single wire–based device to build an electrically controlled single-pole double-throw optical switch with fast temporal response and high switching frequency. Our findings may lead to the innovation of concepts and device architectures for optical information processing.

A Photonic Switch Based on a Hybrid Combination of Metallic Nanoholes and Phase-change Vanadium Dioxide.

Abstract: A photonic switch is an integral part of optical telecommunication systems. A plasmonic bandpass filter integrated with materials exhibiting phase transition can be used as a thermally reconfigurable optical switch. This paper presents the design and demonstration of a broadband photonic switch based on an aluminium nanohole array on quartz utilising the semiconductor-to-metal phase transition of vanadium dioxide. The fabricated switch shows an operating range over 650 nm around the optical communication C, L, and U band with maximum 20%, 23% and 26% transmission difference in switching in the C band, L band, and U band, respectively. The extinction ratio is around 5 dB in the entire operation range. This architecture is a precursor for developing micron-size photonic switches and ultra-compact modulators for thin film photonics.

Two-dimensional beam-steering device using a doubly periodic Si photonic-crystal waveguide.

Abstract: We demonstrate a nonmechanical, on-chip optical beam-steering device using a photonic-crystal waveguide with a doubly periodic structure that repeats the increase and decrease of the hole diameter. We fabricated the device using a complementary metal–oxide–semiconductor process. We obtained a beam-deflection angle of 24° in the longitudinal direction, while maintaining a divergence angle of 0.3°. Four such waveguides were integrated, and one was selected by a Mach–Zehnder optical switch. We obtained lateral beam steering by placing a cylindrical lens above these waveguides. By combining the lateral and longitudinal beam steering, we were able to scan the collimated beam in two dimensions, with 80 × 4 resolution points.

Deep-neural-network-based wavelength selection and switching in ROADM systems

Abstract: Recent advances in software and hardware greatly improve the multi-layer control and management of reconfigurable optical add-drop multiplexer (ROADM) systems facilitating wavelength switching. However, ensuring stable performance and reliable quality of transmission (QoT) remain difficult problems for dynamic operation. Optical power dynamics that arise from a variety of physical effects in the amplifiers and transmission fiber complicate the control and performance predictions in these systems.We present a deep-neural-network-based machine learning method to predict the power dynamics of a 90-channel ROADM system from data collection and training. We further show that the trained deep neural network can recommend wavelength assignments for wavelength switching with minimal power excursions.