Optical Communication Networks Research Articles

Enhancing Gain Uniformity in WDM Networks Across C and L Bands Through Hybrid Optical Amplifier Integration

This study explores strategies for optimizing EDFA gain in the context of (WDM and DWDM systems. By reviewing recent literature, we investigate various approaches to enhance EDFA performance, considering factors such as input power, pump power, and fiber length. Our analysis covers optimization algorithms, gain flattening techniques, adaptive gain equalization methods, and hybrid amplifier configurations. Additionally, we examine studies addressing nonlinear effects and the allocation of pump power to maximize gain efficiency. Recent advancements, including machine learning-based approaches and novel gain equalization techniques using phase-shifted fiber Bragg gratings, are also discussed. The findings underscore the significance of tailored EDFA gain optimization methods for improving the overall performance and efficiency of WDM and DWDM systems in optical communication networks.

Numerical investigation of plasmon-enhanced emission from a nanofiber coupled single photon emitter

This study explores the enhancement of emission from a single photon emitter in a quantum communication network by coupling the source with an optical nanofiber and leveraging gold nanoparticles for Purcell enhancement. Large Purcell enhancements of more than 50 times were recently reported experimentally, but the understanding of important issues, including the maximum Purcell factor and limits to quantum efficiency due to ohmic losses, is still lacking. Our findings reveal that the reported experimental results are reasonable, and confirm that such composite devices provide a promising route for high-efficiency single photon sources coupled to an optical fiber-based quantum communication network.

Dynamic Spectrum Assignment in Passive Optical Networks Based on Optical Integrated Microring Resonators Using Machine Learning and a Routing, Modulation Level, and Spectrum Assignment Method

The rising demand for bandwidth in optical communication networks has led to the need for more efficient solutions for spectrum allocation. This article presents a solution to enhance the capacity and efficiency of passive optical networks (PON) using optical microring resonators and dynamic spectrum allocation. The solution relies on wavelength division multiplexing (WDM). It proposes using a support vector machine (SVM) and a Routing, Modulation Level, and Spectrum Assignment (RMLSA) method to manage spectrum allocation based on the bandwidth and distance of multiple requests. The network employs a pulse shaper to physically allocate the spectrum, allowing for the separation of the spectrum generated by the microring resonators into different wavelengths or wavelength ranges (super-channel). Additionally, the SVM and RMLSA algorithms regulate the pulse shaper to execute the allocation. This photonic network achieves improved spectrum utilization and reduces the network blocking probability. Our proposal shows that we successfully addressed 1090 requests with a zero blocking probability, accounting for 81% of the total requests. These request scenarios can simultaneously accommodate up to 200 requests, with a maximum bandwidth of 31 THz. This highlights the efficacy of our approach in efficiently managing requests with substantial processing capacity.

Design and characteristics study of bend-resistant and low-crosstalk few-mode multi-core fiber

This study introduces a novel 9-core, 4-mode fiber characterized by its bend resistance and minimal crosstalk. Utilizing a hetero-core scheme, the cores are effectively isolated through trenches and air holes, significantly reducing inter-core crosstalk. The cores are strategically arranged in a square array to facilitate easier splicing. Through comprehensive simulation calculations, it is demonstrated that four LP modes can be consistently transmitted within the C+L band. The effective refractive index difference between adjacent modes exceeds 10−3, ensuring negligible intra-core crosstalk. Concurrently, the inter-core crosstalk of the LP02 mode is maintained below − 40 dB/100 km. The fiber's bending radius can be minimized to 60 mm without compromising performance, with the corresponding bending loss for the LP02 mode in the two outer cores measured at 1.6 × 10−5 dB/m and 3.95 × 10−6 dB/m, respectively. Each of the nine cores exhibits an effective mode area exceeding 95 µm2, and the fiber's relative core multiplexing factor at 1550 nm is 27.62. The proposed fiber's superior performance positions it as a promising solution for practical applications in optical fiber communication networks, potentially addressing the burgeoning capacity crisis in communication systems.

Integrated Optical Sensing and Communication (IOSAC) System Based on Hybrid‐Waveguide Structures

AbstractAdvanced silicon photonic technologies enable integrated optical sensing and communication (IOSAC) in real time for the emerging application requirements of simultaneous sensing and communication for next‐generation networks. Herein, an IOSAC system is proposed and demonstrated on the silicon nitride (Si3N4) photonics platform. The IOSAC devices leveraging microring resonators excel in real‐time monitoring of analyte fluctuations and efficiently transmit this data to the terminal, positioning them as viable alternatives to bulk optics in applications that demand both high precision and speed. By directly integrating Si3N4 ring resonators with optical communication networks, simultaneous sensing and optical communication are demonstrated by an optical signal transmission experimental system using especially filtering amplified spontaneous emission spectra. The refractive index (RI) sensing ring with a sensitivity of 172 nm RIU−1, a figure of merit (FOM) of 1220, and a detection limit (DL) of 8.2 × 10−6 RIU is demonstrated. Simultaneously, the 1.25 Gbps optical on‐off‐keying (OOK) signal is transmitted at the concentration of different NaCl solutions, indicating the bit‐error‐ratio (BER) decreases with the increase in concentration. The novel IOSAC technology shows the potential to realize high‐performance simultaneous biosensing and communication in real time and further accelerate the development of IoT and 6G networks.

Low crosstalk 125 μm cladding heterogeneous six-core few-mode fiber with air-hole array and trench structure

In order to be compatible with the current optical fiber communication network, we propose a 125 μm diameter heterogeneous six-core two linear polarization modes fiber with air-hole array and trench (HAT) structure. The coupled power theory and finite element method (FEM) are used to investigate inter-core crosstalk (ICXT), bending loss, and other properties. The HAT structure can effectively suppress ICXT; and the maximum ICXT is less than −38 dB/100 km in C + L band. The effective refractive index difference (Δneff) between modes is greater than 3 × 10-3, inter-mode crosstalk (IMXT) can be ignored. The maximum intrinsic loss is 0.187 dB/km; relative core multiplicity factor reaches 32.21. The relative spatial efficiency is 18 times that of traditional single-mode fibers. This fiber can be produced by chemical vapor deposition and existing optical fiber manufacturing technology. The designed fiber can be directly connected to the communication network to reduce the cost of equipment renewal, and the communication capacity can be increased by 18 times.

Generation of Orbital Angular Momentum Light by Patterning Azopolymer Thin Films

Orbital angular momentum (OAM) encoding is a promising technique to boost data transmission capacity in optical communications. Most recently, azobenzene films have gained attention as a versatile tool for creating and altering OAM-carrying beams. Unique features of azobenzene films make it possible to control molecular alignment through light-induced isomerization about the azo bond. This feature enables the fabrication of diffractive optical devices such as spiral phase plates and holograms by accurately imprinting a phase profile on the incident light. By forming azobenzene sheets into diffractive optical elements, such as spiral phase plates, one can selectively create OAM-carrying beams. Due to the helical wavefront and phase variation shown by these beams, multiple distinct channels can be encoded within a single optical beam. This can significantly increase the data transmission capacity of optical communication systems with this OAM multiplexing technique. Additionally, holographic optical components made from azobenzene films can be used to build and reconstruct intricate wavefronts. It is possible to create OAM-based holograms by imprinting holographic designs on azobenzene films, which makes it simpler to control and shape optical beams for specific communication requirements. In addition, azobenzene-based materials can then be suitable for integration into optical communication devices because of their reconfigurability, compactness, and infrastructure compatibility, which are the main future perspectives for achieving OAM-based technologies for the next generation, among other factors. In this paper, we see the possible use of azobenzene films in the generation and modification of OAM beams for optical communications through light-induced isomerization. In addition, the potential role of azobenzene films in the development of novel OAM-based devices that paves the way for the realization of high-capacity, OAM-enabled optical communication networks are discussed.

Mitigating network adaptation and QoT prediction challenges in WDM networks

Abstract The capacity and efficiency of optical communication networks have been completely transformed by wavelength division multiplexing (WDM) technology, which allows many wavelengths to be transmitted simultaneously over a single optical fibre. Conventional QoT prediction is based on analytical models that consider physical layer characteristics including dispersion, optical power and signal-to-noise ratio. But these models frequently oversimplify complex real-world situations, which reduces their accuracy for modern high-speed WDM networks. A data-driven solution is provided by machine learning(ML), which may boost the accuracy of QoT predictions by utilising real-time measurements, historical data and a variety of network situations. The creation of a ML-based framework for QoT prediction is investigated in the current research. This research proposes an effective ML-based routing computation model that uses a non-linear autoregressive recurrent neural network (ML-RCNA-RNN) to ensure QoT for every wavelength channel in high-capacity and high-speed WDM networks. Through simulations, more accurate QoT metrics, such as bit error rate (BER) 68.42 %, QoT prediction accuracy (Q-Factor) 5.9 %, network adaption time (ms) 48.3 %, latency (ms) 0.28 % and throughput (Gbps) 14.29 %, have been obtained compared to conventional QoT predictions. These results were obtained using Gaussian noise Python simulation (GNPy). As a result, the proposed framework that makes use of GNPy demonstrates that it substantially enhances optical communication networks’ performance and dependability. This facilitates the development of high-capacity, low-latency and reliable communication infrastructure, and makes it more adaptable and able to manage the complexity of high-speed WDM optical networks while preserving signal quality in the modern digital era.

Analysis of 256-QAM optical OFDM-NOMA signal detection using beam forming

Abstract The incessant growth of data demand in modern communication systems has spurred the quest for innovative technologies capable of delivering higher data rates, improved spectral efficiency, and enhanced quality of service. This research focuses on the synergistic integration of three cutting-edge technologies: 256-QAM (quadrature amplitude modulation), NOMA (non-orthogonal multiple access), and hybrid beamforming within the optical OFDM (orthogonal frequency division multiplexing) framework. The aim is to investigate their combined potential for revolutionizing optical communication networks and meeting the escalating demands of 5G and beyond. The methodology employed in this research entails extensive simulations and analytical assessments to gauge the performance of the proposed system under diverse channel conditions and operational scenarios. Metrics such as bit error rate (BER), spectral efficiency, and capacity are scrutinized to provide insights into the system’s efficiency and scalability. The amalgamation of 256-QAM, NOMA, and hybrid beamforming is expected to yield exponential gains in spectral efficiency, thereby optimizing the utilization of precious spectral resources. Reduced latency is pivotal for an array of real-time applications such as autonomous vehicles and augmented reality. This research aims to minimize latency, ensuring timely and responsive data transmission.

Resource allocation with fuzzy logic based network optimization and security analysis in optical communication network

Resource allocation with fuzzy logic based network optimization and security analysis in optical communication network

On-orbit space optical communication demonstration with a 22 s acquisition time.

The inherent small divergence angle of space optical communication poses significant challenges to establishing communication links. Therefore, laser link acquisition becomes a crucial technology in optical communication, with a primary focus on reducing the acquisition time effectively. Conventional optical communication acquisition techniques fail to address the error effects caused by satellite insertion into the Earth orbit, thus unable to meet the rapid establishment demands of laser links in satellite optical communication networks. In this regard, we propose a novel, to the best of our knowledge, on-orbit calibration method for laser communication terminals to our knowledge. Leveraging stellar observations, this method achieves efficient on-orbit calibration with only a single observation. Theoretical analysis and on-orbit experimental results demonstrate that this approach effectively enhances an open-loop pointing accuracy, offering promising prospects for achieving a rapid establishment of optical communication links in ultra-long-distance optical communication missions.

Characteristics Analysis of Hybrid Optical Amplifier with Doped Fiber Variations for Fiber Optic Communications Network

Optical communication networks are vital in the digital era, but data transmission becomes weak the longer the distance traveled by light. Erbium-Doped Fiber Amplifier (EDFA) technology is commonly used as an optical amplifier, but it still produces a small gain, Q-factor, and a significant noise figure. This study characterized the Hybrid Optical Amplifier (HOA) combinations that contain EDFA with various doped fibers. The characterization was performed through Optisystem software simulation by observing and analyzing the gain, noise of figure, and Q-factor generated by each doped fiber variant. The results showed that the combination of Ytterbium-doped Fiber produced the most significant gain of 15.83 dB, less noise figure of 5,661 dB, and a relatively high Q-factor of 35,615 at 1,550 nm. It indicates that the HOA combination is suitable and ideal for long-distance transmission in fiber optic communication network applications.

Performance analysis of NGPON using hybrid GPON-XGPON based robust long-haul passive optical communication network

Abstract For high data rates and extended reach capabilities, communications networks need to be enhanced by employing passive optical networks (PONs). NG-PON plays a key role in achieving the modern demands. This paper proposed novel hybrid G-PON and XG-PON based robust long-haul Passive Optical Communication Network. In this proposed network hybrid semiconductor optical amplifier (SOA) and EDFA are used to enhance the system performance for downstream (D.S.) and upstream (U.S) signals transmission. This paper analyses a hybrid G-PON and XG-PON bi-directional optical fiber link up to length of 100-km with a 128 (1:64 and 1:64) way-splitter to increase the coverage area and to enhance the quality of transmitted data. The qualitative analysis of the proposed network shows an improved performance in terms of transmission distance, quality factor and eye-diagrams.

Obliquely propagating optical wave patterns to the (2 + 1)-dimensional chiral nonlinear Schrödinger equation in the absence and presence of Atangana derivative

The study aims to explore obliquely propagating optical wave solutions to the (2 + 1)-dimensional chiral nonlinear Schrödinger (NLS) equation in both the absence and presence of the Atangana derivative. In order to convert the classical-order chiral nonlinear Schrödinger equation to an ordinary differential equation, a transformation associated with wave obliqueness is applied. Hereafter, the unified method is applied to the reduced equation. As outcomes, the dark, periodic singular with unequal wave length, periodic with equal wavelength, periodic, unsmooth periodic, singular periodic soliton solutions are received to the ordinary differential equation. Later, the acquired solutions are then put to the applied transformation associated with obliqueness. Moreover, the fractional-order chiral NLS equation is solved by using the spatiotemporal Atangana derivative with oblique wave transformation and the unified method. In terms of wave obliqueness, fractionality, and applied technique sense, all generated wave solutions are revealed to be novel. Along with their physical explanations, the impacts of obliqueness and fractionality on the solutions are graphically illustrated. It is exposed that as obliqueness and fractionality increase, the optical wave phenomena change. Additionally, it is discovered that the employed method can be used to obtain novel optical soliton features to the chiral nonlinear Schrödinger equation with or without fractional and obliqueness constraints. It can be assured that the utilized method is more powerful than the other methods. As a result, the method can be used in future research to explain the many physical phenomena that arise in optical fiber communication networks.

Intelligent optical transceiver technology based on federated learning traffic prediction

With the development of optical network, modern optical network needs better performance. Because the traditional optical transceiver technology has a delay according to the flow switching transmission configuration, the delay optical network service still adopts the original configuration transmission, so a certain degree of frequency spectrum resources waste and high blocking rate will be caused. The above situation can be improved if the transmission configuration can be deployed in advance based on the predicted traffic. Federated learning is a scheme of distributed training model, which can train the traffic prediction model in distributed way under the premise of ensuring the privacy of client data, which is very suitable for the traffic prediction of optical network terminals. This paper proposes an intelligent optical transceiver technology based on federal learning traffic prediction, applies the federal learning on the traffic prediction of optical communication network terminal, distributed training traffic prediction model, and deploy the optical transceiver early transmission configuration such as modulation format and baud rate parameters, thus to weaken the delay of optical transceiver technology, reduce the network blocking rate and improve the transmission performance of optical network.

Deep-Reinforcement-Learning-Based Joint 3-D Navigation and Phase-Shift Control for Mobile Internet of Vehicles Assisted by RIS-Equipped UAVs

Unmanned aerial vehicles (UAVs) are utilized to improve the performance of wireless communication networks (WCNs), notably, in the context of Internet-of-things (IoT). However, the application of UAVs, as active aerial base stations (BSs)/relays, is questionable in the fifth-generation (5G) WCNs with quasi-optic millimeter wave (mmWave) and beyond in 6G (visible light) WCNs. Because path loss is high in 5G/6G networks that attenuate, even, the line-of-sight (LoS) communicating signals propagated by UAVs. Besides, the limited energy/size/weight of UAVs makes it cost-deficient to design aerial multi-input/output BSs for active beamforming to strengthen the signals. Equipping UAVs with the reconfigurable intelligent surface (RIS), a passive component, can help to address the problems with UAV-assisted communication in 5G and optical 6G networks. We propose adopting the RIS-equipped UAV (RISeUAV) to provide aerial LoS service and facilitate communication for mobile Internet-of-vehicles (IoVs) in an obstructed dense urban area covered by 5G/6G. RISeUAV-aided wireless communication facilitates vehicle-to-vehicle/everything communication for IoVs for updating IoT information required for sensor fusion and autonomous driving. However, autonomous navigation of RISeUAV for this purpose is a multilateral problem and is computationally challenging for being optimally implemented in real-time. We intelligently automated RISeUAV navigation using deep reinforcement learning to address the optimality and time complexity issues. Simulation results show the effectiveness of the method.

A Quantum-Behaved Heterogeneous Topology Optimization Model For Optical Wireless Communication Networks

A Quantum-Behaved Heterogeneous Topology Optimization Model For Optical Wireless Communication Networks

A hybrid $${Q}_{L}$$ ANN model designed to improve the Quality of Transmission of optical communication network

A hybrid $${Q}_{L}$$ ANN model designed to improve the Quality of Transmission of optical communication network

TiN/Ti3C2 Heterojunction Microfiber-Enhanced Four-Wave Mixing-Based All-Optical Wavelength Converter

As a novel nanomaterial, the TiN/Ti3C2 heterojunction has been demonstrated to possess exceptional optoelectronic properties, offering significant potential for applications in fields such as communication, optical sensors, and image processing. The rapid evolution of the internet demands higher communication capacity and information processing speed. In this context, all-optical wavelength conversion, a pivotal technique in all-optical signal processing, holds paramount importance in overcoming electronic bottlenecks, enhancing wavelength utilization, resolving wavelength competition, and mitigating network congestion. Utilizing the idle light generated through the four-wave mixing (FWM) process accurately mimics the bit patterns of signal channels. This process is inherently rapid and theoretically capable of surpassing electronic bottlenecks with ease. By placing an optical filter at the fiber output end to allow idle light passage while blocking pump and signal light, the output becomes a wavelength-converted replica of the original bitstream. It has been verified that TiN/Ti3C2 heterojunction-coated microfiber (THM) exhibits outstanding third-order nonlinear coefficients. Building upon this, we achieved a THM-enhanced FWM all-optical wavelength converter, resulting in a ~4.48 dB improvement in conversion efficiency. Compared to conventional high-nonlinear fibers, this compact device significantly reduces fiber length and can be easily integrated into current high-speed optical communication networks. It demonstrates broad prospects in the realms of all-optical signal processing, robotic applications, ultra-high-speed communication, and beyond.

Demonstration of a switched CV-QKD network

A quantum channel is a physical media able to carry quantum signals. Quantum key distribution (QKD) requires direct quantum channels between every pair of prepare-and-measure modules. This requirement heavily compromises the scalability of networks of directly connected QKD modules. A way to avoid this problem is to introduce switches that can dynamically reconfigure the set of connections. The reconfiguration of a quantum channel implies that the modules using it can adapt to the new channel and peer.The maturity and flexibility of continuous-variable QKD (CV-QKD) qualifies it as a strong contender for integration into optical communication networks. Here we present the implementation of a switched CV-QKD network embedded in the Madrid quantum testbed. The optical switching of the quantum paths significantly reduces the amount of required QKD modules and facilitates the scalability of the network. This demonstration highlights the flexibility and ease of integration of this emerging technology.