Elastic optical networks (EONs) are able to provide high spectrum utilization efficiency due to flexibility in resource assignment. In translucent EONs, by employing regenerators and using advanced modulation formats ...
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Elastic optical networks (EONs) are able to provide high spectrum utilization efficiency due to flexibility in resource assignment. In translucent EONs, by employing regenerators and using advanced modulation formats for transmission, spectrum efficiency can be further improved. Survivability is regarded as an important aspect of EONs, and p-cycle protection is considered to be an attractive scheme due to its fast restoration and high protection efficiency. In this paper, we propose methods for evaluating and selecting p-cycles for both link protection (LP) and failure-independent path protection (FIPP) to survive single-link failures. After considering the various factors that affect the performance of a p-cycle, we propose two evaluation metrics for LP and FIPP, namely, individual p-cycle cost and set of cycles cost. Based on these metrics, we propose two algorithms for selecting a set of p-cycles in translucent EONs: Traffic Independent P-cycle Selection (TIPS), which selects a set of cycles without knowledge of the traffic, and Traffic-Oriented P-cycle Selection (TOPS), which takes given traffic information into account. A routing and spectrum assignment algorithm is designed for translucent EONs, and our p-cycle design algorithms are evaluated using both static and dynamic traffic models. Simulation results show that the proposed algorithms have better performance than commonly used baseline algorithms. We also compare the performance of LP p-cycles and FIPP p-cycles. (C) 2020 Optical Society of America
Traffic grooming techniques are used to combine low-speed individual requests for connections onto high-speed lightpaths in an efficient manner. Design of survivable grooming capable networks is of critical importance...
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Traffic grooming techniques are used to combine low-speed individual requests for connections onto high-speed lightpaths in an efficient manner. Design of survivable grooming capable networks is of critical importance. For such networks, protection may take place at the lightpath level or at the connection level. However, optimal formulations for implementing protection at either level are computationally intractable and can only be used for very small networks. We present an efficient integer linear program (ILP) formulation for the complete survivable traffic grooming problem, including topology design, traffic routing, and routing and wavelength assignment, using both dedicated and shared protection at the lightpath level. Unlike existing formulations, our ILP is able to generate optimal solutions for practical sized networks with hundreds of traffic requests. (C) 2008 Optical Society of America.
The technique of shortcuts to adiabaticity (STA) has attracted broad attention due to their possible applications in quantum information processing and quantum control. However, most studies published so far have been...
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The technique of shortcuts to adiabaticity (STA) has attracted broad attention due to their possible applications in quantum information processing and quantum control. However, most studies published so far have been only focused on Hermitian systems under the rotating-wave approximation (RWA). In this paper, we propose a modified shortcuts to adiabaticity technique to realize population transfer for a non-Hermitian system without RWA. We work out an exact expression for the control function and present examples consisting of two-and three-level systems with decay to show the theory. The results suggest that the shortcuts to adiabaticity technique presented here is robust for fast passages. We also find that the decay has small effect on the population transfer in the three-level system. To shed more light on the physics behind this result, we reduce the quantum three-level system to an effective two-level one with large detunings. The shortcuts to adiabaticity technique of effective two-level system is studied. Thereby the high-fidelity population transfer can be implemented in non-Hermitian systems by our method, and it works even without RWA. (C) 2017 Optical Society of America
Complex dynamics of natural particle systems, such as insect swarms, bird flocks, fish schools, has attracted great attention of scientists for years. Measuring 3D trajectory of each individual in a group is vital for...
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Complex dynamics of natural particle systems, such as insect swarms, bird flocks, fish schools, has attracted great attention of scientists for years. Measuring 3D trajectory of each individual in a group is vital for quantitative study of their dynamic properties, yet such empirical data is rare mainly due to the challenges of maintaining the identities of large numbers of individuals with similar visual features and frequent occlusions. We here present an automatic and efficient algorithm to track 3D motion trajectories of large numbers of moving particles using two video cameras. Our method solves this problem by formulating it as three linear assignment problems (LAP). For each video sequence, the first LAP obtains 2D tracks of moving targets and is able to maintain target identities in the presence of occlusions;the second one matches the visually similar targets across two views via a novel technique named maximum epipolar co-motion length (MECL), which is not only able to effectively reduce matching ambiguity but also further diminish the influence of frequent occlusions;the last one links 3D track segments into complete trajectories via computing a globally optimal assignment based on temporal and kinematic cues. Experiment results on simulated particle swarms with various particle densities validated the accuracy and robustness of the proposed method. As real-world case, our method successfully acquired 3D flight paths of fruit fly (Drosophila melanogaster) group comprising hundreds of freely flying individuals. (C) 2011 Optical Society of America
We investigate the effect of quantum-jump-based feedback on the dynamics of quantum discord for two noninteracting two-level atoms coupled to a single mode of the cavity field with and without the rotating-wave approx...
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We investigate the effect of quantum-jump-based feedback on the dynamics of quantum discord for two noninteracting two-level atoms coupled to a single mode of the cavity field with and without the rotating-wave approximation. It is found that the counterrotating terms can be helpful for generating steady states, and the value of steady-state quantum discord can be increased to approach 1 in the long-time limit by feedback controls. Furthermore, we also explore the influence of the time evolutions of mean excitation number in total systems and atomic subsystems on the quantum correlations and show that the enhancement of mean excitation number in atomic subsystems by feedback controls leads to the high value of steady-state quantum discord. (C) 2017 Optical Society of America
With the stringent requirements of high reliability and low latency, ultra-reliable low latency communications (URLLCs) are one of three typical services in the fifth generation of mobile network (5G) paradigm. The pa...
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With the stringent requirements of high reliability and low latency, ultra-reliable low latency communications (URLLCs) are one of three typical services in the fifth generation of mobile network (5G) paradigm. The packet duplication (PD) technique has been proposed as a promising solution to satisfy the extreme requirements of URLLC services. However, the benefit of PD comes at the cost of doubling resource usage. This paper investigates how to efficiently perform end-to-end URLLC slicing based on PD in 5G optical transport networks. Two heuristic algorithms are proposed, including PD-based slicing with wavelength isolation (PDS-WI) and PD-based slicing with link isolation (PDS-LI). The target of this paper is to maximize the number of accommodated URLLC slices by optimizing the allocation of heterogenous resources. The time complexity of these two algorithms is analyzed in detail. With dynamic slice requests, simulations are performed to evaluate and compare their performance in terms of slice blocking probability and resource usage. Meanwhile, two different network scenarios are considered in simulation. Simulation results indicate that PDS-WI outperforms PDS-LI by accommodating more URLLC slices. (C) 2020 Optical Society of America
Zernike polynomial orthogonality, an established mathematical principle, is leveraged with the Gauss-Legendre quadrature rule in a rapid novel approach to fitting data over a circular domain. This approach provides si...
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Zernike polynomial orthogonality, an established mathematical principle, is leveraged with the Gauss-Legendre quadrature rule in a rapid novel approach to fitting data over a circular domain. This approach provides significantly faster fitting speeds, in the order of thousands of times, while maintaining comparable error rates achieved with conventional least-square fitting techniques. We demonstrate the technique for fitting mid-spatial-frequencies (MSF) prevalent in small-tool-manufacturing typical of aspheric and freeform optics that are poised to soon permeate a wide range of optical technologies. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
Time division multiplexing-passive optical networks ( TDM-PONs) suffer from low upstream bandwidth utilization caused by guard band and various overheads. This degradation depends on optical network unit (ONU) numbers...
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Time division multiplexing-passive optical networks ( TDM-PONs) suffer from low upstream bandwidth utilization caused by guard band and various overheads. This degradation depends on optical network unit (ONU) numbers and cycle time, each of which has many effects on cost and quality, respectively. Upstream bandwidth utilization is efficiently increased by using two wavelength types at ONU sites so that overhead parts from two ONUs are overlapped in time. Each ONU is equipped with one of the two transmitting wavelengths, and an optical line terminal (OLT) schedules operation sequence. A utilization increase of up to 30% is achieved for gigabit Ethernet-passive optical network (GE-PON) by using the proposed scheme. Two operation algorithms, based on fairness and priority, are suggested and their performances are analyzed. (c) 2007 Optical Society of America.
We obtain explicit analytical expressions for the energy spectra of the resonant single- and two-photon Tavis-Cummings models in the asymptotic limit of a large number of atoms, A>> 1, and a large number of tota...
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We obtain explicit analytical expressions for the energy spectra of the resonant single- and two-photon Tavis-Cummings models in the asymptotic limit of a large number of atoms, A>> 1, and a large number of total excitations, N>> 1. We show that both the spectral singularities in the regime N/A similar to 1 and the equidistant spectra in the regime N/A >> 1 can be accurately described in the semiclassical framework. (c) 2024 Optica Publishing Group
We present a method to manipulate quantum states in open systems. It is shown that a high-fidelity quantum state may be generated by designing an additional Hamiltonian without rotating wave approximation. Moreover, w...
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We present a method to manipulate quantum states in open systems. It is shown that a high-fidelity quantum state may be generated by designing an additional Hamiltonian without rotating wave approximation. Moreover, we find that a coherent transfer is possible using quantum feedback control even when feedback parameters and noise strength can not be exactly controlled. Our results demonstrate the feasibility of constructing the shortcuts to adiabatic passage beyond rotating wave approximation in open systems. (C) 2016 Optical Society of America
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