- Joaquim Ferreira Martins-Filho was born in Recife, Brazil. He received the B.Sc. degree in Electronics Engineering fr... moreJoaquim Ferreira Martins-Filho was born in Recife, Brazil. He received the B.Sc. degree in Electronics Engineering from the Federal University of Pernambuco (UFPE), in Recife, in 1989, and the M.Sc. degree in Physics from the same institution in 1991. He received his Ph.D. degree in Electronics Engineering from the University of Glasgow, Scotland, in 1995. In 1998 he joined the Photonics Group, Department of Electronics and Systems of UFPE, in Recife, where he was the graduate program coordinator, was the head of department, and currently is a full professor. His research interests are in devices, subsystems, transmission systems and networking for optical communications, and optical sensors. He has coordinated several research projects financed by state and federal agencies as well as by industries. He published over 200 full papers in journals and conferences and advised over 30 postdoc, Ph.D. and M.Sc. students. Prof. Joaquim Martins-Filho is a Senior Member of the IEEE (Institute of Electrical and Electronics Engineers), Senior Member of OSA (Optical Society), Member of SBMO (Brazilian Microwave and Optoelectronics Society), Member of SBFOTON (Brazilian Photonics and Optics Society) and SBrT (Brazilian Telecommunication Society), as well as a Research Fellow (PQ-1C) of the National Research Council of Brazil (CNPq). He was the coordinator of the CNPq Committee for Electrical Engineering. He currently is the Research Director of UFPE.(Joaquim Ferreira Martins-Filho was born in Recife, Brazil. He received the B.Sc. degree in Electronics Engineering from the Federal University of Pernambuco (UFPE), in Recife, in 1989, and the M.Sc. degree in Physics from the same institution in 1991. He received his Ph.D. degree in Electronics Engineering from the University of Glasgow, Scotland, in 1995. In 1998 he joined the Photonics Group, Department of Electronics and Systems of UFPE, in Recife, where he was the graduate program coordinator, was the head of department, and currently is a full professor. His research interests are in devices, subsystems, transmission systems and networking for optical communications, and optical sensors. He has coordinated several research projects financed by state and federal agencies as well as by industries. He published over 200 full papers in journals and conferences and advised over 30 postdoc, Ph.D. and M.Sc. students. Prof. Joaquim Martins-Filho is a Senior Member of the IEEE (Institute of Electrical and Electronics Engineers), Senior Member of OSA (Optical Society), Member of SBMO (Brazilian Microwave and Optoelectronics Society), Member of SBFOTON (Brazilian Photonics and Optics Society) and SBrT (Brazilian Telecommunication Society), as well as a Research Fellow (PQ-1C) of the National Research Council of Brazil (CNPq). He was the coordinator of the CNPq Committee for Electrical Engineering. He currently is the Research Director of UFPE.)edit
We present for the first time results of soliton transmission in the S-band. We performed computer simulations of single channel solitonic communication systems at 80 Gbit/s and 160 Gbit/s, in the Quasi-Adiabatic regime, in the S and C... more
We present for the first time results of soliton transmission in the S-band. We performed computer simulations of single channel solitonic communication systems at 80 Gbit/s and 160 Gbit/s, in the Quasi-Adiabatic regime, in the S and C bands. For the S band we employ non-zero dispersion shifted fibers (NZDSF) and thulium doped fiber amplifiers (TDFA) in the optical communication
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Page 1. Noise Figure Model for Transmission Performance Evaluation Considering Four Wave Mixing and Source Spontaneous Emission Carmelo JA Bastos-Filho, and Joaquim F. Martins-Filho Grupo de Fotônica, Departamento ...
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Recent studies demonstrated the advantage of alternative methods to assess optical networks based on Artificial Neural Networks (ANN), which is to obtain a fast estimation of Blocking Probability (BP) with a small error. In previous works... more
Recent studies demonstrated the advantage of alternative methods to assess optical networks based on Artificial Neural Networks (ANN), which is to obtain a fast estimation of Blocking Probability (BP) with a small error. In previous works we proposed the use of ANNs to predict the BP of optical networks with dynamic traffic by using topological metrics and general information of the physical layer. In this paper we use the node locations of six deployed networks in order to evaluate the robustness of the estimator. We also propose four new measures related to physical layer and we compare the results of our proposal with the outcome of a discrete event network simulator. From our results we conclude that ANN is a promising technique to estimate the BP of transparent optical networks because we obtained a fast BP estimation with small errors for all analyzed networks.
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Some characteristics of optical networks can be assessed by analyzing the topology of the network. Many metrics can be used for this purpose. Modularity indicators were already proposed to study complex networks, and they have been useful... more
Some characteristics of optical networks can be assessed by analyzing the topology of the network. Many metrics can be used for this purpose. Modularity indicators were already proposed to study complex networks, and they have been useful to clarify many real world problems. In this paper, we propose an indicator inspired in the traditional modularity concept aiming at finding suitable routes in optical networks. The primary goal of this study is to introduce a measure of the degree of interference between routes to be used in the routing process in order to improve the overall performance of optical networks. We provide some preliminary results, which show that our proposal is promising.
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Page 1. Influence of Pump Direction in All-Optical Gain-Clamped Erbium Doped Fiber Amplifier Carmelo JA Bastos-Filho, Marcela Martins Melo, and Joaquim F. Martins-Filho Grupo de Fotônica, Departamento de Eletrônica ...
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ABSTRACT The assessment of optical networks considering physical impairments is frequently accomplished by using time consuming analysis tools. We propose in this paper to use Artificial Neural Networks to predict the Blocking Probability... more
ABSTRACT The assessment of optical networks considering physical impairments is frequently accomplished by using time consuming analysis tools. We propose in this paper to use Artificial Neural Networks to predict the Blocking Probability of Optical Networks with Dynamic Traffic by using topological metrics and general information of the physical layer. The training process is accomplished by supervised learning based on a historical database of networks. We also propose a new and simple topological property to represent the capacity of the network to distribute traffic. From the results, we found that this novel topological property improves the estimator accuracy. We compared the results of our proposal with the outcome of a discrete event simulator for optical networks. The simulator provides an estimate for blocking probability of all-optical networks considering physical impairments. We show that our approach is faster than discrete event simulators, we obtained a speedup higher than 7,500 times, with comparable estimation errors.
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Recent studies demonstrated the feasibility of surrogate methods to assess optical networks based on Artificial Neural Networks (ANNs). However, surrogate methods present different trade offs between accuracy and resource utilization... more
Recent studies demonstrated the feasibility of surrogate methods to assess optical networks based on Artificial Neural Networks (ANNs). However, surrogate methods present different trade offs between accuracy and resource utilization efficiency, such as computational time. In this paper we analyze the use of ANN to forecast the Blocking Probability (BP) of deployed optical networks considering different architectures for the underlying alternative method. We also analyze the impact of the adopted physical layer model and the number of optical networks needed to train the ANN. We compare the results of our proposal with the outcome of a discrete event network simulator. From our results we can conclude that ANN is a promising technique to estimate the BP of transparent optical networks, but the dataset used to train the ANN and the physical layer model are crucial for the proper design of this type of tool.
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Graphs can be used to model many real-world problems, such as social networks, telecommunication networks and biological structures. To aid the analysis of complex networks, several topological metrics and generational procedures have... more
Graphs can be used to model many real-world problems, such as social networks, telecommunication networks and biological structures. To aid the analysis of complex networks, several topological metrics and generational procedures have been proposed in the last years. This work offers a systematic method to analyse different backbone optical networks, based on a non-supervised algorithm for clustering and investigates the power of a recently proposed topological metrics, named \({I({\hat{\mathcal {F}}})}\). The metrics \({I({\hat{\mathcal {F}}})}\) and three others are applied to identify the best canonical model to represent real backbone optical networks. According to the obtained results, the clustering procedure allows to indicate \({I({\hat{\mathcal {F}}})}\) as the better metrics to explain the installed capacity for the analysed networks.
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The assessment of networks is frequently accomplished by using time-consuming analysis tools based on simulations. For example, the blocking probability of networks can be estimated by Monte Carlo simulations and the network resilience... more
The assessment of networks is frequently accomplished by using time-consuming analysis tools based on simulations. For example, the blocking probability of networks can be estimated by Monte Carlo simulations and the network resilience can be assessed by link or node failure simulations. We propose in this paper to use Artificial Neural Networks (ANN) to predict the robustness of networks based on simple topological metrics to avoid time-consuming failure simulations. We accomplish the training process using supervised learning based on a historical database of networks. We compare the results of our proposal with the outcome provided by targeted and random failures simulations. We show that our approach is faster than failure simulators and the ANN can mimic the same robustness evaluation provide by these simulators. We obtained an average speedup of 300 times.
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In this paper, we propose a new approach to handle the design of optical networks in scenarios related to the discovery of the most suitable node locations. In general, the node locations of backbone networks are previously defined, and... more
In this paper, we propose a new approach to handle the design of optical networks in scenarios related to the discovery of the most suitable node locations. In general, the node locations of backbone networks are previously defined, and they are posed as input for optimization algorithms. However, different node locations can offer better tradeoffs regarding capital expenditure and network performance. According to our knowledge, this is the first study to propose node locations as decision variables in network optimization together with the physical topology design process. We offer an approach based on clustering to select suitable group of node locations and a many objective memetic evolutionary algorithm that performs a local search to find better node locations during the optimization process. According to our results, our approach presented better than the previous proposals concerning hypervolume and can be pointed as a new way to modeling network planning tools, especially f...
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Some important metrics to measure the transmission quality of the signal in optical links are OSNR Ripple and Tilt. They have a relevant impact on the transmission quality of an optical signal in links with a cascade of amplifiers. This... more
Some important metrics to measure the transmission quality of the signal in optical links are OSNR Ripple and Tilt. They have a relevant impact on the transmission quality of an optical signal in links with a cascade of amplifiers. This paper compares the OSNR Ripple and Tilt between the MOO and PSO adaptive control of operating point (ACOP) approaches in links with a cascade of amplifiers. The results show that both techniques have a similar performance for up to 7 amplifiers with mean values below 0.5 dB and 0.85 dB for OSNR Ripple and Tilt, respectively. In scenarios with eight amplifiers, the PSO performed worse, with mean OSNR Ripple and Tilt values exceeding 2 dB in the same scenarios.
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This work presents the computational modeling of a fiber-based corrosion sensor with two different metalized regions, on the side-polished D-shaped fiber and on the end cleaved fiber, providing an improved sensor detection range. The... more
This work presents the computational modeling of a fiber-based corrosion sensor with two different metalized regions, on the side-polished D-shaped fiber and on the end cleaved fiber, providing an improved sensor detection range. The sensor structure is numerically modeled with COMSOL Multiphysics. Results evidenced the existence of two corrosion detection ranges capable of providing the corrosion rate independently, and in a wider range of film thickness. Moreover, we present a comparison of the sensor characteristics for two different metals used in the thin film of the transducing element, indicating superior performance of nickel compared to aluminum.
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... Several pumping schemes for thulium doped fiber amplifiers (TDFA) have been reported, including single-wavelength up-con version pumping and also dual wavelength pumping [1-3 J. Single wavelength direct pumping near 800nm in Tm-doped... more
... Several pumping schemes for thulium doped fiber amplifiers (TDFA) have been reported, including single-wavelength up-con version pumping and also dual wavelength pumping [1-3 J. Single wavelength direct pumping near 800nm in Tm-doped fibers is very inefficient due to ...
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Dynamic operation is one of the current challenges in optical communication and networks, and the adaptive control of optical amplifier (ACOP) is one of the problems in this challenge. The ACOP approaches aim to define the gains of the... more
Dynamic operation is one of the current challenges in optical communication and networks, and the adaptive control of optical amplifier (ACOP) is one of the problems in this challenge. The ACOP approaches aim to define the gains of the optical amplifiers dynamically to increase the quality of the transmission after a cascade of amplifiers. The most recent ACOP approach uses a multiobjective evolutionary optimization algorithm to define the gains of the amplifiers to maximize the optical signal to noise ratio (OSNR) and to minimize OSNR ripple. Despite the promising results regarding Quality of Transmission, it is not desirable to rely on an evolutionary algorithm to make decisions in real-time. In this work, we investigate the creation of a surrogate model that can obtain solutions as good as the multiobjective algorithm, but in real-time. We show the results for a machine learning (ML) regression technique, trained with the optimization algorithm solutions, can return configurations with OSNR less than 1 dB close to the best OSNR returned by the optimization algorithm. Moreover, the ML solution answers in milliseconds, whereas the optimization-based approach needs several minutes to find a proper configuration.
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The definition of the operating point for an optical amplifier is a problem that needs to deal with the characteristics of the amplifier and to return a solution that reaches the best quality of transmission (QoT) for the involved optical... more
The definition of the operating point for an optical amplifier is a problem that needs to deal with the characteristics of the amplifier and to return a solution that reaches the best quality of transmission (QoT) for the involved optical link. The definition of the gain needs to be performed autonomously, especially in dynamic optical networks. This problem is called the adaptive control of optical amplifiers operating point (ACOP). One of the most recent ACOP proposal showed that the inclusion of a variable optical attenuator (VOA) in the amplifier output can help to achieve solutions that minimize both the linear and nonlinear interferences in the optical signal. This approach uses a multi-objective optimization algorithm that defines the amplifier gains and VOA losses aiming to maximize the minimum optical signal-to-noise ratio (OSNR) and minimize the OSNR ripple. Nevertheless, another essential aspect for the QoT in the optical system is the signal power tilt, and this metric was not considered in any of the previous ACOP approaches. Therefore, in this work, we analyze the solutions returned by the most recent ACOP approaches to investigate the performance of these solutions concerning the signal power tilt. The obtained results show that solutions with high OSNR and low OSNR ripple can have high power tilt, which indicates that this last metric should be considered in the ACOP approaches.
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In this paper we investigate the impact of the fiber types arrangement on the performance of bidirectional mixed-fiber optical links. It is shown how to compose an optical link given a set of different fiber types in order to optimize the... more
In this paper we investigate the impact of the fiber types arrangement on the performance of bidirectional mixed-fiber optical links. It is shown how to compose an optical link given a set of different fiber types in order to optimize the transmission bit error rate (BER). To this aim, a nonlinear interference noise (NLIN) theoretical prediction model was adapted to take into account different fiber types and their positions in the optical link. The analysis was performed considering a coherent wavelength-division multiplexing (WDM) transmission system with no inline dispersion compensation.
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Optical networks are currently the only technology capable of providing extremely high data transmission rates. Because of this, systems must be increasingly efficient and immune to failures. One of the ways to improve network efficiency... more
Optical networks are currently the only technology capable of providing extremely high data transmission rates. Because of this, systems must be increasingly efficient and immune to failures. One of the ways to improve network efficiency is to use dynamic systems. One of the solutions is the use of ACOP (Adaptive Control of Operating Point) techniques, which consists of autonomously choosing the best operating point for optical amplifiers on the link, thus providing the best configuration in terms of QoT (Quality of transmission). Unlike the previous works that focused on optimizing QoT and OSNR (Optical Signal-To-Noise Ratio), our proposal is focused on maximizing the transmission rate. In this paper, we deploy a global optimizer, called Particle Swarm Optimization, to solve the ACOP problem and choose the best configuration for an optical link concerning the transmission rate. We showed that our proposal outperforms the previous ACOP approaches found in the literature for a set of link scenarios concerning the transmission rate.
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Elastic Optical Networks (EON) have been a constant focus of studies in recent years because they have characteristics that stand out in relation to current optical networks. Among these characteristics, it is possible to highlight the... more
Elastic Optical Networks (EON) have been a constant focus of studies in recent years because they have characteristics that stand out in relation to current optical networks. Among these characteristics, it is possible to highlight the ability to transmit data with different bandwidths, adapted to the demand, which guarantees a high spectral efficiency. Different techniques and heuristics have been presented in order to solve the Routing and Spectrum Allocation (RSA) problem, which emphasize in providing efficient solutions for the packaging of requests within the optical spectrum. In this article, it is proposed the adaptation of an efficient spectrum assignment heuristic, referred to as Min Slot-Continuity Capacity Loss (MSCL), with the Split Spectrum technique. It is shown that by combining different forms of spectrum division with the spectrum assignment that generates the least loss of capacity, an efficient technique may be applied to EONs that provides better results than either the traditional algorithms of spectrum allocation (FF and MSCL) and the classic form of spectrum division.
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In this paper, we propose a new approach to estimate the gain and the noise figure of EDFAs. This is an important tool for solving the adaptive control of operating point (ACOP) problem in optical amplifiers. The proposal uses an... more
In this paper, we propose a new approach to estimate the gain and the noise figure of EDFAs. This is an important tool for solving the adaptive control of operating point (ACOP) problem in optical amplifiers. The proposal uses an artificial neural network to enable a quick estimation of both amplifiers features requiring a small amount of memory. Results show that the neural network estimator is 80 times faster and uses 804 times fewer data than state of the art estimator, without losing significant accuracy. These advantages will help the use of iterative optimization techniques, like computational intelligence, to tackle the ACOP problem. Besides, it can assist in the implementation of ACOP approaches in simple devices like microcontrollers.
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In this article we present a software to simulate Transparent Optical Networks (SIMTON). SIMTON is an eventdriven simulation software implemented in C++ which takes into account optical device characteristics for the evaluation of network... more
In this article we present a software to simulate Transparent Optical Networks (SIMTON). SIMTON is an eventdriven simulation software implemented in C++ which takes into account optical device characteristics for the evaluation of network blocking probability in wavelength routed transparent optical networks. The simulator uses a physical layer model that considers the following effects: device losses, fiber attenuation, four wave mixing, residual chromatic dispersion and polarization mode dispersion in optical fibers, gain saturation in optical amplifiers (Erbium Doped Fiber Amplifier), dependence of the amplified spontaneous emission noise with the input power in EDFA, in-band crosstalk in optical switches, and source spontaneous emission noise of the laser transmitter. By using SIMTON it is possible to adjust the parameters of the optical devices, as well as to choose the routing and wavelength assignment algorithm. Moreover, the tool has a graphical interface. We also present some examples of network analysis results obtained from SIMTON.
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In optical communication systems, optical amplifiers play a fundamental role. Due to the current challenge to adapt the optical network to be more dynamic, it is necessary to adapt the optical amplifiers so that their operation is... more
In optical communication systems, optical amplifiers play a fundamental role. Due to the current challenge to adapt the optical network to be more dynamic, it is necessary to adapt the optical amplifiers so that their operation is autonomous and favors transmission quality. Thus, the ACOP (Adaptive Control of Operating Point) problem arises, whose objective is to adapt the amplifier configuration according to the state of the network. In the solutions in the literature, it is essential to have a set of amplifier operating points, called the power mask. There are techniques capable of estimating the amplifier’s behavior at points not defined in the power mask. However, few of them consider non-flat input signal power spectrum, which is common in real-world scenarios. This work proposes adapting a previous optical signal estimation technique to consider power masks created with non-flat signals. The results show that this inclusion improved the performance of the original technique. For example, considering the median of the maximum error, the reduction was from around 4 dB (original technique) to around 0.2 dB (proposed adaptation). Furthermore, the adaptation obtained similar results to another technique in the literature that considers non-flat signals and is based on artificial neural networks.
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Optical networks are currently the only technology capable of providing extremely high data transmission rates. Because of this, systems must be increasingly efficient and immune to failures. One way to improve network efficiency is to... more
Optical networks are currently the only technology capable of providing extremely high data transmission rates. Because of this, systems must be increasingly efficient and immune to failures. One way to improve network efficiency is to use dynamic approaches like Adaptive Control of Operating Point, which consists of autonomously choosing the best operating point for optical amplifiers on the link, thus providing the best configuration concerning Quality of transmission. Unlike the previous works that focused on optimizing Optical Signal-To-Noise Ratio, our proposal and analysis are focused on maximizing the transmission rate. In this paper, we compare the results obtained by five different and widely used evolutionary and swarm-based algorithms in the search for maximizing the transmission rate in optical links. We have observed that the differential evolution provided the best results in the analyzed scenarios.
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This work presents the fabrication and characterization of a D-shaped plastic optical fiber based refractive index sensor. It is used in sensing the refractive index of different liquids and solutions with glycerin. The sensor fabrication... more
This work presents the fabrication and characterization of a D-shaped plastic optical fiber based refractive index sensor. It is used in sensing the refractive index of different liquids and solutions with glycerin. The sensor fabrication process is based on the side polishing of a plastic optical fiber to build the structure known as the D-shaped section. The performed measurements allowed the characterization of the sensor sensitivity and resolution, and they indicate the device has potential application as a concentration sensor in liquid mixtures or as a contaminant detector.
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In all-optical networks, signals are transmitted through optical physical layer with no regeneration. Therefore, noise accumulation along lightpath can severely impair optical signal-to-noise ratio. Impairment aware routing and wavelength... more
In all-optical networks, signals are transmitted through optical physical layer with no regeneration. Therefore, noise accumulation along lightpath can severely impair optical signal-to-noise ratio. Impairment aware routing and wavelength assignment algorithms (IA-RWA) can take into account these effects, improving the network performance. In this paper we describe a fast and high performance adaptive weight function to be used as the metric for the routing algorithm in optical networks constrained by physical impairments. The input information for this function are link availability, route length and two adjustable parameters. These two parameters provide information about the network impairments. An offline simulation must be run to adjust them prior to the online network operation. The main advantage of this approach is the use of simple network parameters during the routing process instead of a complex optical noise based formulation, which renders it a better performance in terms of both, time to find a route and blocking probability. In our simulations we considered three physical layer effects: ASE noise generation, Optical Amplifier gain and ASE saturation and OXC crosstalk. We performed a performance comparison between this new metric and other metrics previously described in the literature.
Elastic optical networks (EONs) have been pointed out as a promising candidate for transporting data with high transmission rates in adaptive optical networks. Consequently, the occurrence of a failure in a simple element may cause the... more
Elastic optical networks (EONs) have been pointed out as a promising candidate for transporting data with high transmission rates in adaptive optical networks. Consequently, the occurrence of a failure in a simple element may cause the interruption of various services. Survival mechanisms have been crucial to try to overcome the problems created by possible failures. In this paper, we propose a new dedicated path protection mechanism for link-failure survivability in EONs, referred to as Spectrum Continuity and Contiguity based Dedicated Protection (SCCDP). SCCDP tries to avoid the trap topology problem in search for a link-disjoint route pair. In addition, the calculation of the link-disjoint routes is based on modified version of the Dijkstra's algorithm, referred to as Spectrum Continuity and Contiguity based Shortest Path (SCCSP), which chooses the pair of routes according to the end-to-end spectrum continuity and contiguity. The performance of the proposed algorithm is compared to other well-known algorithms in the Literature. Two different network topologies are used in our simulations for comparison purposes. Our proposal achieved better results concerning blocking probability.
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WDM optical networks allow the transmis- sion of multiple services with high rates and low cost. Therefore, the occurrence of a failure in any network element can cause loss of several services. Some sur- vival mechanisms may be used to... more
WDM optical networks allow the transmis- sion of multiple services with high rates and low cost. Therefore, the occurrence of a failure in any network element can cause loss of several services. Some sur- vival mechanisms may be used to try to overcome this type of failure event. We present in this paper a new dedicated protection algorithm for link-failure surviv- ability in WDM optical networks, referred to as Power Series based Dedicated Protection (PSDP) Algorithm. PSDP is based on the evaluation of the network links’ costs by using a power series expansion. This power se- ries expansion uses input variables based on some rel- evant information of the network such as link physical length and wavelength availability. Other contribution of this paper is to propose a new input variable based on the wavelength continuity constraint. The performance of the proposed algorithm is compared to other well known algorithms in the literature. We also propose a modification in Suurballe’s algorithm and compare it with our PSDP algorithm. Three different topologies are used in our simulations and statistical analysis is performed on the results of the investigated algorithms. In all simulated cases, PSDP algorithm outperformed the other analyzed algorithms.
We propose two policies to select the route for an adaptive-alternative routing algorithm for all-optical networks. We use the NrPSR to find the Nr routes with lower cost for a given source-destination pair according to a cost function... more
We propose two policies to select the route for an adaptive-alternative routing algorithm for all-optical networks. We use the NrPSR to find the Nr routes with lower cost for a given source-destination pair according to a cost function expanded in a power series (PSR) in which the coefficients are determined by a Particle Swarm Optimizer (PSO). The selected route to attend to the call request can be chosen among the Nr found routes depending on the adopted policy. In the first proposal, named NrPSR(OSNRJE), we select the route that presents the lower OSNR that attends the Quality of Transmission requirements. In the second approach, named NrPSR(OSNRMAX), we select the route that presents the higher OSNR. In our simulations we considered some physical layer effects, such as: ASE noise generation, Optical Amplifier gain and ASE saturation and OXC crosstalk. We compared the performance of our proposed policies to others previous proposed policies for the NrPSR and other well known algorithms described in the literature. NrPSR(OSNRJE) outperformed all other routing algorithms.
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To overcome the inefficiency of the rigid spectrum allocation in traditional wavelength division multiplexing (WDM) networks, a flexible grid networking paradigm for spectrum allocation has been recently proposed. On these Flexible-Grid... more
To overcome the inefficiency of the rigid spectrum allocation in traditional wavelength division multiplexing (WDM) networks, a flexible grid networking paradigm for spectrum allocation has been recently proposed. On these Flexible-Grid Optical Networks, the spectrum is not rigid, but flexible so that spectrum resources can be adaptively provided to client traffic demand. Spectrum allocation is performed by a process known in the literature as the Routing and Spectrum Assignment (RSA). The performance improvement imparted by RSA algorithms on currently proposed Flexible-Grid Optical Networks is a subject of current extensive investigation. In this paper, we propose a spectrum assignment algorithm based on First-Fit spectrum ordering, where slots are prioritized regarding to the number of forms how future variable-bandwidth path requests can be assigned. Case studies were carried out in order to analyze the benefits of the proposal. In the scenarios analyzed the proposed algorithm outperformed traditional First-Fit assignment.
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In this letter we extend the analysis of the Power Series Routing (PSR) algorithm, which was previously proposed and analyzed for transparent networks only, to the translucent and opaque networks. The PSR algorithm is a bio-inspired... more
In this letter we extend the analysis of the Power Series Routing (PSR) algorithm, which was previously proposed and analyzed for transparent networks only, to the translucent and opaque networks. The PSR algorithm is a bio-inspired impairment-aware routing algorithm that can be optimized and can adapt itself to the network conditions. We demonstrate that the PSR algorithm is also suitable for these network configurations. We compared the PSR algorithm with other well known routing algorithms and we observed that the PSR algorithm achieved the best performance in all cases.
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In this paper, we propose two strategies for sparse regenerator placement (RP) in translucent optical networks, named most used regenerator placement (MU-RP), and most simultaneous used regenerator placement (MSU-RP). Our proposals are... more
In this paper, we propose two strategies for sparse regenerator placement (RP) in translucent optical networks, named most used regenerator placement (MU-RP), and most simultaneous used regenerator placement (MSU-RP). Our proposals are compared to well known RP algorithms pre- sented in literature for two different network topologies for different network loads, distribution of load along the net- works and number of translucent nodes. MSU-RP presented remarkable results and outperformed all previous approaches in all cases, while MU-RP obtained a slightly superior or similar performance when compared to previous approaches presented in the literature.
As redes ópticas evoluíram nas últimas décadas permitindo a inclusão de funcionalidades de controle e gerenciamento no domínio óptico. Isso gerou um aumento na complexidade no projeto das redes ópticas, tornando interessante a utilização... more
As redes ópticas evoluíram nas últimas décadas permitindo a inclusão de funcionalidades de controle e gerenciamento no domínio óptico. Isso gerou um aumento na complexidade no projeto das redes ópticas, tornando interessante a utilização de técnicas de otimização evolucionárias capazes de lidar com múltiplos objetivos conflitantes em alta dimensiona- lidade no espaço de decisão. Este artigo apresenta uma breve revisão de recentes avanços, mostrando que é poss ível aperfeiçoar os operadores dos algoritmos evolucionários para que algumas das variaço ̃es destas técnicas de otimização evolucionárias, como o NSGA-II e o SPEA2, tornem-se mais adequadas para pro- jeto de redes ópticas. Também são apresentadas soluço ̃es para problemas conjuntos que geralmente são negligenciados, como projeto de topologia com definição de equipamentos e definição conjunta de colocação de regeneradores e definição do número de comprimentos de onda por enlace.
This article presents a new estrategy to assign wavelengths in a optical link considering the four wave mixing effect in the optical fiber. The four wave mixing effect in taken into account by using a formulation that calculates the fiber... more
This article presents a new estrategy to assign wavelengths in a optical link considering the four wave mixing effect in the optical fiber. The four wave mixing effect in taken into account by using a formulation that calculates the fiber noise figure for each wavelenght. We analyze the assignments when there are additions and droppings of wavelengths, considering the best and satisfactory assignments using the exhaustive and genetic algorithms, respectively. We obtain the distributions o wavelengthms from a genetic algorithm, which considers the quality of service criterion based on bit error rate. We show that our strategy is capable of determining assignments of wavelength, the maximum number of wavelengths and their positions in the grid to minimize the impact of the four wave mixing effect.
In this article we present a software to simulate Transparent Optical Networks (SIMTON). SIMTON is an eventdriven simulation software implemented in C++ which takes into account optical device characteristics for the evaluation of network... more
In this article we present a software to simulate Transparent Optical Networks (SIMTON). SIMTON is an eventdriven simulation software implemented in C++ which takes into account optical device characteristics for the evaluation of network blocking probability in wavelength routed transparent optical networks. The simulator uses a physical layer model that considers the following effects: device losses, fiber attenuation, four wave mixing, residual chromatic dispersion and polarization mode dispersion in optical fibers, gain saturation in optical amplifiers (Erbium Doped Fiber Amplifier), dependence of the amplified spontaneous emission noise with the input power in EDFA, in-band crosstalk in optical switches, and source spontaneous emission noise of the laser transmitter. By using SIMTON it is possible to adjust the parameters of the optical devices, as well as to choose the routing and wavelength assignment algorithm. Moreover, the tool has a graphical interface. We also present some examples of network analysis results obtained from SIMTON.
A novel method is presented to design the configuration of pumping lasers of Raman amplifiers using a multi-objective particle swarm optimizer. The goal is to obtain the pump laser wavelengths and powers that maximize the amplifier on-off... more
A novel method is presented to design the configuration of pumping lasers of Raman amplifiers using a multi-objective particle swarm optimizer. The goal is to obtain the pump laser wavelengths and powers that maximize the amplifier on-off gain, while maintaining the flatness of the gain over the used bandwidth. We used an algorithm called Multiple Objective Particle Swarm Optimization with Crowding Distance and Roulette Wheel to generate the non-dominated solutions, considering the average on- off gain and the ripple of the amplifier over the transmission bandwidth as the objectives in the optimization process. We designed amplifiers using three, four and five pump lasers. The experimental results showed that our proposal was able to design Raman amplifiers with a gain ripple lower than 0.2 dB and with an average on-off gain around 16.7 dB, when 20 signal channels and a total pump power of 1 W were considered. Moreover, we demonstrated that it is possible to allow the decision maker to choose among many possible non-dominated solutions depending on the application requirements.
This paper presents a wavelength assignment algorithm suitable for optical networks mainly impaired by physical layer effects, named the Intelligent Wavelength Assignment algorithm (iWA). The main idea is to determine the wavelength... more
This paper presents a wavelength assignment algorithm suitable for optical networks mainly impaired by physical layer effects, named the Intelligent Wavelength Assignment algorithm (iWA). The main idea is to determine the wavelength activation order for a first-fit algorithm that balances the impact of the physical layer effects by using a training algorithm inspired by evolutionary concepts. The iWA presents some recently proposed concepts in intelligent optimization algorithms, such as an external archive to store the best solutions. Some different physical layer effects, such as four-wave mixing and residual dispersion, were considered in the tests of our proposal. We tested our proposal for transparent optical networks. However, we believe iWA can be used in other types of network, such as opaque networks and translucent networks. The proposed wavelength assignment algorithm was compared with five other wavelength assignment algorithms for two network topologies in three different scenarios. The iWA algorithm outperformed the other WA algorithms in most cases. The robustness of our proposed algorithm to the load distribution changes was also analyzed.