Because of multiple advantages such as high bandwidth, high security, and flexible networking, the free space optical communication (FSO) has attracted more and more attention. However, the narrow beam of laser and the constrained access degree of optical node limit the development of mobile FSO networks, especially in the aspect of handover. In this paper, we propose a fuzzy logic control-based handover

This paper proposes a system that aims to reduce the spectral width, Δλ, of the optical signal at transmitter for WDM system over distance 100 km. Also, a chirped fiber Bragg grating (CFBG) at the receiver is used to compensate dispersion. The proposed system consists of four cascaded FBGs connected between light source and optical fiber. Many apodization functions are investigated to enhance the performance

This paper has proposed a photonic microwave waveforms generation scheme based on a dual-polarization Mach–Zehnder modulator (DPol-MZM) at moderate modulation depth without optical filtering. In the scheme, two sub-MZMs are driven by a fundamental frequency and a frequency tripled signal, respectively, to perform the optical carrier suppression modulation along two orthogonal polarization directions

We proposed a signal demodulation method by measuring the time interval between adjacent photons and realized the recovery of the original signal from the discrete random pulse sequence output by the single-photon detector. On this basis, a new communication system model is established by comprehensively considering the photon statistical characteristics of the emitted light field, the statistical

Visible light communication (VLC) is a promising technology that addresses the bandwidth bottleneck of radio-frequency based indoor wireless networks. Optical attocell networks using VLC backhaul links have been proposed. Line-of-sight (LOS) and mirror-aided non-LOS links can be used for backhaul transmission. As the visible light spectrum is used for both access downlink and bidirectional backhaul

The present work discusses the development and simulative investigation of a high-capacity wavelength division multiplexed free space optics (FSO) transmission system. A novel 3-D orthogonal modulation scheme is proposed, which simultaneously capitalizes on different signal properties of an optical laser beam, i.e., intensity, phase, and state of polarization to transmit three independent 40 Gb/s data

Performance of underwater wireless optical communication (UWOC) with different vertical water channel conditions is experimentally analyzed. Experiment has been carried out by varying temperature and salinity of the vertical water channel. Underwater vertical channel is modeled by obtaining the best fit with the experimental data in terms of received optical power as a function of transmission depth

Orthogonal frequency division multiplexing (OFDM) is considered as one of the most significant transmission methodologies of the recent past. Moreover, it permits easy demodulation and modulation. To find the new OFDM-based waveform to be used in fifth generation which is one of the foremost open issues for wireless networks of the next generation. In addition, the OFDM is affected by the maximum Peak-to-Average

Resource allocation is a fundamental task in any PON and it is necessary to have an efficient scheme that reduces delay, maximizes bandwidth usage, and minimizes the resource wastage. A variety of dynamic bandwidth allocation (DBA) and dynamic wavelength and bandwidth allocation (DWBA) algorithms have been proposed which are based on different PONs (e.g., EPON, GPON, XG-PON, 10G EPON, etc.). But to

In this paper, we focus on energy-efficient network planning (including traffic provisioning) along with optimal placement of virtualized elastic regenerators (VERs) for IP-over-elastic optical networks based on a static traffic profile, using a mixed integer linear programming-based optimization model. The proposed model judiciously exploits flexibility of IP core routers, sliceable bandwidth variable

We propose a photonic crystal-based all-optical AND, OR, and XOR logic gates using square lattice silicon rods with air background. The design of proposed logic gates works on beam interference principle and operates efficiently by changing phase of light beams at 1550 nm wavelength. The proposed AOX logic gates are implemented with only one structure with variations in the phase of applied input signals

Flexible optical network architectures are considered a very promising solution where spectrum resources are allocated within flexible frequency grids. This paper presents a minimum spectrum utilization (SU) and average path length (APL) approach to solve the (off-line) routing and spectrum allocation problem (RSA) based on combining a simple ordering pre-computation strategy, namely most subcarriers

Quantum-dot cellular automata (QCA) is one of the most prominent technologies in nanometer-scale with appreciable reduction of size and power consumption and high switching frequency to overcome the scaling limitations of complementary metal-oxide semiconductor. On the other hand, code converters play a key role in signal processing and efficient network designs. The researchers have focused on emerging

In this paper, a new photonic crystal-based full-adder for the summation of three bits has been proposed. For realizing this device, three input waveguides are connected to the main waveguide. An optical power splitter is placed at the end of this waveguide. Concerning the amount of optical intensity inside this waveguide, two nonlinear resonant cavities transmit the waves toward the correct ports

5G networks will comprise multiple, versatile infrastructures at finest granularity consisting of multiple disaggregated pools of network, compute and storage resources. To support the 5G network architectures and satisfy the access network demanding performance requirements, transport networks consisting of various converging technologies shall provide mechanisms to support deployment flexibility

Optical communication systems (OCSs) mainly represent the backbone of modern long-haul communication networks because of low loss transmission over long distances and ultra-high capacity. However high data-rate transmission through optical fiber suffers from deterioration due to nonlinear impairments, such as four-wave mixing (FWM) in particular. At high launch power levels, which are required for

Radio frequency (RF) spectrum is already dense enough and hard to add more broadband channels to meet the current user demands. Optical free-space communications could be an excellent alternative to the RF communications system, and it provides additional benefits, e.g., large bandwidth, high data rates and reliable communication link. Therefore, free-space optical (FSO) communication system becomes

Based on the recent research, the communication cost has been the most important open issue in network on chip (NoC). In other words, the lower the communication cost, the better the performance of the NoC and the lower the energy consumption. In this regard, although different mapping algorithms are proposed, they could not efficiently address some important challenges such as high complexity, early

This work proposes a resilient wheel-based wavelength-division-multiplexed passive optical network optical access network architecture for backhauling network traffic. This proposed resilient architecture can efficiently support not only the fixed users but also the mobile users in the downstream direction under normal and failure operating scenarios, while minimizing the average traffic delivery time

Add–drop filter (ADF) is a key component in optical integrated circuits that can be used in all-optical communication networks and wavelength division multiplexing (WDM) systems. The quality factor, coupling efficiency, transmission efficiency and coupling length are important parameters in add–drop filters. Photonic crystal (PC) optical devices have become popular among researchers because their structure

This paper focuses on a Centralized Radio Access Network solution adopting the concept of resource disaggregation. In this context, it proposes a heuristic suitable to optimally assign Base Band Unit processing functions in softwarized Radio Access Networks to different servers, taking into consideration their processing requirements with the aim to minimize the overall energy consumption. It also

To address the limitations of current radio access networks (RANs), centralized RANs adopting the concept of flexible splits of the BBU functions between radio units (RUs) and the central unit have been proposed. This concept can be implemented combining both the Mobile Edge Computing model and relatively large-scale centralized Data Centers. This architecture requires high-bandwidth/low-latency optical

In this paper, a 1 × 2 optical switch based on two TE/TM polarization converters, one 1 × 2-polarization beam splitter and a hybrid 2 × 2-polarization beam splitter/combiner is designed and discussed. The novelty of this work resides in the design of a 2 × 2-hybrid polarization beam combiner/splitter, operating as a 2 × 2 polarization optical switch through the combining and the splitting of polarized

In hybrid free space optical/radio frequency (FSO/RF) systems, switching between the optical and RF links depends on the optical and RF signal to noise ratio (SNR) threshold levels; therefore, the correct choice of these threshold levels is essential to make best use of the complementary nature of optical and RF links. Optimal selection of these threshold levels is the prime objective of this paper

Spectrum fragmentation has always been a major issue to overcome toward spectrally efficient Flex-Grid over Single-Mode Fiber dynamic optical networks and continues like so when evolving to Flex-Grid over Spatial Division Multiplexing (SDM). A possible strategy to eliminate its pernicious effects is to divide the available spectrum into several partitions, dedicating each one of them to only support

Integration of electromagnetic (EM) wave absorber with patch antenna array on single substrate provides a very efficient way to improve the radiation pattern of array by reducing mutual coupling effect. The placing of absorber on array assembly may however affect the radiation characteristics due to the heat generated from absorbed power. As the microwave absorber dissipates the inter-element waves

Low-cost low-margin implementation plays an essential role in upgrading optical metro networks required for future 5G ecosystem. In this regard, low-resolution analog-to-digital converters can be used in coherent optical transponders to reduce cost and power consumption. However, the resulting transmission systems become more sensitive to physical layer fluctuations like the events caused by fiber

Transport network virtualization provides the necessary data and control plane technologies as key enablers of future networks. The interaction between network slicing and optical transport network virtualization architectures is under study to automate effective network resource orchestration. In this paper, we present an harmonized network slicing and transport network virtualization architecture

Physical topologies are evolving from elementary survivable rings into complex mesh networks. Nevertheless, no topology model is known to provide an economic, systematic, and flexible interconnection paradigm for ensuring that those meshes bear resilience features. This paper argues that intrinsic resilience can be brought by twin graph topologies, as they satisfy equal length disjoint path property

In this work, an eavesdropping-aware routing and spectrum allocation approach is proposed utilizing network coding (NC) in elastic optical networks (EONs). To provide physical layer security in EONs and secure the confidential connections against eavesdropping attacks using NC, the signals of the confidential connections are combined (XOR-ed) with other signals at different nodes in their path, while

Network services in 5G will be rolled out as pools of virtual network functions (VNFs) exploiting the advantages of both software-defined networking and network function virtualization. In this context, 5G network services are envisaged as ordered sequences of VNFs resulting in the so-called VNF Forwarding Graphs (VNFFGs). Such VNFs can be allocated over a number of distributed but interconnected data

Optical packet switching is a prominent technology proposing not only a reduction in the energy consumption by the elimination of numerous optical–electrical–optical conversions in electronic switches, but also a decrease in network latencies due to the cut-through nature of packet transmission. However, it is adversely affected by packet contention, preventing its deployment. Solutions have been proposed

Optical multi-domain transport networks are often controlled by a hierarchical distributed architecture of controllers. Optimal placement of these controllers is very important for efficient management and control. Traditional SDN controller placement methods focus mostly on controller placement in datacenter networks. But the problem of virtualized controller placement for multi-domain transport networks

Emerging inter-datacenter applications involving data transferred, processed, and analyzed at multiple datacenters, such as virtual machine migrations, real-time data backup, remote desktop, and virtual datacenters, can be modeled as virtual network requests that share computing and spectrum resources of a common substrate physical inter-datacenter network. Recent advances make elastic optical networks

Functional splitting, referred as X-haul, is introduced in the 5G networks to support flexibility and meet service requirements. Each split option has a different impact on latency and bandwidth characteristics. Depending on the split, a certain amount of redundant resources is required to provide resiliency against outages or failures, as in the case of the uRLLC service. This paper proposes novel

To achieve fast recovery of optical transport networks after a disaster, we investigate a novel scheme enabling cooperation between carriers. Carriers can take advantage of their surviving or recovered optical resources to aid each other through an emergency lightpath support, thereby efficiently reducing the recovery burden, which can be heavy immediately after a disaster. Such lightpaths can be exclusively

Network Slicing appears as one of the enabling technologies for 5G networks to accommodate services with different requirements and availability. The present work seizes the use of network slicing and focuses on the deployment and maintenance of services which are sensitive to latency constraints. For this purpose, the design and use of a VNF latency sensor are presented, considering its aggregation

A novel an optical four-channel demultiplexer based on a hexagonal lattice shape of embedded air holes in dielectric substrate (air-bridge type) is proposed. Demultiplexing for each channel is obtained by designing the graphite-type ring resonator which consists of small air hole defects in own unit cells. The physical parameters which govern the demultiplexer performance are investigated. It is observed

In this present work, photonic crystal based ultra-high-speed encoder is proposed for optical computing applications. The designed logic device contains dual nanocavity coupled ring resonator, reflector and five waveguides in a square lattice with barium titanate rods arranged in a nanostructure platform. The encoding device is working based on the interference and resonance effect. The photonic band

Filterless optical networks (FONs) have been proposed as a feasible solution for optical metro networks. In addition, as a result of the shorter distance compared to core optical networks, direct detection optical transmission systems can be used in metro FONs, which reduces costs, as compared to coherent detection systems. In this work, we present two optical signal tracking approaches for FONs that

We review the most important WDM system innovations motivated by the evolution of DCI transport. State-of-the-art coherent transmission has already exceeded 6 b/s/Hz in transatlantic deployments. Moreover, the adoption of software innovations in automation and programmability, which DCI pioneered in transport networks, has also simplified operations and enables the emergence of open transport architectures

In this paper, we derive the theoretical lower and upper bounds for bit error rate (BER) for spectral amplitude coding OCDMA balanced detector (BD) employing multiple photodiodes. The purpose of this study is to find the maximum performance improvement that can be achieved when a multi-photodiode structure is used to reduce the intensity noise. Results show that when the split signals are independent

For serving futuristic applications like distributed robotic systems with robots equipped with humanoid intelligence, wireless access to high-performance computing resources should be provided. For this purpose, a very dense wireless network, referred to as attocell network, consisting of radio cells typically less than 1 m\(^{2}\), and antennas integrated in the floor tiles has been proposed. To serve

In this paper, an analytical approach is presented to investigate the bit error rate (BER) performance of underwater wireless optical code division multiple access system for different water types. Optical orthogonal codes (OOC) are used as the user-specific address sequence to encode and decode the user’s data. LED with an operating wavelength of 532 nm is used as the optical source, and silicon avalanche

Power compensation is the main challenging issue for dense optical communication system because it affects the signal strength, and subsequently, performances of the received signals are degraded. So in this recommended research work, we have resolved this challenge for 12-Gbps dense communication systems (DWDM) with 80 channels using the three power compensation approaches (pre-power compensation

In this paper, a novel two dimensional (2D) wavelength/time (W/T) optical code division multiple access (OCDMA) code with zero cross-correlation property to minimize multiple access interface (MAI) is addressed. The code is constructed using various features of two different one-dimensional codes, i.e., multi-diagonal code and prime hop code referred as multi-diagonal prime hopping (MDPHC) code. The

A uniform fiber Bragg grating sensor is sketched and inspected by the finite-difference time-domain method in furtherance of obtaining ultimate transmission and reflection spectra by optimizing the FBG parameters like refractive index, grating height, grating width, wafer width, wafer length. The maximum transmission power spectrum is achieved as − 7 dB for the refractive index of 3.005, and the maximum

Ultraviolet and mid-infrared (MIR) constitute two extreme ends of the optical wireless communication band. Recently, there has been a rise in increased interest for research in these two spectral bands. For successful deployment of these technologies, the performance of these two spectrum bands needs to be thoroughly analyzed. We consider turbulence and noise effects over these spectral bands. Specifically

In this study, simple basic plasmonic logic gates of XOR, OR, and NOT based on graphene nano-ribbon resonators coupled to properly designed arrangements of nano-waveguides, as input and output logic ports, are demonstrated. The operation of the structures as frequency selective components is based on the propagation of edge modes in nano-waveguides and coupling to nano-ribbon resonators located in

This paper proposes generalized frequency division multiplexing (GFDM) for indoor visible light communication (VLC). GFDM is a flexible multi-carrier scheme that allows engineering in both time and frequency domain, therefore, making GFDM suitable for various 5G applications. In the literature, different types of optical orthogonal frequency division multiplexing (O-OFDM) have been proposed for VLC

An eight-channel wavelength demultiplexer by cascading of ring resonators (RRs) in photonic crystal (PhC) structure is proposed in this paper. In designing of this demultiplexer, we used eight square-shaped PhC RRs with different refractive index (RI) of defect rods to generate a distinctive resonance wavelength. Each PhC RR has a specific resonance wavelength with tuning a variety of design parameters

Translucent optical networks use sparsely located regenerator nodes to increase the optical reach, otherwise limited by the physical layer impairments. Routing in translucent networks often causes the lightpath to traverse a fiber more than once, requiring the use of multiple wavelengths on a fiber for the same lightpath. Most of the routing and wavelength assignment (RWA) algorithms for static demand

The study of one-way edge states of electromagnetic wave based on quantum Hall effect in photonic crystals (PCs) has recently made a great progress. In particular, the pseudo-spin states in topological PCs made of dielectric materials can be realized by breaking pseudo-time-reversal symmetry. We perform a research on the influence of parameters, such as lattice constant, dielectric permittivity of

A full-duplex optical fiber/wireless single-channel coherent communication system is presented for high-speed data center interconnections. In-phase and quadrature modulator (IQM)-based dual polarization 256 quadrature amplitude modulation (DP-256-QAM) is implemented to achieve a maximum data rate of 640 Gbps with 40 Gbaud symbol rate for both the single-mode fiber (SMF) and free-space optics (FSO)

The problem of regenerator assignment (RA) in translucent optical networks consists in segmenting a lightpath into several transparent segments, each of which linked by 3 R regenerators. In this article, we present two heuristics and compare their effectiveness with an exhaustive method to solve the RA problem in translucent elastic optical networks under dynamic traffic. The exhaustive method is capable

Optical network-on-chip (ONoC) is a new designing of multi-processor system-on-chip. On the one hand, global bus is a simple and common logical topology for ONoC. On the other hand, the parallel formulation of bitonic sorting has lower time complexity than the sequential implementation of bitonic sorting. Thus, it is meaningful to study the parallel implementation for bitonic sorting on bus ONoC. Different

Quantum key distribution aims to distribute a secret key among distant parties linked by an optical fiber or free space. Unfortunately, the main problem which limits the long distance direct transmission of qubits is the exponential decay of the signal. This limit can be overcome by introducing quantum repeaters (QRs) between the two distant points. Quantum repeaters suggest a technique for establishing

This paper depicts the design of 0.55 Tb/s heterogeneous Flexi-rate Nyquist-wavelength division multiplexed (Nyquist-WDM) Superchannel. Here, for the first time, four subcarriers of different modulation formats are accommodated, namely polarization multiplexed-binary phase-shift keying, polarization multiplexed-quadrature phase-shift keying (PM-QPSK), polarization multiplexed-8-quadrature amplitude

A new terahertz isolator based on the ferromagnetic resonance effect is suggested and analyzed. A two-dimensional photonic crystal consisting of a square lattice of gallium arsenide rods has been employed in the design of the device. Incident electromagnetic waves interact with one magnetized ferrite rod and two stubs inserted in the photonic crystal structure, generating a vortex-like field profile

The ever-increasing communication requirements have led to the introduction of optical circuit switch (OCS) to data center, which is capable of providing more flexible bandwidth allocation compared to the electrical packet switching. However, the challenge still arises due to non-negligible reconfiguration delay of commercially available MEMS-based optical circuit switching technology, even though