最新刊期
卷 ， 期 2 ， 2018
- 摘要：All-optical chaos has been widely used in the fields of secure communication and true random number generator because of its simple structure,noise-like feature and unpredictability.In this paper,the phase effect of specific dispersion curve and the non-linear effect of internal and external laser cavity are used to flat the frequency spectrum of chaotic signals,so as to realize high-bandwidth chaotic signals and weaken the inherent correlation of chaotic signals in a certain extent.Firstly,this article builds a traditional all-optical chaotic structure and analyzes its frequency spectrum characteristics.Then,a series of specific dispersion curve generated by the dispersion compensation device is introduced into the external cavity ring of the system structure.Moreover,the impact of different dispersion curves in the frequency spectrum of chaotic signals is studied.Through the experimental results,this scheme is proved that it can broaden the frequency spectrum of the chaotic signals.关键词：all-optical chaos;true random number generator;dispersion curves;chaos frequency spectrum broadening
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发布时间： - 摘要：In order to improve the optical transmission capacity,we present a super-channel system simulation platform based on Coherent Optical Orthogonal Frequency Division Multiplexing（CO-OFDM）system with 16 Quadrature Amplitude Modulation（16 QAM）format and Dense Wavelength Division Multiplexing（DWDM）.We use Optisystem software and Matlab software for co-simulation,and adopt the nonlinear separation model to control the addition of Four Wave Mixing（FWM）noise,and measure the Bit Error Rate（BER）by the Error Vector Magnitude（EVM）.By considering the different Cyclic Prefixes（CP）,combining multiplex intervals and channels,fiber power and other factor at different bit rates,we study the impact of FWM noise and the nonlinear tolerance of the system.The simulation results show that with the increase of CP,the BER decreases first and then increases.It is also shown that the optimal value of CP is the 1/8 of the Fast Fourier Transform（FFT）window length.For new fiber-optic links,the nonlinear tolerance is better than conventional fiber links.关键词：CO-OFDM;DWDM;cyclic prefix;FWM
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发布时间： - 摘要：The software defined optical transport networks uses a centralized controller.The performance of the controller and the corresponding test methods become an important method to find the"bottleneck"of networks.The performance of the controller is evaluated and analyzed in this paper considering the"bottleneck".Then,a test method used to evaluate the long-term performance of controller is presented,which can be used to evaluate the stability and reliability of the controller in a comprehensive way.关键词：Software Defined Optical Network（SDON）;controller;performance;testing method
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发布时间： - 摘要：Chaotic signal has drawn much attention in secure communication for its characteristics of wideband,noise-like and long-term unpredictable.In this paper,chaotic optical communication is proposed to solve the secure problem of transmission in power communication network.We first study the traditional chaotic optical encryption scheme experimentally,and then investigate the secure problems of chaotic optical communication in power communication network.The scheme of time delay concealment is proposed to solve the secure problem,while the time delay concealment is experimentally demonstrated.Moreover,the security of chaotic optical communication is analyzed for parameter estimate attack,and the key space is proved to be enlarged significantly by analysis,which proves the difficulty of brute force attack,and ensures the transmission security in power communication network.关键词：chaotic optical communication;time delay concealment;security enhancement;power communication network
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发布时间： - 摘要：With the rapid development of national power grid,large-scale electric power communication network is moving into Optical Transport Network（OTN）to satisfy the management,operation and maintenance in a large number of power grid data communication.Long-distance optical communication is the characteristic of large-scale OTN,and Optical Signal Noise Ratio（OSNR）is an important parameter to measure the quality of the network.In order to ensure the efficient transmission,the calculation of OSNR is necessary to the network.This paper focuses on long-distance OTN power communication network and analyzes the characteristics of topology.The new OSNR calculation method is proposed based on the topology structure,and it’s significance and promotion value are also investigated in detail.关键词：OSNR calculation;long-distance OTN;power communication network
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发布时间： - 摘要：This paper introduces a network elements performance statistic scheme based on all kinds of communication equipment for the purpose of reducing the redundant data processing and improving the network management performance data processing efficiency.First of all,the overall block diagram and architecture of network elements performance module are discussed,which mainly consists of three parts:network management,main control and board,where we only consider the implementation of the main control in this paper.Then we describe the realization method and statistic flow of the function of network element performance.At last,we give the solution for the cases of invalid performance.The scheme studied in this paper can largely reduce the redundant performance data and significantly improve the processing efficiency.关键词：network elements performance;network management;performance data processing
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发布时间： - 摘要：In order to effectively solve the problem of time delay degradation caused by the sleep technology in the Optical Network Unit（ONU）of Time and Wavelength Division Multiplexed Passive Optical Network（TWDM-PON）,agreen dynamic bandwidth allocation algorithm based on traffic-aware is proposed.By combining energy saving mechanisms such as the receivers and transmitters sleep independently and sending sleep control signaling one by one and mixed sleep,the sleep time of transceivers are extended as long as possible,so as to reduce the energy consumption of ONU.In addition,by sensing the traffic,the bandwidth demand of services in the short future can be predicted.Therefore,the polling cycle length are dynamically adjusted according to the bandwidth demand of delay sensitive services,so as to meet the requirement of service quality and minimize the delay of expedited forwarding service at the same time.Simulation results show that the proposed algorithm can effectively reduce the energy consumption at the ONU in TWDM-PON under the premise of ensuring the quality of service.关键词：TWDM-PON;energy saving;sleep independently;delay requirement;traffic-aware
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发布时间： - 摘要：The Quality of Service（QoS）of the power dispatching data network has a significant influence on power system production management and scheduling operation.The QoS model can be presented to evaluate the operational status of the power dispatching data network.It can also measure the satisfaction of the power dispatching data network QoS requirements for grid operation.Based on the analysis of multiple QoS related concepts,we consider the interaction of multi-QoS indicators.Considering the characteristics of power dispatching data network users and power service,we build a generalized QoS model,which is user-centered and business-oriented.In the integrated QoS model,the user’s view will be integrated and the QoS of the power dispatching data network will be described with multiple viewpoints.The proposed QoS model can provide new service quality dimension for the power dispatching data network.关键词：QoS model;power dispatching data network;integrated QoS
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发布时间： - 摘要：Distributed data communication equipment has been widely used in the operator’s networking environment.The protocol stack software which is running on the equipment may run into a wrong branch,resulting in an error.Currently,when protocol stack meet a link error,it can not be quickly and effectively locate the problem without affecting other business.In this paper,this issue is analyzed and investigated,and a method of quickly querying the internal module data of the serial communication device is proposed.Based on the Linux operating system,C programming language and Python script,this method can use the command to directly view all the data in the specified data structure,which can avoid the service interruption problem caused by the traditional query protocol stack based on the breakpoint or the single step debugging method.It is shown that the work efficiency,precision and the quality of work are high,which may have the potential for further promotion.关键词：distributed data communication equipment;protocol stack software;data structure
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发布时间： - 摘要：A new type of ring photonic crystal fiber has proposed which can support 42 Orbital Angular Momentum（OAM）annular modes.The optical fiber is composed of a central air hole,an annular high refractive index layer and a cladding layer,which includes square air holes and circular air holes.We simulate and analyze the mode properties and propagation effects of OAM by finite-element analysis.The simulation results indicate that the mode index difference can be maintained above 3.45 ×10-3.Therefore,it can effectively reduce the modal coupling in the fiber with small dispersion values for all modes（the dispersion of HE2,1 is only 53.29 ps/（nm·km））.In addition,the optical energy is mainly concentrated in the high refractive index region,and the annular region does not need additional doping to obtain high refractive index.关键词：orbital angular momentum;photonic crystal fibers;effective refractive index;dispersion
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发布时间： - 摘要：In this paper,the key issues of Orbital Angular Momentum（OAM）multiplexing technologies in next generation optical communication systems is studied.Based on the theory of optical modes carrying OAM in a ring fiber,we study the influence of the ellipticity of the ring fiber on the effective refractive indices,walk-off length and model intensity profiles of the odd and even eigenmodes that form the basis of the OAM modes.Our results show that the effective refractive index difference between the odd and even modes of the same OAM mode increase with the ellipticity,thus reducing the stability of the corresponding OAM mode during propagation.Moreover,with the existence of ellipticity,the intensity profiles of the odd and even eigenmodes are distorted and the leakage of the mode field is intensified.关键词：Optical communications;orbital angular momentum;ellipticity;model walk-off
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发布时间： - 摘要：The anchor damage experiment of the submarine power cable in running is conducted in order to detect anchor damage fault using distributed optical fiber vibration sensing technology.The anchor smash and drag events are simulated using a cargo ship of 550 tons and an anchor of 1 000 kg.The 3-core optical fiber composed of submarine power cable is first monitored using distributed optical fiber vibration sensing equipment based on Ф-OTDR.The optical fiber vibration data is obtained under calm sea,anchor smash and anchor drag.The data is then analyzed in energy and FFT domain corresponding to time and space.Results indicate that the amplitude of energy spectrum and amplitude spectrum are small when the sea is calm.Anchor smash can cause a short-time energy and the amplitude increasing with abundant frequency components.Anchor drag can cause a longertime energy and amplitude increasing with less frequency components.Anchor damage fault can be detected effectively with the distributed optical fiber vibration sensing technology.关键词：distributed optical fiber vibration sensing technology;submarine power cable;anchor damage;fault detection
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发布时间： - 摘要：In order to assess whether the Reconstruction-Equivalent-Chirp（REC）technology can be adapted to a GaN laser,a405 nm wave band Distributed Feedback（DFB）semiconductor laser based on this technology is proposed.The optical performance of the designed laser in this paper is simulated and analyzed according to the transfer matrix method.The simulation results show that the designed laser has good photoelectric characteristics by using this technology.The threshold current is around 25.6 mA with a slope efficiency of 1.17 mW/mA.The single mode emission wavelength of 404.93,404.87 and404.82 nm is obtained with the injection current of 30,50 and 70 mA respectively.The side-mode suppression ratio is over40 dB in all cases.This result provides a reference for the application of this technology on GaN lasers.关键词：Semiconductor laser;distributed feedback;GaN;reconstruction-equivalent-chirp
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发布时间： - 摘要：Tunable laser has become one of the most important components in coherent optical transmission system.Based on the existing integrated tunable laser module,a novel kind of miniaturized structure to realize high stability of devices is proposed in this paper,which is fabricated on silicon photonic-wire waveguides.The external cavity of lasers based on this structure is composed of an Semiconductor Optical Amplifier（SOA）,silicon micro-ring chip and two lenses.The paper analyzes the external wave locking and chip coupling.In our proposed scheme,the double lens and Spot Size Converter（SSC）are used for coupling between SOA and silicon chip,which can greatly reduce the cavity loss,improve the output power and coupling efficiency.The lasers have shown a wide tunning range covering the C bands and the output power can reach 14 dBm.关键词：silicon micro-ring;tunable laser;coherent optical transmission
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发布时间： - 摘要：In this paper,we propose to use two Fabry-Perot（F-P）cavities as the double-edged filters to achieve the wavelength demodulation in Fiber Bragg Grating（FBG）sensor system.Since the reflected FBG signal through the two filters have different spectral characteristics and light intensities,the ratio of two intensities can be used to determine the wavelength of the measured light.Through the calculation and simulation,the system can realize the demodulation of the sensing FBG signal.The simulation results show that the system is more accurate with ideal linearity.Moreover,the system does not have mechanical movement at the time of demodulation,which means the measurement speed is faster and the running speed is more stable.关键词：double-edged filter;Fabry-Perot cavity;FBG;demodulation
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发布时间： - 摘要：Metal-Insulator-Metal（MIM）plasma waveguide systems can manipulate light at the nanoscale domain and overcome the diffraction limit,which has attracted much attention recently.In this paper,a Finite Different Time Domain（FDTD）method is used to analyze the coupling resonant characteristics of a novel MIM waveguide system.The simulation results show that the resonant wavelength of the waveguide system is smaller with larger the resonant cavity height and coupling distance in the single cavity coupling.The resonant wavelength is larger with larger resonant cavity width.In the double-cavity coupling,the peak value of the electromagnetic induced transmission decreases with the increase of distance between the cavities,and the maximum transmittance of the structure is 0.62.The electromagnetic induction effect can change the group velocity of light.The maximum optical delay of the structure is 0.14 ps.The results show that the rectangular cavity MIM waveguide system controls the propagation of light in nanoscale domain,which provides a theoretical reference for the integration of plasma nanometer devices.关键词：MIM waveguide;surface plasmons polaritons;electromagnetically induced transparency
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发布时间： - 摘要：In view of the growing Ethernet bandwidth requirements,this paper proposes a kind of 400 Gbit/s PAM4 CFP8 optical transceiver module.This paper first introduces the technical solutions and the main technical parameters in 400 Gbit/s standard.Then it describes the basic principle of PAM4 CFP8 optical transceiver module.The experiment results show good optical and electrical eye diagrams,which indicate that PAM4 CFP8 optical module is a good solution to 400 Gbit/s Ethernet transmission and may have broad application prospects in future high-speed optical communication system.关键词：400 Gbit/s Ethernet;4 pulse amplitude modulation;optical transceiver module;CFP8
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发布时间： - 摘要：Based on the selective infiltrated characteristics of Photonic Crystal Fiber（PCF）,a liquid crystal fiber optic voltage sensing structure with high sensitivity is designed.In the PCF,one air hole coated gold nano layer is used as a Surface Plasmon Resonance（SPR）channel,and the liquid crystal of E7 is used as a voltage sensitive medium to realize the detection of lower voltage.The Full vector finite Element Method（FEM）is used to simulate the characteristics of the sensing structure.The results show that the sensing sensitivity of the structure is up to 1.94 nm/V with a good linearity in the low voltage range of 050 V when the ambient temperature is 20 ℃.关键词：PCF;voltage sensing;SPR;selective infiltrated;liquid crystal
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发布时间： - 摘要：In this paper,we study the composition and characteristics of the round stains on the ferrule surfaces.The causes of the formulation are also investigated.It is found that the main composition of the round stains is tiny round droplets.The maximum radius of round stains is also defined.The result can be helpful in removing the misunderstandings on the round stains on ferrule surfaces.关键词：round stains;capillarity;round droplets;contact angle;plasma cleaning
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发布时间： - 摘要：As more devices in the Internet of Things connecting to the cellular network,the traditional LTE terminals’ protocol stack can no longer meet the demand of low power consumption and wide coverage.Based on the enhanced Machine Type Communication（eMTC）system proposed by 3 GPP in the protocol,the paper studies the paging and measurement of the extended Discontinuous Reception（eDRX）of the eMTC system in terminal side.We also propose the Layer 1-Control（L1 C）and design the procedure of paging and measurement.Finally,we use Visual Studio and Extensible Markup Language（XML）to verify the rationality and feasibility of the design.关键词：protocol stack;extended discontinuous reception;layer-1 control;extensible markup language
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发布时间： - 摘要：In the wavelet threshold denoising,it is important to choose the threshold.In order to overcome the shortcomings of traditional fixed thresholds on each scale,a new wavelet threshold denoising method is proposed in this paper.The improved threshold can be changed with the number of decomposed layers,as it is shown flexibility in practice situation.In this paper,Signal Noise Ratio（SNR）and Mean Square Error（MSE）are used as the parameters to evaluate the denoising performance.Compared with the traditional threshold,the simulation results show that the denoising effect based on the improved wavelet threshold denoising method is better than the traditional wavelet denoising based on sqtwolog,rigrsure,heursure and minimaxi wavelet threshold.The improved wavelet threshold denoising method has a high practical value.关键词：wavelet threshold denoising;threshold;SNR;MSE
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