We propose a kind of Yb2?–Yb3?-codoped glass,which is used as spectral converter layer to adjust AM1.5 solar spectrum for a better match with silicon *** energy-level rate equations and power transmission equations a...
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We propose a kind of Yb2?–Yb3?-codoped glass,which is used as spectral converter layer to adjust AM1.5 solar spectrum for a better match with silicon *** energy-level rate equations and power transmission equations are established to analyze the down-conversional effect of the codoped glass on solar *** numerical results show that with proper doping concentration and thickness the glass layer may improve conversion efficiency by about 12%.Moreover,we also apply the modified spectrum as excitation source of solar cell in a simulation platform,and reveal that there is about 15%improvement in practical cells.
The emerging intelligence technologies represented by deep learning have broadened their applications to various fields. Beyond the conventional electronics-based processing systems, the convergence of photonics and a...
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The emerging intelligence technologies represented by deep learning have broadened their applications to various fields. Beyond the conventional electronics-based processing systems, the convergence of photonics and artificial intelligence(AI) technology enhances the performance and learning ability of AI. In this review, we propose the concept of an intelligent photonic system(IPS), illustrating it as a developing architecture with three different versions. For each version of IPS, we review several representative *** we discuss the challenges towards an IPS and provide some prospects for the future development.
Over the past few decades, the demand for the capacity and reliability of opticalnetworks has continued to grow. In the meantime, opticalnetworks with larger knowledge scales have become sources of numerous heteroge...
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Over the past few decades, the demand for the capacity and reliability of opticalnetworks has continued to grow. In the meantime, opticalnetworks with larger knowledge scales have become sources of numerous heterogeneous data. In order to handle these new challenges, many issues need to be resolved,among which the low-margin opticalnetworks design, power optimization, routing and wavelength assignment(RWA), failure management are quite important. However, the use of traditional algorithms in the above four applications shows some shortcomings. Fortunately, artificial intelligence(AI), especially machine learning(ML), is regarded as one of the most promising methods to overcome these shortcomings. In this study, we review the applications of ML methods in solving these four issues. Although many ML-based researches have emerged, the applications of ML techniques in opticalnetworks still face challenges. Therefore, we also discuss some possible future directions of investigating ML-based approaches in opticalnetworks.
We propose and demonstrate a simple configuration of wavelength-tunable fiber laser made up of a tunable band-pass filter, a Sagnac loop refiector, and a Fabry-Perot laser diode. Based on the self-seeded operation, th...
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We propose and demonstrate a simple configuration of wavelength-tunable fiber laser made up of a tunable band-pass filter, a Sagnac loop refiector, and a Fabry-Perot laser diode. Based on the self-seeded operation, the proposed fiber laser can obtain a single-longitudinal-mode output in the wavelength tuning range of 1544.69–1563.39 nm with tuning step of 1.34 nm. The performances of output power (-9 dBm), optical side-mode suppression ratio ( 65.5 dB), and power and wavelength stabilities are well exhibited.
Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network a...
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Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network and high data rate at the hot ***,it is not permissible to assign orthogonal pilot sequences for all the supported users due to the large ***,we propose a pilot reduction scheme based on the heterogeneous system configurations and the unique topology of this *** reusing of pilot sequences causes the presence of the contaminated channel state information(CSI) and results in receivers' Quality of Service(QoS) *** the contaminated CSI,we provide an energy-efficient beamforming based on minimizing the total power consumption while keeping the QoS constraints satisfied and restricting the QoS outage probability below a given *** applying the approach of Bernstein approximation and semi-definite relaxation,we transform the original intractable chance constrained program to a convex problem *** results show that the average power consumption of the proposed beamforming for our pilot reduction scheme is close to that of the perfect CSI *** our scheme will greatly compress the length of pilot sequence especially for those highly densified network with large number of small cells,it will be crucially helpful to put such two-tier massive multiple-input and multiple-output(MIMO) systems into practice.
We propose a new scheme to generate broadband linearized optical single-sideband (OSSB) signal for radio over fiber systems. By using an unbalanced dual parallel Mach-zehnder modulator (DPMZM) followed by optical ...
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We propose a new scheme to generate broadband linearized optical single-sideband (OSSB) signal for radio over fiber systems. By using an unbalanced dual parallel Mach-zehnder modulator (DPMZM) followed by optical filtering, a linearized OSSB signal is obtained. With coherent detection, radio frequency (RF) signal can be recovered with simultaneously suppressed second-order distortion and third-order intermodulation. This scheme can be used to realize broadband systems with wide dynamic range.
A 100-Gb/s high-speed optical transmitter is proposed and experimentally demonstrated. Based on frequency-quadrupling technique, two sub-channels with a fixed 50-GHz spacing are obtained from one laser source. Using r...
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A 100-Gb/s high-speed optical transmitter is proposed and experimentally demonstrated. Based on frequency-quadrupling technique, two sub-channels with a fixed 50-GHz spacing are obtained from one laser source. Using return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) modulation format and polarization multiplexing (PolMux), only low-speed electronic devices of 12.5 GHz are needed for the 100-Gb/s transmitter. This eliminates the need of ultrahigh-speed optoelectronic devices and thus greatly reduces the cost. The experimental results show that this transmitter can achieve good performance in dispersion tolerance of a 25-km single mode fiber (SMF).
We propose a 40-Gb/s star 16-ary quadrature amplitude modulation (16-QAM) transmitter using a single dual-drive Mach-Zehnder modulator (DDMZM). This transmitter is demonstrated through experiment and simulation an...
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We propose a 40-Gb/s star 16-ary quadrature amplitude modulation (16-QAM) transmitter using a single dual-drive Mach-Zehnder modulator (DDMZM). This transmitter is demonstrated through experiment and simulation and shows the advantage of simplicity for implementation. Simulation results indicate that error free performance could be achieved for the generated signal after 80-km standard single-mode fiber (SSMF) transmission with coherent detection scheme.
The concept of Peer-to-Peer (P2P) has been in-troduced into mobile networks, which has led to the emer-gence of mobile P2P networks, and originated potential ap-plications in many fields. However, mobile P2P networks ...
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The concept of Peer-to-Peer (P2P) has been in-troduced into mobile networks, which has led to the emer-gence of mobile P2P networks, and originated potential ap-plications in many fields. However, mobile P2P networks are subject to the limitations of transmission range, and highly dynamic and unpredictable network topology, giving rise to many new challenges for efficient information retrieval. In this paper, we propose an automatic and economical hybrid information retrieval approach based on cooperative cache. In this method, the region covered by a mobile P2P network is partitioned into subregions, each of which is identified by a unique ID and known to all peers. All the subregions then constitute a mobile Kademlia (MKad) network. The pro-posed hybrid retrieval approach aims to utilize the flooding-based and Distributed Hash Table (DHT)-based schemes in MKad for indexing and searching according to the designed utility functions. To further facilitate information retrieval, we present an effective cache update method by considering all relevant factors. At the same time, the combination of two different methods for cache update is also introduced. One of them is pull based on time stamp including two different pulls: an on-demand pull and a periodical pull, and the other is a push strategy using update records. Furthermore, we provide detailed mathematical analysis on the cache hit ratio of our approach. Simulation experiments in NS-2 showed that the proposed approach is more accurate and efficient than the existing methods.
The articles in this special section focus on the development and applications supported by new smart grid technologies. The term smart grid means different things to different people, and quite rightly so. Our relati...
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The articles in this special section focus on the development and applications supported by new smart grid technologies. The term smart grid means different things to different people, and quite rightly so. Our relationship with electricity varies significantly around the world. Many countries are trying to decarbonize their electricity systems; for them, a smart grid should be able to integrate large volumes of renewables. In other parts of the globe, the main concern is reducing the number of outages during common and uncommon events (such as natural disasters). For these countries, a smart grid is one that uses innovative solutions to increase reliability and also to make the grid more resilient. We also have countries that simply want to use electricity more efficiently; hence, a smart grid should help, for instance, in reducing technical and nontechnical losses. On the other side of the spectrum, we cannot forget that around a billion people in the world still do not have access to electricity. For those countries, cost-effectiveness and remoteness are major challenges, and a smart grid might be able to bring about innovative yet inexpensive community-based solutions. It is because of this diversity of contexts and objectives that different implementations of smart grid concepts have emerged in the last few years—and continue to emerge.
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