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Optical Communications and Networking, IEEE/OSA Journal of

Issue 9 • Date Sept. 2013

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Displaying Results 1 - 19 of 19
  • [Front cover]

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  • [Front inside cover]

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  • Contents

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  • Proposal and performance evaluation of an efficient RZ-DQPSK modulation scheme in all-optical OFDM transmission systems

    Page(s): 932 - 944
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1467 KB) |  | HTML iconHTML  

    A return-to-zero differential quadrature phase-shift keying (DQPSK) modulation scheme is proposed for all-optical orthogonal frequency-division multiplexing transmission systems. The system uses coupler-based inverse fast Fourier transform/fast Fourier transform to support a 700 km single-mode fiber link and a transmission rate of 40 Gb/s without any nonlinear compensation. The performance of the proposed system is evaluated using simulation and four performance measures are obtained, namely, the eye diagram, the eye-opening penalty (EOP), the power spectral broadening, and the bit error rate(BER). The effect of self-phase modulation is taken into account in the performance evaluation. In addition, the performance of the proposed system is compared to that of a traditional one adopting a non-return-to-zero DQPSK scheme. Our results reveal that the proposed system outperforms the traditional one in all four aforementioned performance measures, yet the spectral efficiency is almost preserved. Specifically, for an input average power of 12 dBm, a reduction in both the required optical-signal-to-noise ratio of about 4 dB (to achieve a BER of 10-6) and the EOP of about 5 dB are reported when adopting the proposed system, as compared to the traditional one. View full abstract»

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  • Scaling star-coupler-based optical networks for avionics applications

    Page(s): 945 - 956
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1098 KB) |  | HTML iconHTML  

    In this work scaling of an optical broadcast-and-select network based on a passive star coupler is explored for avionics applications. Each client in the network is equipped with a transmitter unit and a multichannel receiver capable of receiving signals from all other clients connected to the star coupler. We propose a connecting node concept to scale the number of clients supported by the architecture. These connecting nodes act as bridges between star couplers, enabling the organization of several star couplers into a topology with additional clients. This design is modeled in the PhoenixSim simulation environment, and system-level simulation results are reported. We then propose the ring topology and dimension-N topology to interconnect and scale star couplers. Finally we compare the ring and dimension-N topologies in terms of scalability limit at different crossing traffic loads, revealing the trade-offs between latency, system complexity, and scalability. Our study shows that a robust, low-latency network of up to hundreds of clients, sufficient for current and next-generation avionics applications, can be built using off-the-shelf and near-term commercial technology. View full abstract»

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  • Load adaptive and fault tolerant framework for energy saving in fiber-wireless access networks

    Page(s): 957 - 967
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB) |  | HTML iconHTML  

    Energy saving (ES) in telecommunication networks is an important criterion when planning access networks. In fiber-wireless (FiWi) access networks the ES potential is high, when compared with other architectures, because different routes and optical access points can be used by routers at the wireless section. Although some proposals to increase energy efficiency in these architectures have been presented, these are not approaches that can adapt to variations in traffic load or distribution of traffic across the network. Here we fill this gap and propose a load adaptive and fault tolerant framework for ES in FiWi access networks. This framework allows optical network units (ONUs) to enter long-standing sleep mode under low traffic conditions, reducing energy waste, permitting fast reaction to ONU or fiber failures, and allowing quality of service (QoS) to be kept at a certain level. Results show that significant ES can be achieved under low to medium traffic loads while maintaining QoS and fault tolerance. View full abstract»

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  • Stochastic planning of dependable virtual infrastructures over optical datacenter networks

    Page(s): 968 - 979
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1145 KB) |  | HTML iconHTML  

    This paper focuses on the design of multiple dependable virtual infrastructures (VIs) over converged optical network and IT resources supporting uncertain elastic cloud services. VI dependability is defined as the VI ability to offer resilience in the case of IT resource failures and security guarantees in terms of isolation of VIs that share a common physical infrastructure. The VI planning optimization objective is to minimize the overall energy consumption. To address these issues together with the time variability and uncertainty of elastic cloud services, a novel VI planning scheme based on stochastic linear programming (SLP) is proposed. To cope with the increasing computational complexity inherently imposed in SLP formulations, the sample average approximation technique and Lagrangian relaxation are used to solve the SLP problem in an efficient manner. Our modeling results illustrate interesting trade-offs between the overall energy consumption of the VIs and the dependability impact on the energy consumption and the utilization of the infrastructure resources. View full abstract»

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  • Minimized spectrum resource consumption with rescaled failure probability constraint in flexible bandwidth optical networks

    Page(s): 980 - 993
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1385 KB) |  | HTML iconHTML  

    We investigate the problem of minimizing spectrum resource consumption for a set of connection requests in a flexible bandwidth optical network under the constraint that the failure probability of each connection must be below a specified threshold. To optimize the total frequency slots consumed, three schemes are proposed and evaluated: the rescaled failure-probability-aware algorithm (RFPA), the traffic cognition algorithm with rescaled failure probability (RFPTC), and an integer linear programming (ILP) model. We also introduce two traditional Dijkstra's algorithms with load balancing and spectrum assignment by first fit and traffic cognition (FF_DB and TC_DB) to compare with the proposed three schemes. For static traffic in a small network, the total frequency slots consumed by the RFPA and RFPTC algorithms will approach that of the optimal ILP solution as K increases, aswellastheaveragehops (AH). Furthermore, the average rescaled failure probabilities (RFPs) of the RFPA and RFPTC algorithms are much better than thoseof the ILP solutions. Inaddition, similarly, the results of the heuristic algorithms, FF_DB, TC_DB, RFPA, and RFPTC, in the large network have the same characteristics as in the small network. For dynamic traffic in a large network, the RFPTC algorithm reduces blocking probability and makes the best use of spectrum resources compared with the other schemes, which also reflects that discontinuous spectrum fragmentation is greatly reduced by the traffic cognition method. However, both RFPTC and RFPA result in much higher average RFP but perform fewer AH compared to TC_DB and FF_DB. View full abstract»

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  • Optical burst-switched SSB-OFDM using a fast switching SG-DBR laser

    Page(s): 994 - 1000
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (847 KB) |  | HTML iconHTML  

    The application of orthogonal frequency-division multiplexing (OFDM) in an optical burst-switched system employing a single fast switching sample grating-distributed Bragg reflector (SG-DBR) laser isdemonstrated experimentally. The effect of filter profiles compatible with 50, 25, and 12.5 GHz wavelength-division multiplexing grids on the system is investigated with system performance examined in terms of error vector magnitude per subcarrier for OFDM burst data beginning at various times after a switching event. Additionally the placement of the OFDM training sequence within the data burst and its effect on the system is investigated. View full abstract»

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  • Subcarrier intensity modulated MIMO optical communications in atmospheric turbulence

    Page(s): 1001 - 1009
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB) |  | HTML iconHTML  

    We investigate spatial diversity techniques for subcarrier phase-shift keying (PSK)-modulated optical wireless communication links over the Gamma-Gamma channels. Both repetition code and the Alamouti-type orthogonal space-time block code (OSTBC) are considered. Highly accurate series error rate expressions are derived by using a moment generating function approach with a series expansion of the modified Bessel function. Truncation error analyses and asymptotic error rate analyses are also presented. Our asymptotic analyses show that the diversity order of the studied system depends only on the effective number of small-scale cells of the scattering process in the atmosphere. Our performance analyses confirm that the repetition code outperforms OSTBC for subcarrier PSK-based systems over the Gamma-Gamma channels. The asymptotic performance loss of the Alamouti-coded system with respect to the repetition-coded system is also quantified analytically. View full abstract»

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  • Optimization scheme for WDM-based transmission technology selection in future passive optical networks

    Page(s): 1010 - 1020
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (741 KB) |  | HTML iconHTML  

    Future passive optical networks (PONs) are expected to support much larger capacity and much wider coverage. How to jointly address these two design requirements represents one of the most challenging aspects in today's research on PONs. So far, most research efforts have been devoted to devising new architectural or technological solutionsto support such stringent requirements. In particular, the technology to be used for transmission may have diverse multiplexing techniques, types of transceivers, modulation formats, and detection techniques. However, the question of which transmission technology is the most effective considering the trade-offs in terms of complexity, offered capacity, and reach is still open. In this paper, we aim at answering this question comparing the use of time division multiplexing (TDM), wavelength division multiplexing (WDM), and hybrid TDM/WDM techniques in PONs. To achieve this goal, we first categorize the main options for transmission technologies in PONs in three families: colored dense WDM (DWDM), tunable DWDM, and colorless DWDM. Then, we propose a new optimization scheme that selects the optimal transmission technology for different operational scenarios that are defined by varying the number of users, the distance to the users, and the traffic load. The choice of the passive optical components to be used at the remote node is also part of the optimization scheme given its significant impact on the choiceof the transmission technology. As a result, we report and discuss which transmission technologies are the most suitable under different operational scenarios. View full abstract»

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  • Slick lightpath reconfiguration using spare resources

    Page(s): 1021 - 1031
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (603 KB) |  | HTML iconHTML  

    This paper presents different methods to solve the network reconfiguration problem in wavelength-switching optical networks. The network reconfiguration problem consists of finding a sequence of operations that can be used to migrate traffic from one lightpath configuration to another. Operations correspond to establishing or tearing down a given lightpath. The methods presented exploit for the first time (to our knowledge) the structure of the underlying combinatorial problems in order to divide the reconfiguration process into independent stages, decreasing the amount of disrupted traffic. Our numerical results show that our approaches can reduce the number of disruptions up to 10% more than the traditional approach (computing the minimum feedback vertex set of the dependency graph), while releasing 40%of seized resources during the reconfiguration process. The methodology presented can be easily adapted to other circuit-switching technologies, such as flexpaths. View full abstract»

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  • Capacity analysis of dual amplify-and-forward relayed free-space optical communication systems over turbulence channels with pointing errors

    Page(s): 1032 - 1042
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (831 KB) |  | HTML iconHTML  

    This paper elaborates on the end-to-end capacity of dual-hop free-space optical (FSO) communication systems employing amplify-and-forward (AF) relaying, assuming channel state information is only known at the receiving terminals. The relay is assumed to either possess perfect channel state information or have a fixed gain. The performance of the considered system is affected by the combined effects of atmospheric turbulence-induced fading, pointing errors (i.e., misalignment fading), and path loss. Atmospheric turbulence conditions are modeled using the gamma-gamma distribution. For the system under consideration, accurate analytical approximations as well as upper bounds to the ergodic capacity are derived. In addition, bound approximations in the high signal-to-noise ratio regime are deduced that provide valuable insights into the impact of model parameters on the capacity of AF FSO dual-hop relaying systems. Numerically evaluated and computer simulation results are further provided to demonstrate the validity of the proposed mathematical analysis. View full abstract»

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  • Collision-free bandwidth-variable optical burst switching ring network

    Page(s): 1043 - 1056
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1436 KB) |  | HTML iconHTML  

    Recently, flexible bandwidth allocation has been proposed in an orthogonal frequency division multiplexing based elastic optical network, which is a promising technology for 100G and beyond optical networks. In this paper, for the first time we introduce flexible bandwidth to an optical burst switching (OBS) ring network and propose a novel bandwidth-variable OBS (BV-OBS) ring network. In the proposed BV-OBS ring network, the durations of bursts are fixed to one timeslot in the time domain, while the bandwidths are variable in the frequency domain according to the burst size. With fixed burst duration and variable bandwidth, the BV-OBS ring can achieve the state of being collision free with high bandwidth efficiency. Simulation results show that a BV-OBS ring network outperforms previous OBS rings proposed in wavelength division multiplexing networks in both network throughput and end-to-end delay. View full abstract»

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  • Establishment of dynamic lightpaths in filterless optical networks

    Page(s): 1057 - 1065
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (554 KB) |  | HTML iconHTML  

    In this paper, we study the performance of dynamic routing and wavelength assignment (RWA) in filterless optical networks. These types of broadcast and select networks benefit from breakthroughs in advanced transmission technologies for replacing optical filters and active photonic switching devices, such as wavelength selective switches, with passive optical interconnections between nodes, creating passive optical light trees. We introduce an RWA scheme for establishing passive optical lightpaths in a filterless context and managing unfiltered channels at intermediate egress nodes, which, by propagating downstream of the terminating nodes, participate in wavelength usage and increase the risk of wavelength exhaustion. Simulation results are presented for six network topologies, along with the performance evaluation of active photonic and filterless optical network solutions with static and dynamic RWA schemes. We show that the performance of the proposed scheme depends on the average degree of node connectivity. View full abstract»

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  • OpenFlow-based segment protection in Ethernet networks

    Page(s): 1066 - 1075
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (729 KB) |  | HTML iconHTML  

    Metro and carrier-grade Ethernet networks, as well as industrial area networks and specific local area networks (LANs), have to guarantee fast resiliency upon network failure. However, the current OpenFlow architecture, originally designed for LANs, does not include effective mechanisms for fast resiliency. In this paper, the OpenFlow architecture is enhanced to support segment protection in Ethernet-based networks. Novel mechanisms have been specifically introduced to maintain working and backup flows at different priorities and to guarantee effective network resource utilization when the failed link is recovered. Emulation and experimental demonstration implementation results show that the proposed architecture avoids both the utilization of a full-state controller and the intervention of the controller upon failure, thus guaranteeing a recovery time only due to the failure detection time, i.e., a few tens of milliseconds within the considered scenario. View full abstract»

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  • Ultra-wideband and 60-GHz generation and transmission over a wavelength division multiplexing-passive optical network

    Page(s): 1076 - 1082
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (900 KB) |  | HTML iconHTML  

    A novel scheme to simultaneously generate an on-off keying (OOK) impulse radio ultra-wideband (IR-UWB) signal, a 60-GHz millimeter-wave (mmW) signal, and a baseband signal in the optical domain using a Sagnac loop is proposed and demonstrated. In the proposed system, a polarization beam splitter (PBS), a fiber Bragg grating (FBG), and two back-to-back connected polarization modulators (PolMs) are incorporated in the Sagnac loop. An OOK Gaussian pulse signal is modulated on a clockwise transmitted optical carrier by the first PolM and then converted to an OOK UWB impulse signal at the FBG serving as an edge filter, and the counterclockwise transmitted optical carrier is simultaneously modulated by a baseband signal and a 30-GHz mmW signal at the second PolM. By introducing a ¿ phase shift between the clockwise and counterclockwise optical carriers, the optical carrier of the 30-GHz signal is suppressed when applied to a polarizer. As a result, a frequency-doubled mmW signal at 60 GHz is generated by beating the two first order sidebands at a photodetector. Due to the velocity mismatch between the counterclockwise light wave and the clockwise microwave carrier, the OOK signal and the baseband signal can travel through the other PolM with negligible modulation; thus no interference from another signal would be introduced. Error-free transmission of a UWB signal at 2.5 Gbps and a wired baseband signal at 2.5 and 5 Gbps over a 25-km single-mode fiber is achieved. A frequency-doubled mmW signal at 60 GHz is also obtained. View full abstract»

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  • Architecture discovery enabled resource allocation mechanism for next generation optical-wireless converged networks

    Page(s): 1083 - 1095
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1196 KB) |  | HTML iconHTML  

    Optical-wireless convergence is identified as a promising solution to facilitate quality-of-service (QoS)-guaranteed, ubiquitous, and high-bandwidth access to end users. Different converged network architectures can be deployed depending on individual circumstances to achieve improved performance without compromising cost-effectiveness. However, with different network architectures, different resource allocation mechanisms are required to achieve the best performance. This is problematic in both the deployment and operational phases. In this paper, we propose an architecture discovery enabled resource allocation (ADERA) mechanism for the long term evolution (LTE)-gigabit Ethernet passive optical network (GEPON) converged network. The proposed ADERA is a self-adaptive algorithm ¿ it discovers the underlying architecture of the network by analyzing control signals and eventually evolves into an effective resource handling mechanism for the respective architecture. In addition, ADERA leverages inherited features of both the LTE network and GEPON in conjunction with the characteristics of their frame structures to improve the overall network performance. For example, ADERA is incorporated with a near-future traffic forecasting mechanism for efficient resource allocation. Using simulations, we evaluate the performance of our proposed ADERA algorithm and compare it against other existing resource allocation mechanisms. Our results indicate that ADERA achieves improved QoS performance in the converged network irrespective of the architecture used for the deployment. View full abstract»

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  • All programmable and synthetic optical network: Architecture and implementation

    Page(s): 1096 - 1110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2362 KB) |  | HTML iconHTML  

    This paper reports on the design, implementation, and evaluation of a multitechnology, multirate, and adaptable network architecture for metropolitan/edge areas. It is empowered by programmability in control and data planes, providing users with an open network platform to redefine and optimize its behavior and performance. It uses a hybrid data plane of fixed-grid [(sub)wave-length] and flex-grid systems to support a broad range of data rates (1 to 555 Gb/s). The programmability in the data plane is achieved by building the nodes with a modular and flexible architecture (architecture on demand nodes) to achieve different functionalities (fixed-/flex-grid switching with or without time multiplexing) on demand. A centralized, modular, and scalable control framework has been constructed for this network. It uses a set of software plug-ins designed for architecture synthesis and adaptation for policing network resources access and as algorithms of routing and resource allocation for network operation. The proposed hybrid network architecture, along with allocation policies and resource allocation algorithms, is evaluated through simulations across a broad range of traffic profiles with bandwidth requests stretching from 1 to 400 Gb/s. Finally, the programmable data-plane/control-plane architecture has been implemented in an experimental testbed and the functionality of the node and network elements individually and together have been tested, demonstrating the feasibility of the system. View full abstract»

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Aims & Scope

IEEE/OSA Journal of Optical Communications and Networking covers advances in the state-of-the-art of optical communications and networks.

Full Aims & Scope

Meet Our Editors

Editors-in-Chief
Patrick Iannone
  Alcatel-Lucent Bell Labs
Ori Gerstel
   Cisco Systems, Inc.