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A scheme for optical parallel encryption/decryption of quadrature phase shift keying (QPSK) signals is proposed, in which three QPSK signals at 10 Gb/s are encrypted and decrypted simultaneously in the optical domain through nondegenerate four-wave mixing in a highly nonlinear fiber. The results of theoretical analysis and simulations show that the scheme can perform high-speed wiretapping against the encryption of parallel signals and receiver sensitivities of encrypted signal and the decrypted signal are -25.9 and -23.8 dBm, respectively, at the forward error correction threshold. The results are useful for designing high-speed encryption/ decryption of advanced modulated signals and thus enhancing the physical layer security of optical networks. [ABSTRACT FROM AUTHOR]

As the scale of the intra-data center network (DCN) grows even larger, the traditional electrical switching has reached a bottle neck in terms of energy consumption, bandwidth provision, and end-to-end latency. Different approaches have been made by employing the optical switch instead of the electrical ones to solve the bandwidth as well as the energy efficiency and the latency problem. We propose a DCN architecture based on cascaded microelectromechanical systems switches for dynamic DCN connectivity provisioning. This architecture provides high port count, which attributes to the demands of the intradata center traffic. Multiple points to one point switching scenario is experimentally demonstrated through this data center interconnect. Numerical simulation is employed to investigate the performance of the proposed architecture. The results show that the blocking probability and latency decrease as the scale of the architecture is upgraded. [ABSTRACT FROM AUTHOR]

A system of generating and receiving orbital angular momentum (OAM) radio beams, which are collectively formed by two circular array antennas (CAAs) and effectively optimized by two intensity controlled masks, is proposed and experimentally investigated. The scheme is effective in blocking of the unwanted OAM modes and enhancing the power of received radio signals, which results in the capacity gain of system and extended transmission distance of the OAM radio beams. The operation principle of the intensity controlled masks, which can be regarded as both collimator and filter, is feasible and simple to realize. Numerical simulations of intensity and phase distributions at each key cross-sectional plane of the radio beams demonstrate the collimated results. The experimental results match well with the theoretical analysis and the receive distance of the OAM radio beam at radio frequency (RF) 20GHz is extended up to 200 times of the wavelength of the RF signals, the measured distance is 5 times of the original measured distance. C The presented proof-of-concept experiment demonstrates the feasibility of the system. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of spectrum-aware survivable strategies with failure probability constraints under static traffic in flexible bandwidth optical networks. The joint failure probability between primary and backup paths must be below the maximum tolerable joint failure probability for each traffic demand. We develop integer linear program (ILP) models for dedicated-path protection and shared-path protection in order to minimize the total number of frequency slots consumed, and we also propose a spectrum-aware dedicated protection (SADP) algorithm and a spectrum-aware shared protection (SASP) algorithm. Simulation results show that the ILP model solutions consume minimum number of frequency slots, but lead to higher average joint failure probability compared to the SADP and SASP algorithms. Moreover, both the SADP and SASP algorithms achieve a better performance in terms of total number of frequency slots consumed as compared to a conventional dedicated-path protection algorithm and a conventional shared-path protection algorithm, respectively, but lead to higher average joint failure probability. [ABSTRACT FROM PUBLISHER]

As is well known, elastic optical network is quite attractive due to its great spectral efficiency and flexibility, which can allocate appropriate size spectrum based on efficient modulation modes such as Orthogonal Frequency Division Multiplexing (OFDM) modulation, etc. These characters are able to better meet the needs of the intra-data-center optical interconnection. To properly analyze and operate elastic optical networks with highly dynamic traffic of the intra-data-center, considering the continuity constraint and the contiguity constraint, efficient methods are required for the on-line routing and spectrum allocation (RSA) issue. In this paper, we propose two methods (AFD and CSL) for assessing the status (spectrum fragmentation) of the network, and present two algorithms (BSPR and HSR) which use the proposed assessment value to perform on-line RSA applied to intra-data-center networks which adopt the Software-Defined Network (SDN) control mode. Simulation results reveal that the proposed approaches allow solving the on-line RSA problem more efficiently with lower blocking probability of the networks. [ABSTRACT FROM AUTHOR]

The capability of multicast directly in the optical domain at the routing nodes is a target for energy saving, fast service provisioning, and effective network resource utilization. An optical network node architecture supporting wavelength conversion, unicast, and multicast is presented and a shared multicast/wavelength conversion module is designed in the intermediate node. Wavelength conversion and one-to-six WDM multicast of 25-Gb/s QPSK signals based on four-wave mixing are experimentally demonstrated using a semiconductor optical amplifier with only two pumps. All six multicast signals achieve error-free performance with a power penalty <;4.3 dB. [ABSTRACT FROM PUBLISHER]

Data centers have to sustain the rapid growth of data traffic due to the increasing demand of bandwidth- hungry Internet services. The current fat tree topology causes communication bottlenecks in the server interaction process, resulting in power-hungry O-E-O conversions that limit the minimum latency and the power efficiency of these systems. As a result, recent efforts have advocated that all optical data center networks (DCNs) have the capability to adapt to traffic requirements on demand. We present the design, implementation, and evaluation of a cascaded microelectromechanical systems switches-based DCN architecture which dynamically changes its topology and link capacities, thereby achieving unprecedented flexibility to adapt to dynamic traffic patterns. We analyze it under a data center traffic model to determine its suitability for this type of environment. The proposed architecture can be scaled to 3300 input/output ports by available experimental components with low blocking probability and latency. The blocking probability and latency are about 0.03 and 72 ms at a moderate traffic load for 32 input/output ports based on our numerical results, which are much smaller than the results for 4 input/output ports which are 0.13 and 235 ms, respectively. [ABSTRACT FROM AUTHOR]

Abstract  The emergence of new services demands for a multicast function in optical networks. At the same time, wavelength converters are introduced to increase the efficiency of wavelength usage. It is because of the high cost and complex architecture of optical multicast and wavelength conversion technology, that a new switch structure is introduced, in which optical splitters and wavelength converters are shared per-node. In order to accommodate this architecture, a multicast routing and wavelength assignment algorithm in a splitter–converter-sharing optical network and a changing link weight policy to balance network traffic are proposed. By extending RSVP-TE (Resource ReSerVation Protocol-Traffic Engineering) and OSPF-TE (Open Shortest Path First-Traffic Engineering), an optical multicast mechanism is provided, and message type, signaling flow, and finite state machine model are given. Simulations of NSFNET show that, when the number of splitters and converters are 50% and 12.5% of the full equipment respectively, the performance is close to the ideal case. Using a changing link weight policy can improve performance greatly, when there are enough splitters and converters. [ABSTRACT FROM AUTHOR]

This paper demonstrates the theory of chromatic dispersion (CD)-induced constellation rotation (CR) in a radio-over-fiber (ROF) link, and a symmetry theory for compensation. A 60 GHz full-duplex ROF system with vector signal transmission using frequency-tripling modulation (FTM) is also proposed. The simulations for both 5 Gbps and 200 Mbps 16 QAM signal transmission show that the CD-induced CR can be entirely overcome due to the proposed method, and the proposed ROF schedule still maintains good performance even after 500 km of 200 Mbps vector signal transmission. Meanwhile, the central station is significantly simplified and cost-effective since only one 15 GHz local oscillator is needed for both the generation of an optical millimeter-wave signal and the carrier of the downlink intermediate-frequency (IF) signal. [ABSTRACT FROM AUTHOR]

A magnetically tunable metamaterial perfect absorber (MPA) based on ferromagnetic resonance is experimentally and numerically demonstrated. The ferrite-based MPA is composed of an array of ferrite rods and a metallic ground plane. Frequency dependent absorption of the ferrite-based MPA under a series of applied magnetic fields is discussed. An absorption peak induced by ferromagnetic resonance appears in the range of 8–12 GHz under a certain magnetic field. Both the simulated and experimental results demonstrate that the absorption frequency of the ferrite-based MPA can be tuned by the applied magnetic field. This work provides an effective way to fabricate the magnetically tunable metamaterial perfect absorber. [ABSTRACT FROM AUTHOR]