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

An online parameter-tuning method for the energy-efficient data center network (DCN) named HOLST (high-speed optical layer 1 switch system for time-slot-switching-based optical data center networks) is proposed. HOLST comprises an optical circuit switching network, optical slot switching network, and electrical packet switching network for the spine layer. It requires flows to be assigned to optimal

This paper provides a performance analysis of a simultaneous free-space-optics (FSO) and millimeter wave (mmWave) communication system with selection-combining and maximal-ratio-combining receivers over the ${\cal F}$F-distribution channel. The ${\cal F}$F-distribution model can be used to represent both the mmWave and FSO channels with proper selection of parameters. In particular, an exact-form analysis

The dynamicity of today’s optical networks is far from its potential. Optical components, such as fast-tunable lasers or semiconductor optical amplifiers, can react on a nanosecond time scale, while the reconfiguration time of optical networks is many orders of magnitude larger, normally above a hundreds of milliseconds timescale. In this work, we address this gap with real-time control plane strategies

Network connectivity, i.e., the reachability of any network node from all other nodes, is often considered as the default network survivability metric against failures. However, in the case of a large-scale disaster disconnecting multiple network components, network connectivity may not be achievable. On the other hand, with the shifting service paradigm towards the cloud in today’s networks, most

In this paper, we study the quality of transmission (QoT) aware routing, modulation level, and resource assignment problem for transparent flexible optical networks over few-mode multi-core fibers. We consider two three-dimensional resource assignment (3DRA) algorithms, called liberal and conservative, that are compatible with fractional joint switching. The three resource dimensions are core, mode

With a focus on service interruptions occurring in optical networks, we propose a failure prognostics scheme based on a bi-directional gated recurrent unit (BiGRU) from the perspective of time-series processing, which leverages actual datasets from the network operator. BiGRU neural networks can capture the temporal features of multi-sourced data and incorporate contextual information. A principal

Industry 4.0 represents a new industrial revolution that will dramatically change the landscape in many sectors, including manufacturing and logistics. Robotics, machine intelligence, and new forms of connectivity are key ingredients of this paradigm. 5G mobile networks are expected to play a crucial role, supporting a lower cost per transported bit in air and a lower latency compared with 4G. 5G radio

To cope with the dynamic datacenter (DC) traffic matrix generated by multiple applications, load balancing algorithms can be deployed to improve the datacenter network (DCN) performance. OPSquare, as a promising optical DCN architecture, adopts fast optical switches to provide high bandwidth, low latency, large scalability, and cost and energy efficiency. Current load balancing algorithms are not optimal

Aiming to solve the low utilization and high operational cost in current data centers and the diversified resource requirements for different application types, we propose and investigate what we believe to be a novel rack-scale disaggregated optical data center network (RDON). Different types of hardware resources (i.e., CPU, memory, and storage) are deployed in standalone resource pools of the RDON

Hybrid light fidelity (LiFi) and wireless fidelity (WiFi) networks provide a promising solution for future indoor wireless communication. Hybrid networks face the challenge of imbalanced cell load due to the uneven distribution of user equipment (UE), and they need to suppress inter-cell interference induced by the dense deployment of LiFi access points (APs). In this paper, with the aim to efficiently

Fixed optical transport is the predominant fronthaul technology for 4G mobile access networks, carrying the traffic between the central office and subtended antenna sites. With the new functional splits and related standards introduced in 5G, new capacity and quality-of-service requirements are imposed on optical transport. In this paper, we discuss low-cost high-capacity optical fronthaul solutions

We present a fixed mobile convergence topology for analog intermediate frequency over fiber (A-IFoF)/millimeter-wave (mmWave) transmission, benefiting from the reuse of the deployed passive optical network (PON) infrastructure, towards future mobile fronthaul architectures. Powerful fully programmable gate array boards located inside the access nodes convert the Ethernet-based traffic to orthogonal

Passive optical networks (PONs) have been widely used in access networks and are today the access technology of choice for operators, especially when they need to build new infrastructure. Significant effort has been put in place across the years to scale the speed of passive optical networks. The super-PON concept has also been proposed in order to scale reach and customer aggregation of PONs. However

Discrete multitone (DMT) modulation, due to its water-filling nature, is proposed to enable flexibility in passive optical networks (PONs), optimizing the PON resource usage. The use of DMT signals to directly modulate long-wavelength vertical-cavity surface-emitting lasers (VCSELs) can provide energy-efficient transmitters for 50G PONs. First, we present preliminary experimental measures employing

This paper discusses the future direction of optical access networks and proposes a new optical access architecture that will support the evolution of optical access systems from a fiber-to-the-home infrastructure to a common optical access platform that connects various devices and systems to anywhere they want to reach. We describe two technologies for its implementation. One is “modularization,”

As the capacity of the next-generation passive optical network (PON) is reaching 100 Gb/s and beyond, cost-effective transceivers have been widely discussed. In this work, we provide a comprehensive comparison of various simplified coherent and direct detection (DD) schemes operating at a ${100\; {\rm Gb/s/}}\lambda$100Gb/s/λ 4-ary pulse amplitude modulation signal through numerical simulation. According

Coherent wavelength division multiplexing (WDM) technologies have leveraged the optical communication systems in core networks, increasing the fiber capacity by transmission with advanced modulation formats and mitigation of impairments with digital signal processing. However, these solutions are too expensive for access networks, where cost, power budget, and footprint are limited. Hence, the key

Standardization activities are nearly complete for single wavelength 25 Gb/s time-division multiplexed (TDM) passive optical networks (PONs) and well underway for 50 Gb/s TDM PONs. There is considerable debate in the industry about which technology will be the “next step” after 10 Gb/s TDM PON, now finally starting to ramp up to mass deployment. 50 Gb/s PON clearly brings a ${2} \times$2× bandwidth

We propose a new automation concept for access network equipment called “Plug & Provision.” This concept aims at reducing the workload in provisioning passive optical network (PON) service by utilizing a modular optical line terminal (OLT) and automating the setup sequence. To realize this concept, the automation platform must automatically detect the modular OLT plugged into a switch port and execute

With 10G time division multiplexed passive optical network (TDM-PON) systems ready for massive deployment worldwide, the next generation PON standards are being intensively discussed in both IEEE and ITU-T. Compared with the IEEE’s wavelength stacked ${2}{ *}{25}\text{G}$2∗25G solution, the ITU-T’s single carrier non-return-to-zero-based 50G TDM-PON has the advantages of low cost, easy operation, and

This paper proposes an elastic RF-optical networking (ERON) architecture solution for millimeter wave (mmWave) 5G radio access networks. The ERON architecture achieves energy efficiency and throughput elasticity using photonic-enhanced multibeam mmWave spatial multiplexing capability at the radio units. The centralization of the hardware resources and the converged management of the RF and optical

With the stringent requirements of high reliability and low latency, ultra-reliable low latency communications (URLLCs) are one of three typical services in the fifth generation of mobile network (5G) paradigm. The packet duplication (PD) technique has been proposed as a promising solution to satisfy the extreme requirements of URLLC services. However, the benefit of PD comes at the cost of doubling

Dynamic network slicing has emerged as a promising and fundamental framework for meeting 5G’s diverse use cases. As machine learning (ML) is expected to play a pivotal role in the efficient control and management of these networks, in this work, we examine the ML-based quality-of-transmission (QoT) estimation problem under the dynamic network slicing context, where each slice has to meet a different

Elastic optical networks (EONs) are able to provide high spectrum utilization efficiency due to flexibility in resource assignment. In translucent EONs, by employing regenerators and using advanced modulation formats for transmission, spectrum efficiency can be further improved. Survivability is regarded as an important aspect of EONs, and p-cycle protection is considered to be an attractive scheme

Rapidly growing and fluctuating traffic demands lead to unbalanced traffic scenarios in optical access networks, which have an impact on network efficiency. Thus, the flexible software-defined reconfigurable passive optical network (PON) architecture has been proposed to handle this challenge. To improve the efficiency of a reconfigurable PON facing unbalanced traffic demands, this paper proposes a

The reduction of system margin in open optical line systems (OLSs) requires the capability to predict the quality of transmission (QoT) within them. This quantity is given by the generalized signal-to-noise ratio (GSNR), including both the effects of amplified spontaneous emission (ASE) noise and nonlinear interference accumulation. Among these, estimating the ASE noise is the most challenging task

In this paper, we present Alibaba’s practices and views on open and disaggregated optical transport networks, with a focus on metro data center interconnects (DCIs). We first discuss technology developments that have enabled open optical transport networks, followed by a presentation of our open optical network architecture for DCI networks. We then describe an overall data center network architecture

Multi-vendor interoperability and disaggregation are attracting the interest of network operators as a way to avoid vendor lock-in, thus opening the market and, possibly, reducing costs. NETCONF, in concert with YANG data models, has been identified as the software defined networking (SDN) configuration protocol for these networks. Currently, several YANG models describe devices in a vendor-neutral

In this paper, we describe the validation of GNPy. GNPy is an open source application that approaches the optical layer according to a disaggregated paradigm, and its core engine is a quality-of-transmission estimator for coherent wavelength division multiplexed optical networks. This software is versatile. It can be used to prepare a request for proposal/request for quotation, as an engine of a what-if

We present an open design of a filterless add/drop reconfigurable optical add/drop multiplexer module with a NETCONF northbound interface. Compared to commercial offerings, the device design is openly documented and available for detailed inspection. Performance is evaluated with up to seven adjacent high-speed 100 Gbps signals on a 50 GHz frequency grid.

Open optical networks present a variety of benefits to service providers and enterprise network operators, such as freedom from single-vendor dependence and the potential to select best-in-class solutions for each individual network role (e.g., line system or optical terminals). In this paper, we discuss two open optical network models: one enables transponder–line system interoperability, whereas

Historically, reconfigurable optical add/drop multiplexers (ROADMs) have been proprietary with respect to their data and control planes. There has been a growing desire among network operators to move away from such proprietary elements. Together with other network operators and industry partners, we have created the OpenROADM multi-source agreement and published interoperability specifications as