Dense Wavelength Division Multiplexing Networks Research Articles

A non-volatile optical filter based on a Ge2Sb2Te5-assisted microring with a tunable bandwidth and extinction ratio

A novel non-volatile optical filter with a large bandwidth (BW) and extinction ratio (ER) tunability is first experimentally demonstrated by introducing an all-optical phase change of Ge2Sb2Te5 (GST). The Si-GST hybrid device promises flexible multi-level regulation of essential filter parameters in an ultra-compact footprint of 30 μm × 13 μm. Ultra-low power consumption is realised on account of the saving of external static power that is required in other electric-optic or optic-optic-driven filters. The GST is loaded onto two triple-waveguide directional couplers located at the coupling regions of an add-drop microring resonator. By initiating the GST phase transition with pump optical pulses, the transmitted optical power to the cross port of the triple-waveguide coupler is adjustable, hence influencing the coupling efficiency states of the microring filter. Consequently, a tunable on-off ER from 0.7 dB to 18.2 dB and a tunable BW from 0.6 nm to 3.3 nm are experimentally obtained with the aid of optically manipulating the crystallization degree of GST. Our device potentially enables the realisation of high-density photonic integrated circuits, especially in dense wavelength division multiplexing networks.

Hybrid amplifier placement in mesh DWDM networks using integer linear programming models

Hybrid erbium-doped fiber (EDF)/Raman amplifiers (HFAs) can be utilized to improve the performance of specific fiber spans in dense wavelength division multiplexing (DWDM) networks, aiming to extend the reach and/or increase the capacity of optical channels, thereby reducing the total number of line interfaces required to satisfy a given set of traffic demands. However, HFAs are costlier than simpler EDF amplifiers (EDFAs) since they include Raman pumps in addition to an EDFA. Consequently, it is paramount to place them only at selected fiber spans of the network so as to maximize their impact while keeping their number limited. It has been shown that HFA placement can be a complex task in mesh DWDM networks in view of optical channel diversity, with each fiber span traversed by multiple channels with different source and destination nodes. Building on the approximation that noise adds up incoherently along the transmission path, this paper proposes optimal methods to solve the problem of placing hybrid amplifiers in mesh networks. Particularly, it describes two integer linear programming models, one to determine the minimum number and location of HFAs required to reach a target set of feasible optical channels (i.e., without intermediate 3R regenerators) and another to maximize the number of feasible optical channels given a limited number of HFAs to be deployed. A comprehensive set of network simulations using three reference optical network topologies is reported, providing insight into the effectiveness of the proposed models when compared to existing approaches.

Optical label-based cost-effective DWDM optical network performance monitoring using low-bandwidth PD with novel SRS mitigation DSP

Large-scale dense wavelength division multiplexing (DWDM) multi-channel performance monitoring is one of the indispensable technologies for the flexible optical networks. The existing Labelbased monitoring scheme requires expensive optical demultiplexing components/equipment to avoid the influence of stimulated Raman scattering (SRS), which is not only costly and bulky, but also could not monitor the wavelength channels simultaneously. In this paper, a low-cost, high-accuracy monitoring scheme based on Optical Label Method is proposed for DWDM networks, where the optical channel power and node identification (ID), as the main monitoring targets that both can indicate or evaluate the channel connection status, could be efficiently monitored. In the scheme, a novel digital signal processing (DSP) method of SRS mitigation is proposed and demonstrated, and an asynchronous code-division multiple access (A-CDMA) based digital label encoding and decoding method is adopted to distinguish the node ID so that channel initial added node can be accurately verified, thereby wavelength connection status can be reliably monitored by combining the channel power and node ID information. The simulation results show that each wavelength channel power and node ID can be accurately monitored only by low bandwidth photoelectric detector (PD) under the condition of 80 wavelengths and 10 spans at C-band.

PERENCANAAN JARINGAN TRANSPORT DENSE WAVELENGTH DIVISION MULTIPLEXING (DWDM) MENGGUNAKAN APLIKASI CISCO PACKET TRACER

Communication and information technology plays a very important role in various activities. Data communication which is part of a technological development, provides enormous benefits great for its users to expedite activities. For example in activities shipping goods using sea transportation which integrates various components for the shipping process, has used data communication models both offline and online. Based on the data communication flow, one of which includes transmission, namely Dense Wavelength Division Multiplexing (DWDM) which is a network that is transmit by a single optical fiber in order to keep growing which serves to load several waves in various sizes. This article is made to find out more regarding DWDM, as well as understanding DWDM simulations using applications as planning from the DWDM network. The method used is to make a plan using Cisco Packet Tracer application, which is then analyzed from the results of reading the literature based on journals and books.
 

Efficient design of a Raman amplified wavelength division multiplexed communication network at 1330 nm

Abstract From the advent of communication, there has been a constant demand for increasing communication capacity. In optical communications, capacity can be increased by implementing more fibers or can be increased by using the same fiber to transmit more than one signal. The process is known as the wavelength division multiplexing or WDM. Channels placed closer to each other in the wavelength scale leads to the process of DWDM or dense WDM networks. But with so many channels transmitted together over minimum distances of 10 km, the power of each channel decreases significantly within the fiber, hence a Raman amplification system has been incorporated within the network. The whole system is designed at the 1300 nm optical window which has shown the least dispersion among the other optical windows. Results from simulating a 16 channel network with 8 optical pumps, where all are configured in co and counter propagating directions. They have shown good amount of gain, relatively low noise and good SNR over the whole communication band of channels rendering the system to be a faithful communication network.

Optical Cable Backbone Network Design In The Province Kalimantan East Use Technology DWDM OTN

In designing the backbone network for the province of East Kalimantan using Dense Wavelength Division Multiplexing (DWDM) and Optical Transport Network (OTN) devices which cover 10 districts and cities consisting of 34 segments, of which 34 segments consist of 10 OTN DWDM sites and 16 Optical Land Amplifier sites ( OLA). From the results of the design and simulation of the backbone network, it was found that the value of the Optical Link Power Budget (OLPB) < 50 dBm where this value is the ideal value in deploying a DWDM OTN backbone network, and the range of the Optical Signal Noise Ratio (OSNR) is between 20 dBm < OSNR < 40 dBm, which is the ideal value for OSNR, and has an Optical Rise Time Budget (ORTB) < 60 ps, and also has a segment margin system of > 7 dB.

Optical Cable Backbone Network Design In The Province Kalimantan Middle Use Technology DWDM OTN

In designing the backbone network for the province of East Kalimantan using Dense Wavelength Division Multiplexing (DWDM) and Optical Transport Network (OTN) devices which cover 10 districts and cities consisting of 34 segments, of which 34 segments consist of 10 OTN DWDM sites and 16 Optical Land Amplifier sites ( OLA). From the results of the design and simulation of the backbone network, it was found that the value of the Optical Link Power Budget (OLPB) < 50 dBm where this value is the ideal value in deploying a DWDM OTN backbone network, and the range of the Optical Signal Noise Ratio (OSNR) is between 20 dBm < OSNR < 40 dBm, which is the ideal value for OSNR, and has an Optical Rise Time Budget (ORTB) < 60 ps, and also has a segment margin system of > 7 dB.

Optical Cable Backbone Network Design In The Province Kalimantan South Use Technology DWDM OTN

In designing the backbone network for the province of East Kalimantan using Dense Wavelength Division Multiplexing (DWDM) and Optical Transport Network (OTN) devices which cover 10 districts and cities consisting of 34 segments, of which 34 segments consist of 10 OTN DWDM sites and 16 Optical Land Amplifier sites ( OLA). From the results of the design and simulation of the backbone network, it was found that the value of the Optical Link Power Budget (OLPB) < 50 dBm where this value is the ideal value in deploying a DWDM OTN backbone network, and the range of the Optical Signal Noise Ratio (OSNR) is between 20 dBm < OSNR < 40 dBm, which is the ideal value for OSNR, and has an Optical Rise Time Budget (ORTB) < 60 ps, and also has a segment margin system of > 7 dB.

Optical Cable Backbone Network Design In The Province Kalimantan North Use Technology DWDM OTN

In designing the backbone network for the province of East Kalimantan using Dense Wavelength Division Multiplexing (DWDM) and Optical Transport Network (OTN) devices which cover 10 districts and cities consisting of 34 segments, of which 34 segments consist of 10 OTN DWDM sites and 16 Optical Land Amplifier sites ( OLA). From the results of the design and simulation of the backbone network, it was found that the value of the Optical Link Power Budget (OLPB) < 50 dBm where this value is the ideal value in deploying a DWDM OTN backbone network, and the range of the Optical Signal Noise Ratio (OSNR) is between 20 dBm < OSNR < 40 dBm, which is the ideal value for OSNR, and has an Optical Rise Time Budget (ORTB) < 60 ps, and also has a segment margin system of > 7 dB.

Joint Symbol Rate-Modulation Format Identification and OSNR Estimation Using Random Forest Based Ensemble Learning for Intermediate Nodes

In this paper, a novel joint symbol rate-modulation format identification (SR-MFI) and optical signal-to-noise ratio (OSNR) estimation scheme using the low-bandwidth coherent detecting and random forest (RF)-based ensemble learning is proposed for intermediate nodes in the flexible dense wavelength division multiplexing (F-DWDM) networks. By leveraging low-bandwidth coherent detecting with small bulk wavelength scanning, no chromatic dispersion compensation and low-complexity RF, the proposed scheme could serve as a reduced-complexity and cost-effective option to realize joint SR-MFI and OSNR estimation at intermediate nodes in F-DWDM networks. To verify the feasibility of the proposed scheme, the comprehensive simulations of 8/16 GBaud polarization division multiplexing (PDM)-4/16/32/64 quadrature amplitude modulation (QAM) systems are conducted. The simulation results show that the identification accuracy of SR-MFI reaches 100% and the mean absolute error of OSNR estimation is within 1 dB. Moreover, the proposed monitoring scheme is verified by 8/16 GBaud PDM-4/16/32QAM coherent transmission experiments.

Learning to Classify DWDM Optical Channels from Tiny and Imbalanced Data.

Applying machine learning algorithms for assessing the transmission quality in optical networks is associated with substantial challenges. Datasets that could provide training instances tend to be small and heavily imbalanced. This requires applying imbalanced compensation techniques when using binary classification algorithms, but it also makes one-class classification, learning only from instances of the majority class, a noteworthy alternative. This work examines the utility of both these approaches using a real dataset from a Dense Wavelength Division Multiplexing network operator, gathered through the network control plane. The dataset is indeed of a very small size and contains very few examples of “bad” paths that do not deliver the required level of transmission quality. Two binary classification algorithms, random forest and extreme gradient boosting, are used in combination with two imbalance handling methods, instance weighting and synthetic minority class instance generation. Their predictive performance is compared with that of four one-class classification algorithms: One-class SVM, one-class naive Bayes classifier, isolation forest, and maximum entropy modeling. The one-class approach turns out to be clearly superior, particularly with respect to the level of classification precision, making it possible to obtain more practically useful models.

Design and control of highly spectrally efficient photonic networks enabled by fiber-granular routing on overlaid ring-shaped topologies

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 add/drop operations. The spectrum narrowing induced by node operations is well controlled by the impairment-suppressing routing and wavelength assignment (RWA) method. Numerical simulations on several metro-scale network topologies verify that the proposal enhances the spectral efficiency by up to 31.0% compared to comparable dense WDM networks.

Spectral processing techniques for efficient monitoring in optical networks

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). However, omnipresent OSAs represent an infeasible solution. Nevertheless, the advent of new, relatively cheap, compact and medium-resolution optical channel monitors (OCMs) enable a more intensive deployment of these devices. In this paper, we identify two main scenarios for the placement of such monitors: at the ingress and at the egress of the optical nodes. In the ingress scenario, we can directly estimate the parameters related to the signals, but not those related to the filters. On the contrary, in the egress scenario, the filter-related parameters can be easily detected, but not those related to amplified spontaneous emission. Therefore, we present two methods that, leveraging a curve fitting and a machine learning regression algorithm, allow detection of the missing parameters. We verify the proposed solutions with spectral data acquired in simulation and experimental setups. We obtained good estimation accuracy for both setups and for both studied placement scenarios. It is noteworthy that in the experimental assessment of the ingress scenario, we achieved a maximum absolute error (MAE) lower than 1 GHz in filter bandwidth estimation and a MAE lower than 0.5 GHz in filter frequency shift estimation. In addition, by comparing the relative errors of the considered parameters, we identified the ingress scenario as the more beneficial. In particular, we estimated the filter central frequency shift with 84% and the filter 6 dB bandwidth with 75% higher accuracy, with respect to datasheet/reference values. This translates into a total reduction of the estimated signal-to-noise ratio (SNR) penalty, introduced by a single optical filter, of 0.24 dB.

Performance of subcarrier-wave quantum key distribution in the presence of spontaneous Raman scattering noise generated by classical DWDM channels

In this paper, we study the performance of the subcarrier-wave quantum key distribution system (SCW QKD) in the presence of spontaneous Raman scattering (SpRS) noise generated by classical channels of the dense wavelength division multiplexing (DWDM) network within a single-mode optical fiber. We present the mathematical model for evaluation of the quantum bit error rate and secure key generation rate with the SpRS noise taken into account. We consider two regimes of the SCW QKD system: the continuous wave regime, which uses a continuous wave laser, and the pulsed regime. For these regimes, performance of the system is analyzed depending on receiver sensitivity of classical DWDM. It is found that the pulsed regime outperforms the continuous wave regime in both the secure key generation rate and maximum achievable distance.

Study of POST and PRE-Scheme of Dispersion Compensation in a 32 Channel DWDM Network with NRZ, RZ and Encoded Transmitter

Dense Wavelength Division Multiplexing (DWDM)is a technique that has been developed to improve the channel range and bandwidth of optical fibre transmission systems. Multiple information channels of varying wavelengths are sent on a single fibre The phenomenon of an input signal spreading out as it flows down the fibre is referred to as optical fibre dispersion. Chromatic, modal and polarisation mode dispersion are all examples of dispersion in fibre optic cable. To compensate for such dispersion, this paper introduces two techniques: Dispersion Compensation Fibre (DCF) and fibre Bragg Grating (FBG).In this paper we will explore Pre, Post Dispersion compensation technique with input as RZ, NRZ and MDRZ encoded. This analysis was carried out and simulated using Optisystem17, which took into account a number of variables such as Maximum Quality Factor, Eye Height, and Minimum Bit Error Rate (BER). Results were analysed for different lengths of transmission.

Optical Cable Backbone Network Design in West Kalimantan Province Using OTN DWDM Technology

In designing the backbone network for the province of West Kalimantan using Dense Wavelength Division Multiplexing (DWDM) and Optical Transport Network (OTN) devices which cover 14 districts and cities consisting of 30 segments, of which 30 segments consist of 14 DWDM OTN sites and 8 Optical Land Amplifier sites ( OLA). From the results of the design and simulation of the backbone network, it was found that the value of the Optical Link Power Budget (OLPB) < 50 dBm where this value is the ideal value in deploying a DWDM OTN backbone network, and the range of the Optical Signal Noise Ratio (OSNR) is between 20 dBm < OSNR < 40 dBm, which is the ideal value for OSNR, and has an Optical Rise Time Budget (ORTB) < 60 ps, and also has a segment margin system of > 7 dB.

Heuristic planning algorithm for sharing restoration interfaces in OTN over DWDM networks

Due to the expansion of telecommunication services, the demand for technologies that improve transmission quality has been growing in recent years. One of these technologies is optical transport networks (OTNs), which works as a layer above the DWDM (Dense Wavelength Division Multiplexing) network to enable the most efficient use of resources. This work proposes an OTN network planning solution over DWDM based on heuristic algorithms. The main objective is to plan the allocation of OTN network interfaces (the most costly element) to meet the performance and resilience requirements. We implemented two versions of the heuristic algorithm. The first version, called OTN-PASRIN-Max, delivers a robust solution to ensure all planning requirements, but the heuristic does not guarantee a solution that deploys the minimum number of resources. The second version, which is our main proposal, is called OTN-PASRIN and returns a solution that simultaneously maximizes resilience and minimizes the deployment of resources through better reuse of components, which causes a reduction in the final cost of the project. We evaluate our proposal in two scenarios, a small network with 4 OTN nodes, and a larger network with 16 OTN nodes. For the small network, we compared the results of the proposed algorithm with an exhaustive search, and the results were very close in all traffic conditions. In the larger network, we performed a comparison between our proposal and the other version (OTN-PASRIN-Max). The results showed that OTN-PASRIN saves a considerable amount of resources (approximately 20%) in all studied scenarios.

Comparative Simulation Analysis of Dispersion Mitigation Techniques Using Symmetrical-DCF, FBG and CFBG in High Speed DWDM Networks

The performance of the dense wavelength division multiplexing (DWDM) network is severely limited by the chromatic dispersion. So, it is crucial to mitigate and compensate this dispersion. In this paper, the different dispersion compensation techniques are discussed and compared. The DWDM system performance is evaluated by utilizing these dispersion mitigation techniques. The techniques used are dispersion compensation fiber (DCF) with symmetrical compensation scheme, Fiber Bragg Grating (FBG) and Chirped Fiber Bragg Grating (CFBG). The system performance is investigated for 16-channels DWDM network using Return-to-Zero (RZ) and Non-Return-to-Zero (NRZ) modulation formats over transmission distance up to 200 km at 2.5 and 5 Gb/s data flow rate per channel. The system performance is evaluated according to Quality factor (Q-factor), Optical Signal to Noise Ratio (OSNR) and Signal to Noise Ratio (SNR) through Eye Diagrams. The DWDM network is implemented by using Optisystem simulator. The simulation results are outlined in tables indicating the most efficient dispersion compensation technique. The simulation results revealed that the systems using FBG as dispersion compensator offers better performance and larger Q-factor especially for longer transmission distance. FBG achieved Q-factor of approximately 38 and 62 which are the larger Q-factor values compared to other dispersion compensation methods at data rate of 2.5 Gb/s over 200 km fiber length for NRZ and RZ respectively. Furthermore, as data rate increases, the performance is reduced adversely due to pulse broadening causing interference with adjacent channels. Finally, the systems using RZ format provides better performance than those that using NRZ although, NRZ has less pulse broadening due to its reduced bandwidth.

Demonstration of Stealthy and Encrypted Optical Transmission Below Adjacent 50 GHz DWDM Channels

A stealthy and encrypted transmission is demonstrated in a dense-WDM network. The residual gap between two neighboring commercial channels is utilized for the transmission of the secured channel, hidden below the amplifier noise at negative -10 dB/0.1nm OSNR. The stealthy and encrypted channel is generated by a digital replication of the baseband signal together with a digital spectral phase mask. This technique provides encryption and steganography as it exclusively allows the eligible user to obtain a considerable processing-gain, and to recover extremely low OSNR signals. In this work the secured channel is explored under stringent network conditions. A stealth transmission was tested between two high OSNR public channels, separated 50 GHz apart: Unshaped 25 Gbps NRZ channel and digitally shaped coherent PM-QPSK 112 Gbps channel. Although it is significantly overlapped by adjacent channels and covered by the ASE noise, we demonstrate error-free detection of the secured channel, without significant effect on the commercial channels.

HUBBLE: an optical link management system for dense wavelength divisionmultiplexing networks

Timely detection of Dense Wavelength Division Multiplexing (DWDM) link quality and service performance problems of fiber deployment are important and critical for telecommunication operators. In this paper, we propose a new methodology for network fault detection inside optical transmission systems deployed in a real-operator environment and present the working principles of the system. Our new calculation methodology is used for joint fiber and DWDM link quality evaluation inside the proposed High-level Unified BackBone Link Examiner (HUBBLE) platform. At the end of the paper, we also detail some of the benefits, challenges, and opportunities of automation in DWDM networks using the proposed HUBBLE platform