Filterless optical networks use passive splitters and combiners with coherent optics, providing wavelength selection in the digital domain, while forming a passive fiber-tree topology between nodes. In this study, we investigate the optimal design of filterless optical networks while minimizing the number of required wavelengths. We propose a Dantzig–Wolfe decomposition model in which each subproblem

The dynamic bandwidth allocation (DBA) algorithm is highly impactful in improving the network performance of gigabit passive optical networks (GPON). However, reports delineating its vulnerability to certain attacks can be found in the literature, thus raising concerns. A degradation attack manipulates the transmission control protocol (TCP) congestion control algorithm, which may impact the received

Applications of machine learning (ML) models in optical communications and networks have been extensively investigated. For an optical wavelength-division-multiplexing (WDM) system, the quality of transmission (QoT) estimation generally depends on many parameters including the number and arrangement of WDM channels; launch power of each channel; number and distribution of fiber spans; attenuation,

Access links that connect cloud data centers or enterprise networks to public networks are important parts of the network infrastructure and make up considerable portions of overall network expenditures. When a customer network is connected to an overlaid elastic optical network, determining the capacity of the access link is difficult. Furthermore, access links carry mixed packet streams and circuit

With the fast deployment of datacenters (DCs), bandwidth-intensive multicast services are becoming more and more popular in metro and wide-area networks, to support dynamic applications such as DC synchronization and backup. Hence, this work studies the problem of how to formulate and reconfigure multicast sessions in an elastic optical network (EON) dynamically. We propose a deep reinforcement learning

The feasibility of a time-domain technique, proposed for uplink synchronization of the bandwidth scalable orthogonal frequency division multiple access passive optical network (BS-OFDMA PON), is experimentally demonstrated. The results show that a delay variation of less than 50% of the cyclic prefix is tolerable, relaxing the thin time synchronization required in the uplink of the evaluated architecture

Passive optical networks (PONs) are widely deployed worldwide as access networks, and various standards have been created to serve the demands of different markets. In recent years, software-defined-network-enabled broadband access (SEBA) has been studied for the realization of flexible and cost-effective PONs, while the zero touch provisioning (ZTP) function of optical line terminals (OLTs) and optical

We propose an ultradense wavelength-division-multiplexing (WDM) network architecture that dramatically enhances channel accommodation density to achieve extremely high spectral efficiency. The trade-offs between high spectral efficiency and severe signal impairment due to optical filtering are resolved by network optimization of the overlaid subnetworks based on fiber-granular routing and wavelength-granular

Ultra-high-capacity indoor wireless connectivity is considered a key technology enabler to support end-to-end delivery of new services in the beyond-5G and 6G era. With physical layer data rates well beyond 10 Gbps, optical wireless communication (OWC) technology is positioning itself as a prospective candidate to support these services. While OWC is capable of handling multi-gigabit data rates in

We present a prototype transponder with fast synchronized change of parameters in the case of traffic quality degradation thanks to link impairment detection and autonegotiation capabilities. This concept has been implemented and validated in real time using a field programmable gate array (FPGA) platform, a Raspberry Pi, and a commercial transponder. We introduce an autonegotiation protocol for local

Next-generation Ethernet passive optical networks (NG-EPONs) were standardized by the IEEE 802.3 Working Group in 2020 [IEEE 802.3ca-2020–IEEE Standard for Ethernet Amendment 9: physical layer specifications and management parameters for 25 Gb/s and 50 Gb/s passive optical networks, 2020]. Due to the channel bonding technology [“Recent progress on 25G EPON and beyond,” in 42nd European Conference on

Mobility management is an important part of the analysis and design of ultra-dense LiFi networks. This paper thus presents a two-tier LiFi network and analyses the cross-tier handover rate between the primary and secondary cells. For different conditions of semiangle at half illuminance of the primary and secondary cells, we propose three different coverage models for the secondary cells. Using stochastic

Network infrastructure must support emerging applications, fulfill 5G requirements, and respond to the sudden increase of societal need for remote communications. Remarkably, crowdsourced live video streaming (CLVS) challenges operators’ infrastructure with tides of users attending major sport or public events that demand high bandwidth and low latency jointly with computing capabilities at the networks’

The key goal in optical network design is to introduce intelligence in the network and deliver capacity when and where it is needed. It is critical to understand the dependencies between network topology properties and the achievable network throughput. Real topology data of optical networks are scarce, and often large sets of synthetic graphs are used to evaluate their performance including proposed

Point to point (PtP), wavelength division multiplexing (WDM) and time division multiplexing (TDM) optical interfaces are discussed as solutions for backhaul, midhaul, and fronthaul networks. The evolution of radio access networks (RANs) for 5G and beyond is introduced and PtP is identified as the most deployed solution, with many transceiver technologies available to cover the different needs for each

With the rapid spread of cloud-based services, intra-datacenter traffic is growing exponentially. In typical present datacenters, top-of-rack switches, which act as gateways to computer systems, are interconnected via multi-tier electrical-switching networks. The electrical switch necessitates costly optical-to-electrical and electrical-to-optical conversion. Furthermore, its power consumption will

The surge in Internet usage and connectivity worldwide coupled with the emergence of 5G mobile communications has amplified the need for a scalable and sustainable telco networking model. This paper outlines our Open Broadband trial in Brazil and the journey to open software and whitebox hardware as a practical approach to scaling fiber access networks enabling integration into a software-defined network

With 50G passive optical networks (PONs) currently being standardized, we review the challenges of meeting the high loss budgets required in such high speed fiber access networks. Simulations of the 50 Gb/s link performance show the impact of critical parameters when using 25G-class avalanche photodiode receivers with digital signal processing. We describe how a 1342 nm electro-absorption modulated

This paper presents an experimental evaluation of network protocols for control and management of optical networks and optical network equipment as seen in current trends. This paper presents the YANG data modeling language and its associated RESTCONF/NETCONF protocols. Later, it details multiple data models used in optical networks, such as IETF TEAS, ONF Transport API, OpenROADM, and OpenConfig.

The potential to operate third-party terminals over multi-domain transparent optical networks attracts operators and customers to implement optical spectrum as a service (OSaaS). Because infrastructure information cannot always be shared with OSaaS end customers, alternatives to off-line quality of transmission (QoT) estimation tools are required to assess the performance of the spectrum slot to estimate

In recent years, optical networks have become more complex due to traffic increase and service diversification, and it has become increasingly difficult for network operators to monitor large-scale networks and keep track of communication status at all times, as well as to control and operate the various services running on the networks. This issue is motivating the need for autonomous optical network

Recent advances in physical layer optics have made slicing of optical bands into multiple subbands with different bandwidths possible. Due to this development, spectrum allocation has become easier in elastic optical networks (EONs). More specifically, owing to the slicing technology, the defragmentation problem in EONs can be addressed easily, i.e., more demands can be fit into empty spectrum slots

Having ubiquitous optical monitors in dense wavelength-division multiplexing (DWDM) or flex-grid networks allows the estimation in real time of crucial parameters. Such monitoring would be even more important in disaggregated optical networks, to inspect performance issues related to inter-vendor interoperability. Several important parameters can be retrieved using optical spectrum analyzers (OSAs)

Spatial-division multiplexing (SDM) and band-division multiplexing (BDM) have emerged as solutions to expand the capacity of existing C-band wavelength-division multiplexing (WDM) optical systems and to deal with increasing traffic demands. An important difference between these two approaches is that BDM solutions enable data transmission over unused spectral bands of already-deployed optical fibers

A combined non-orthogonal multiple access (NOMA) and multiband carrierless amplitude and phase modulation (multiCAP) scheme is proposed for flexible resource provisioning in coherent passive optical networks (PONs). While the proposed combination increases the data-rate and the number of users through the inclusion of NOMA and multiCAP, the coherent reception increases the range and splitting factor

Optical interconnection networks promise to overcome the limitations of current electronic switching fabrics, enabling higher throughput, lower latency, and lower power consumption. Multi-plane architectures, based on multiple optical switching domains (e.g., space, time, wavelength, orbital angular momentum), are gaining research attention because of their modularity and scalability compared to single-domain

We propose autonomous dynamic window shaping and rerouting to improve the throughput of the Internet of Things (IoT) on a service-converged layer-2 network with a time-aware shaper (TAS) accommodating mobile fronthaul (MFH) and IoT backhaul. While low latency for MFH is assured by the TAS technique, the maximum throughput of the IoT traffic is limited because the available bandwidth for the IoT is

Maintaining high-performance operation under dynamic and nonuniform network traffic has been a technical challenge in current data center networks (DCNs). With the aim to provide better quality of service (QoS) for diverse applications, this work presents a dynamic and adaptive DCN reconfiguration framework based on deep reinforcement learning (DCR2L). The proposed framework is integrated into the

Long short-term memory neural networks demonstrate a classification accuracy larger than 99% for highly variable and bursty, real-time server traffic flows. Their performance in terms of forecasting precision displays promising results, both for one-step as well as multi-step predictions. These capabilities make the a priori detection of heavy data streams possible, thus enabling the employment of

High deployment cost with respect to expected revenue is the main barrier to fiber-to-the-home (FTTH) roll-out in rural areas. This problem, as shown in this paper, is exacerbated by the uncertainty associated with the end-user take-up rate. The randomness associated with subscribers’ service take-up yields considerable fluctuation and escalation in the total cost of deployment. This adverse and varying

By associating machine learning and an analytical model (i.e., the Gaussian noise model), we reduce uncertainties on the output power profile and the noise figure of each amplifier in an optical network. We leverage the signal-to-noise ratio (SNR) of all the light paths of an optical network, monitored in all the coherent receivers. The learning process is based on a gradient-descent algorithm where

This paper proposes, designs, and validates a filterless metro network employing bidirectional transmission over a single fiber. Transmission impairments, dominated by cross talk, are specifically estimated leveraging on what we believe to be novel closed-form expressions to determine optical reach, launch power, and number of supported cascaded nodes. Results show that extremely good transmission

This paper proposes a machine-learning (ML)-aided cognitive approach for effective bandwidth reconfiguration in optically interconnected datacenter/high-performance computing (HPC) systems. The proposed approach relies on a Hyper-X-like architecture augmented with flexible-bandwidth photonic interconnections at large scales using a hierarchical intra/inter-POD photonic switching layout. We first formulate

We propose a fast and accurate signal quality monitoring scheme that uses convolutional neural networks for error vector magnitude (EVM) estimation in coherent optical communications. We build a regression model to extract EVM information from complex signal constellation diagrams using a small number of received symbols. For the additive-white-Gaussian-noise-impaired channel, the proposed EVM estimation

This paper proposes an evolutionary transfer learning approach (Evol-TL) for scalable quality-of-transmission (QoT) estimation in multi-domain elastic optical networks (MD-EONs). Evol-TL exploits a broker-based MD-EON architecture that enables cooperative learning between the broker plane (end-to-end) and domain-level (local) machine learning functions while securing the autonomy of each domain. We

Flexible grid networks need rigorous resource planning to avoid network over-dimensioning and resource over-provisioning. The network must provision the hardware and spectrum resources statically, even for dynamic random bandwidth demands, due to the infrastructure of flexible grid networks, hardware limitations, and reconfiguration speed of the control plane. We propose a flexible online–offline probabilistic

Availability is a key service metric when deploying service function chains (SFCs) over network slices in 5G networks. We study the problem of determining the composition of a slice for a service function chain and the mapping of the slice to the physical transport network in a way that guarantees availability of the SFC while minimizing cost. To improve the availability, we design a slice that provides

With the stringent requirements of fifth-generation and beyond wireless communications technology coupled with the potential bottleneck in the optical fronthaul, radio-over-fiber (RoF) technology offers an alternative solution to distribute the wireless signals while meeting these requirements. The inherent centralized architecture of RoF enables advanced coordination functionality to be performed

As the communication infrastructure that sustains critical societal services, optical networks need to function in a secure and agile way. Thus, cognitive and automated security management functionalities are needed, fueled by the proliferating machine learning (ML) techniques and compatible with common network control entities and procedures. Automated management of optical network security requires

Reliable and conservative computation of the quality of transmission (QoT) of transparent lightpaths (LPs) is a crucial need for software-defined control and management of the wavelength division multiplexing optical transport. The LP QoT is summarized by the generalized SNR (GSNR) that can be computed by a QoT estimator (QoT-E). Within the context of network automation, the QoT-E must rely only on

This paper proposes and demonstrates a hybrid-learning-assisted impairments abstraction framework for planning and provisioning intra- and inter-domain services in a field-trial multi-domain optical network testbed. The proposed abstraction strategy consists of a parametric and a non-parametric machine learning technique to allow the control plane to implement impairments abstraction with different

Optical wireless access networks have seen rapid progress. With beam-steering capability, optical wireless communications can deliver very high capacity, support user mobility with indoor localization supported directly at the optical layer, be resilient against the blocking of beams by exploiting spatial diversity at the optical layer, and guarantee low-latency links with modified protocols and network

To deal with the challenging requirements of metropolitan area networks (MANs), it is essential to design cost-effective systems that can support high capacity and dynamic adaptation, as well as a synergy of programmability and efficient photonic technologies. This becomes crucial for very large MANs that support 5G, where multihop connections will need to be dynamically established at target capacities

The fifth generation (5G) mobile communications system is envisioned to serve various mission-critical services such as industrial automation, cloud robotics, and safety-critical vehicular communications. To satisfy the stringent end-to-end latency requirement of these services, fog computing has been regarded as a promising technology to be integrated into 5G networks, in which computing, storage

The future-generation passive optical network (PON) physical layer, targeting 100 Gbps/wavelength, will have to deal with severe optoelectronics bandwidth and chromatic dispersion limitations. In this paper, largely extending our Optical Fiber Communication Conference (OFC) 2020 invited paper, we review 100 Gbps/wavelength PON downstream alternatives over standard single-mode fiber in the O- and C-bands

Toward the forthcoming spatial division multiplexing (SDM) era, a spatial channel network (SCN) was recently proposed in which the optical layer is explicitly decoupled from the hierarchical SDM and wavelength division multiplexing (WDM) layers, and an optical node evolves into a spatial cross-connect (SXC) and wavelength cross-connect (WXC) to achieve a hierarchical optical cross-connect (HOXC). In

Coherent optics has been proved to be a promising candidate for 100 Gb/s and even beyond single-wavelength time-division multiplexing passive optical networks (TDM-PONs). However, one of the key issues in TDM coherent-PON is how to efficiently and robustly achieve upstream burst-mode coherent detection. To solve this problem, we proposed and demonstrated a reliable and efficient preamble design with

SDN Enabled Broadband Access (SEBA) is a large open-source development and integration project hosted by the Open Networking Foundation (ONF). Built using white-box hardware, merchant silicon, and SDN principles, SEBA brings the benefits of virtualization and cloudification to passive optical network (PON)-based broadband access networks for FTTH/FTTB deployments. Already in field trials with several

Channel measurements for a 50G passive optical network (PON) show a significant amount of intersymbol interference (ISI) due to chromatic dispersion (CD) and the use of low-cost, bandwidth-limited 25 Gbaud class components. The channel characteristics at the input of the forward error correction (FEC) decoder are measured for several receiver equalization schemes, and the error correlation at the output

We investigate the advantages of using co-packaged optics for building low-diameter, large-scale high-performance computing (HPC) and data center networks. The increased escape bandwidth offered by co-packaged optics can enable high-radix switch implementations of more than 150 switch ports, which can be combined with data rates of up to 400 Gb/s per port. From the network architecture perspective

In this paper, we identify challenges in developing future optical network infrastructure for new services based on technologies such as 5G, virtual reality, and artificial intelligence, and we suggest approaches to handling these challenges that include a business model, architecture, and diversity. Through activities in multiservice agreement and de facto standard organizations, we have shown how

Machine learning (ML) is currently being investigated as an emerging technique to automate quality of transmission (QoT) estimation during lightpath deployment procedures in optical networks. Even though the potential network-resource savings enabled by ML-based QoT estimation has been confirmed in several studies, some practical limitations hinder its adoption in operational network deployments. Among

This paper provides an overview of transceiver technologies to be used for current and next-generation passive optical networks (PONs). The uninterrupted scaling of PONs to higher bitrates in a cost-effective way to meet future bandwidth demands will drive the need for continuous improvement in PON transceiver technologies. In this paper we try to analyze the requirements needed and the impact on this

Network operators are facing a critical issue on their optical transport networks to deploy 5G$+$+ and Internet of Things services. They need to address the capacity increase by a factor of 10, while keeping a similar cost per user. Over the past years, network operators have been working on the optical disaggregated approach with great interest for achieving the required efficiency and cost reduction

Machine learning (ML) is increasingly applied in optical network management, especially in cross-layer frameworks where physical layer characteristics may trigger changes at the network layer due to transmission performance measurements (quality of transmission, QoT) monitored by optical equipment. Leveraging ML-based QoT estimation approaches has proven to be a promising alternative to exploiting

The dis-aggregated passive optical network (PON) optical line terminal (OLT) architecture is attracting attention in academia and industry. This paper first reviews the evolution in dynamic bandwidth allocation (DBA) dis-aggregation. We further enhance the scalability of the dis-aggregated PON-OLT by reducing the bandwidth overhead of REPORT/GATE, the time division multiplexing (TDM) control information

The introduction of 5G, the increasing number of connected devices, and the exponential growth of services relying on connectivity are pressuring multilayer networks to improve their scaling, efficiency, and controlling capabilities. However, enhancing those features consistently results in a significant amount of complexity in operating the resources available across heterogeneous vendors and technology

We propose a single-stage network architecture for intra-node connectivity that makes use of nanosecond-scale photonic switches. Although buffering at the switch points is of vital importance for complex multistage networks, this is not the case for smaller-scale single-stage networks where the end nodes are located only one hop apart. By limiting the buffering to the end points, the proposed architecture

To support newly emerging and highly dynamic 5G services, optical metro networks must be capable of provisioning services on the fly. Network function virtualization (NFV) is leveraged to fulfill these dynamic service demands by placing virtual network functions (VNFs) in NFV-capable network nodes and chaining them together (“service chaining”). In addition, new 5G service chains often have bandwidth

In space-division multiplexing elastic optical networks (SDM-EONs) based on multicore fibers, the problem of finding a lightpath for a new connection request involves routing, modulation, spectrum, and core assignment (RMSCA). A lightpath can be constructed using contiguous free frequency slot (FS) blocks with different frequency slot allocation patterns (FSAPs), where each FSAP can incur different