最新刊期
卷 ， 期 6 ， 2019
- 摘要：All-optical chaotic communication plays an important role in chaotic communication due to its simple structure and high complexity. Chaos synchronization is the most important part in chaotic optical communication, requiring the perfect parameter matching of the chaotic transmitter and receiver. Due to the difficulty of perfect devices matching, the practical applications of chaotic optical communications are limited. This paper proposed a method of modeling the chaotic laser using neural network, which can significantly simplify the structure of the chaotic receiver while keeping the system security. A 5 Gbit/s signal transmission of non-return-to-zero message hidden in a chaotic optical carrier is successfully experimentally demonstrated. This method greatly reduces the complexity of all-optical chaos synchronization and provides the possibility of point-to-multipoint all-optical chaotic communication.关键词：all-optical chaotic communication;neural network;chaos prediction
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发布时间： - 摘要：In order to guarantee both the survivability of optical network and Quality of Service（QoS）, we introduce a crosstalk-evaluated approach by considering the inter-core spectrum status when establishing connection requests in Spatial Division Multiplexing Elastic Optical Networks（SDM-EONs） with Multicore Fiber（MCF）. Considering the survivability of optical networks and the crosstalk-evaluated approach, a new crosstalk-aware dedicated protection approach based on service bandwidth classification and the corresponding algorithm are proposed in SDM-EONs. For comparison, we also introduce three other traditional dedicated protection algorithms in SDM-EONs. Simulation results show that the proposed algorithm achieves lower blocking probability and doesn’t dramatically increase average crosstalk compared to three other traditional dedicated protection algorithms in SDM-EONs.关键词：dedicated protection;service bandwidth classification;crosstalk awareness;SDM-EONs
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发布时间： - 摘要：In order to improve the operation and maintenance level of smart substation communication network, a packet forwarding path search algorithm based on block matrix is proposed, which solves the disadvantages of the matrix large computation and slow computation speed. The physical network topology matrix model and logical network topology matrix model are established. The mapping relationship is constructed to give the flow of message path finding algorithm. In order to solve the problem of large amount of computation in network topology analysis by matrix method, this paper presents an optimization algorithm based on block matrix technology and assisted by sparse matrix and symmetric matrix technology. The network matrix model is divided into several sub-matrices by genetic algorithm, and the sub-matrices are processed by sparse matrix and symmetric matrix technology. Through the network analysis of substation, this algorithm can not only find the forwarding path of the message, but also take up less memory space and faster calculation speed.关键词：smart substation;communication network;genetic algorithm;sparse matrix;symmetric matrix
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发布时间： - 摘要：In order to improve the bandwidth of the modern phased array radar, a novel beamforming system based on paralleled Chirped Microwave Pulse（CMP） generators is proposed in this paper. In each path, a Microwave Photonic Filters（MPF） with a quadratic phase response is configured, which are equivalently realized by using nonuniformly spaced taps. The CMPs can be generated by applying an Ultra-Wideband signal to the paralleled MPFs. By tuning the wavelengths of optical carriers in the paths, the group delays of the signals can be tuned depend on the fiber dispersion, realizing squint-free beamforming for the CMP. As the parameters of the MPFs and CMP signals can be variable, the system is quite flexible. By numerical simulation, the feasibility of beamforming and direction steering of the beamforming system are verified. Besides, the research results will contribute to the development of modern phased array radars.关键词：CMP;beamforming;microwave photonics filter;group delay
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发布时间： - 摘要：Problems of bit error rate rising due to Optical Signal-to-Noise Ratio（OSNR） worsening in beyond-100 Gbit/s optical network can be overcomed by utilizing feed Forward Error Correction（FEC） codes which are comprehensively applied in optical networks. Traditional encoders with high latency cannot meet the requirements of high-speed optical network, and studies on high-speed encoder are seldom. Studies on decoders usually focus on key equation solving algorithms rather than low latency decoding schemes. A parallel encoding and decoding scheme is proposed in this paper for KP4 FEC, i.e. RS（544,514） code, with the encoder’s throughput reaching above 17 Gbit/s, and latency lower than 0.3 μs, while the decoder’s throughput reaching above 66 Gbit/s, and latency lower than 0.17 μs.关键词：beyond 100 Gbit/s optical network;KP4 FEC;low latency;Reed-Solomon parallel encoding;Reed-Solomon parallel decoding
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发布时间： - 摘要：In 5 G forward network, single fiber bidirectional technology is one of the important characteristics. Compared with single-fiber bidirectional technology in 4 G and Fiber To The X（FTTx） networks, single-fiber bidirectional technology in 5 G forward network is more complex. In this paper, several schemes to realize single-fiber bidirectional transmission in 5 G forward network are first introduced. Then the key optical devices to realize single-fiber bidirectional transmission and the crosstalk problem of single-fiber bidirectional system are analyzed. The comparison result shows that the single-fiber bidirectional scheme based on a single Dense Wavelength Division Multiplexing（DWDM） device has more advantages than the single-fiber bidirectional scheme based on an optical ring device.关键词：wireless forward network;single-fiber bidirectional;DWDM;wavelength planning;crosstalk
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发布时间： - 摘要：Semiconductor silicon nanoparticles have many novel electromagnetic properties and have became a research hotspot in optoelectronics in recent years. In order to improve the luminescence intensity of Quantum Dot（QD） photoluminescence devices, a dimer composed of two silicon nano-cubes of different sizes is proposed. By the Finite Difference Time Domain（FDTD） method, the luminescence enhancement of QD by silicon nano-dimers is studied in terms of fluorescence excitation rate enhancement and quantum yield enhancement. The results show that the dimer composed of two silicon cubes with different sizes can enhance the luminescence of CdSe QDs. When the side length of the two silicon nano-cubes and the gap between them getting smaller, the fluorescence excitation rate enhancement factor and the quantum yield enhancement factor of the QDs tend to increase gradually. In particular, when the side lengths of two silicon nano-cubes are 100 nm and the gap of the silicon dimer is 20 nm, the structure of silicon nano-dimer is optimal, and the fluorescence intensity of CdSe QDs can be enhanced by about 24 times.关键词：optoelectronics;light emitting device;light radiation enhancement;nano-material
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发布时间： - 摘要：For the problems of narrow adjustable range, large loss and low bandwidth accuracy in the optical filter module for traditional fiber-optic communication systems, a large bandwidth linear modulation optical filter based on FBG is designed. The modulation system is composed of a light source, a strain-sensitive Fiber Bragg Grating（FBG）, an adjustable strain structure, and a demodulator. A large-scale continuous modulation of the strain is realized by the screw fine-tuning structure, and the linear correlation between the strain amount and the echo wavelength offset is calculated by the combination of the strain beam and the FBG. The simulation analysis shows the peak reflectance of the reflected light as a function of the reflection bandwidth under different FBG parameters, and the relevant parameters are selected accordingly. We conduct an experiment by continuous changing the force values to test the reflected light power, echo central wavelength and echo spectrum. The results show that for every 0.1 mm change, the average central wavelength shift is 415 pm, and the linearity is high. The linearity is better than 0.98, and the modulation range is 1 545～1 565 nm, which can achieve large-bandwidth continuous linear modulation. In conclusion, the structure can be used in a fiber optic communication system that requires a wide range of continuously adjustable filtering modules, and has certain application value.关键词：optical fiber communication;optical filtering;large bandwidth linear modulation;micro strain
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发布时间： - 摘要：In tunable laser,grating fabrication is complicated and expensive. In this paper, a sampled gratings based Distributed Bragg Reflector（DBR） tunable laser is designed to reduce the cost of tunable laser. We propose to use sampled gratings instead of uniform gratings in this paper. Low-cost DBR lasers with different tuning range can be monolithically integrated in the same chip by conventional holographic interferometry method. Based on the simulation results, we find that this type of DBR laser can reach more than 45 dB Side Mode Suppression Ratio（SMSR） and 10 nm tuning range. Based on several DBR lasers with different sampled period, the total tuning range can be more than 40 nm.关键词：Semiconductor laser;monolithic PICs;tunable laser
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发布时间： - 摘要：In the massive Multiple-Input Multiple-Output（MIMO） system, when the number of users is comparable（or equal） to the number of Base Station（BS） antennas, the performance of the linear detection algorithm is not ideal. We start with nonlinear detection and propose a greedy sphere decoding algorithm based on Lattice Reduction（LR）. Lenstra-Lenstra-Lovasz algorithm assisted QR decomposition is proposed to obtain orthogonal bases, which then combines the improved sphere decoding algorithm with the greedy strategy. The search tree nodes are reduced more efficiently by searching the smallest Partial Euclidean Distance（PED） as the root node. Simulation results show that the proposed algorithm has the characteristics of low complexity and fast convergence. Compared with linear algorithms, the proposed algorithm has a 3～10 dB performance improvement when the system bit error rate is 10-4. Moreover, the algorithm reduces the complexity of the recently proposed LR-K-Best algorithm to a certain extent, and has high engineering application value.关键词：lattice reduction;massive MIMO;sphere decoding;greedy strategy
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发布时间： - 摘要：The paper experimentally demonstrates the indoor positioning in Visible Light Communication（VLC） system based on white light. The paper proposes the model of indoor positioning in VLC system and its hardware design. The paper also introduces a positioning algorithm based on the Fast Fourier Transform（FFT）. Meanwhile, we also have done the relevant experiments and get the data which has the maximum error of 14.866 cm. Experimental results show that the system can solve the indoor positioning problem.关键词：VLC;LED;visible communication indoor positioning system;microprocessor;FFT
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发布时间： - 摘要：Kramers-Kronig（KK） receiver can retrieve the phase information from the intensity information of an optical signal satisfying the minimum-phase condition. This enables KK receiver to overcome the limitation that single photodetector can only detect the intensity information of an optical signal, thus it has attracted a great deal of attention. KK receiver can compensate for the distortion due to fiber chromatic dispersion and reduce the required carrier-to-signal power ratio in an optical transmission system, significantly increasing the channel capacity and transmission distance. Since only a single-end photodetector is used, it reduces the implementation cost of a coherent optical receiver. This makes KK receiver a very promising candidate technology for the cost-sensitive intra-datacenter interconnections. However, this receiver has a couple of technical issues hindering its practicality. In this paper, the principles and applications of KK receiver, as well as its technical issues and solutions are discussed. Meanwhile, the challenges in the practical implementation of this receiver are investigated as well. Finally, the prospect of related research is discussed briefly.关键词：fiber-optic communication system;digital signal processing;optical receiver
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