最新刊期
卷 ， 期 1 ， 2017
- 摘要：In order to improve the stability of a single-mode laser system,the power spectrum in single-mode laser loss model is calculated based on the linear approximation method after inputting a biased amplitude modulation signal.The change rules of are obtained when the modulation signal of low frequency and cross-correlation between the real and imaginary part of the quantum noise are varied.The results indicate that when the low frequency of the modulation signal is large,the quantum noise is large,the self-saturation coefficient is small,and the cross-correlation between the real and imaginary part of the quantum noise is stronger,the power of the system is small and the stability of a single-mode laser system is better.Meanwhile,it is found that the amplitude of carrier signal has a significant influence on the power spectrum of the laser system.关键词：laser physics;amplitude modulation wave;single-mode laser;power spectrum;linear approximation method
- 5
- |
- 84
- |
- 1
发布时间： - 摘要：The channel estimation for hybrid Power Line Communication（PLC）& Visible Light Communication（VLC）system based on Orthogonal Frequency Division Multiplexing（OFDM）is investigated.We first introduce a hybrid communication system with PLC and VLC channel models.Then we study two kinds of pilot structure of block type and comb type,two estimation criterions of Least Squares（LS）and Singular Value Decomposition（SVD）,and two interpolation methods of linear interpolation and Discrete Fourier Transform（DFT）-based interpolation.It is shown that SVD combined with linear interpolation is more appropriate to hybrid PLC & VLC system,which has the best performance and is insensitive to pilot space.关键词：OFDM;PLC;VLC;channel estimation
- 8
- |
- 121
- |
- 2
发布时间： - 摘要：As optical networks evolve toward Software Defined Optical Networks（SDON）with higher speed and greater capacity,the scale of optical networks is also enlarged increasingly,which leads to the longer lightpath and accumulated optical signal degradation problems.In order to solve this problem,this paper proposes a Optical Signal Noise Rate（OSNR）awareness based lightpath optimization scheme in OpenFlow enabled SDON.This proposed scheme is able to take the OSNR factor into consideration and introduce OSNR factor into the lightpath establishment and wavelength allocation.Thus,the communication blocking due to low OSNR value can be avoided.Simulation results show that the proposed scheme can achieve better performance on successive rate of lightpath establishment under non-ideal networks.关键词：SDON;OpenFlow software;OSNR;lightpath optimization
- 5
- |
- 59
- |
- 5
发布时间： - 摘要：Current intelligent optical networks can not actively deal with failure in network.Aimed to improve the survivability of intelligent optical network,this paper proposes a Bayesian model based active fault alarm mechanism in intelligent optical network.The proposed mechanism is able to judge of potential failure in advance with high accuracy and to reduce the false-alarm efficiently.Using different stylebooks and their corresponding algorithms,the fault prediction probability is rational estimated through reasoning,which builds a rational Bayesian model for active fault alarm.Simulation results show that this proposed approach can greatly improve the survivability ability of intelligent optical networks,in terms of connection recovery time and resources utilization rate.关键词：active fault alarm;Bayesian model;intelligent optical networks;survivability
- 3
- |
- 123
- |
- 4
发布时间： - 摘要：In order to solve the problem of the label maintenance and management for the ring protection based on G.8132 protocol and the Wrapping protection mechanism,an improvement ring protection program is proposed.The pathway creation of ring protection and the switching mechanism are introduced,as well as the architecture of function modules.The switching time of the ring protection is tested.It turned out to be that the switching time of the ring protection mechanism could meet the requirements of 50 ms on the engineering application.Therefore,it can provide effective network-level protection for bearer service of the Packet Transport Network（PTN）.关键词：the ring protection;G.8132 protocol;protection mechanism;PTN
- 3
- |
- 75
- |
- 4
发布时间： - 摘要：An algorithm to remove the modulated phase is further investigated to make the algorithm be suitable for the coherent systems of higher-order modulation format.In the algorithm,the absolute operation is respectively implemented on the real part and imaginary part of received complex signals to remove their modulated phases.The performance of the proposed algorithm in a 28 GBaud coherent 64 ary Quadrature Amplitude Modulation（64QAM）system is investigated through simulation.The simulation results show that the proposed algorithm requires no multiplier and reaches the approximate performance as the Mth-power operation in the frequency offset estimation.Therefore,the algorithm reduces the complexity with similar performance compared with Mth-power operation.关键词：coherent optical communication;frequency offset estimation;Mth-power operation;modulated phase removal
- 3
- |
- 54
- |
- 1
发布时间： - 摘要：A Frequency Offset Estimation（FOE）algorithm based on multi-steps interpolations is proposed for coherent optical systems.Firstly,the proposed algorithm implements Fast Fourier Transform（FFT）operation with a small number of samples to obtain the coarse FOE.Then,it adopts Discrete Fourier Transform（DFT）to reduce the computational complexity.In a 28 GBaud coherent Quaternary Phase-Shift Keying（QPSK）system,compared with Least-Squares（LS）FOE algorithm,the proposed algorithm can significantly reduces the complexity.关键词：coherent optical communication;frequency offset estimation;FFT;multi-steps interpolation
- 3
- |
- 99
- |
- 2
发布时间： - 摘要：Burst rogue ONU is one type of the upstream uncontrolled optical signal interference in the PON system,which is difficult to locate because of the randomness and the duration of the fault.This paper describes the behaviors and possible causes of burst interference and summarizes the typical protection methods.Then several typical protection methods to the burst type always-on faults are compared.Furthermore,several methods to locate the burst rogue ONU are discussed.Finally,a method of eliminating faults is introduced.关键词：PON;ONU;interference;burst type always-on
- 4
- |
- 50
- |
- 0
发布时间： - 摘要：In this paper,the research progress of high-end optical fiber technology in our country is analyzed and summarized.The high-end optical fiber technologies for 400Gbit/s system include ultra-low-loss optical fiber and large-effective-area optical fiber.In China,the attenuation for ultra-low-loss optical fiber has achieved 0.167dB/km,which has reached the international advanced level.The effective area at wavelength of 1 550 nm for large-effective-area optical fiber has achieved 130μm2,which has a certain gap compared with the international level of 150μm2.Based on the research of Tbit/s large capacity Space-Division-Multiplexing（SDM）optical fiber,the basic researches of the multi-core optical fiber and Orbital Angular Momentum（OAM）fiber are carried out and have achieved great progress.The research results show that the high-end optical fiber technologies for large-capacity optical communication have reached the international advanced level,which bring a new possibility for the next generation of high-speed optical fiber communication technology.关键词：high-end optical fiber;ultra-low-loss fiber;large-effective-area fiber;400 Gbit/s system;SDM
- 4
- |
- 289
- |
- 7
发布时间： - 摘要：In order to realize hybrid arithmetic functions（2θA-θB、2θB-θA）of phase-modulated signals,we describe the operating principle of optical phase inter-modulation in degenerate Four-Wave Mixing（FWM）process,and present the analytic solution of the degenerate FWM equations in the pump depletion case.A typical hybrid arithmetic scheme using highly nonlinear fiber is studied in detail.As an example,the influence of input amplitude noise on the hybrid arithmetic calculator for two quaternary signals is analyzed.It is shown that the calculator has an optical noise figure or Optical Signal-to-Noise Ratio（OSNR）degradation of about 6.6dB.It is also indicated that the input OSNR should be more than about 25 dB for a symbol-error rate of≤10-3,corresponding to the Error Vector Magnitude（EVM）smaller than 22%.关键词：all-optical signal processing;FWM;phase modulation;noise performance;optical communication
- 3
- |
- 59
- |
- 0
发布时间： - 摘要：The ZnMgO/ZnO ultraviolet band Distributed Feedback（DFB）semiconductor laser is simulated and designed by using the Transfer Matrix Method（TMM）.A peak wavelength of 364.8nm is obtained when the duty cycle is 0.5,the grating period is 92.5nm,and the height of the grating is 65 nm.By changing the thickness of active layer,the influence of different active layer thickness on the performance of the laser is analyzed.The numerical simulation results indicate that when increasing the thickness of the active layer,the threshold current is increased as the limitation on the carrier is weakened.When reducing the thickness of the active layer,the limiting effect of the waveguide layer on the photon decreases,which result in a higher threshold current and a lower output power.Therefore,the proper selection of active layer thickness can improve the performance of DFB laser.关键词：DFB semiconductor laser;ZnMgO/ZnO;Bragg gratings;ultraviolet band
- 4
- |
- 99
- |
- 1
发布时间： - 摘要：The design approach of the transmission filter using the subwavelength metal waveguide grating with narrow grooves is proposed.The operational principle of the filter is that its low transmission background is obtained by using the metal grating with narrow grooves,and its transmission peak is achieved by using the hybrid Guided-Mode Resonance（GMR）and the Surface Plasmon Polariton（SPP）resonances.It is shown that by increasing the thickness of the waveguide layer,a dual-channel transmission filter with good filtering performance can be obtained based on the hybrid modes of multiorder GMR and SPP resonances.The transmission peaks of the dual-channels at 1 412 nm and 1 653 nm are 72.1% and 63.6%,respectively.Further analysis show that the peak transmission and its location of the filter at longer wavelength is mainly affected by the grating thickness.This is because that the energy of the magnetic field of the longer wavelength is mainly confined in the grating layer.For the transmission peak of the filter at the shorter wavelength,the energy of the magnetic field is mainly confined in the waveguide.Therefore,the shift of the transmission peak is sensitive to the variation of the waveguide thickness.关键词：narrow grooves;metal waveguide grating;subwavelength structure;transmission filter
- 3
- |
- 119
- |
- 0
发布时间： - 摘要：High power requirements of the traveling wave photodetector array increase the structure complexity and reduce the response speed.In order to solve this problem,a kind of improved Traveling-Wave Detector Arrays（TWDA）structure based on diode groups is proposed.The power synthesis,frequency response and return loss of traveling-wave photodiode arrays are compared and analyzed.Under the condition of same amount of diode,the improved TWDA structure uses less inductive element with constant output power and the working bandwidth,and much smaller return loss.The research results show that the improved structure can streamline the structure of the original circuit while improving its response speed and circuit matching performance with better satisfying the requirements of power.关键词：traveling-wave detector arrays;power combining;return loss;response speed;radio-over-fiber
- 5
- |
- 70
- |
- 4
发布时间： - 摘要：Considering the property that magnetic permeability of the ferrite material changes under the control of an external magnetic field,a novel scheme of THz routing optical switch and beam splitter,based on two-dimensional magnetic photonic crystals,is proposed.Theoretical analysis and numerical simulation is conducted by Plane Wave Method（PWM）and FiniteDifference Time-Domain（FDTD）.The results show that,the insertion loss of the routing optical switch is 0.017 dB,the extinction ratio is 26.97 dB,and the maximum stability time is 25.3ps.Moreover,the additional loss of the beam splitter is only0.07 dB,and the splitting ratio is nearly 1∶1.The routing optical switch and beam splitter are achieved by using these two-dimensional magnetic photonic crystals,which have important application prospect in future integrated optical circuit.关键词：routing switch;beam splitter;THz wave;magnetic photonic crystal
- 3
- |
- 152
- |
- 5
发布时间： - 摘要：To improve the low sensitivity of current gas sensors,an infrared light sensor system was designed using black silicon for radiation layer with amplify circuit and controller chip.We first introduce the fabrication and simulation of infrared light source.A new type of nano material black silicon was presented which can increase the light radiation efficiency by 40%.Then the peripheral circuit design of the sensor system was presented,including the power drive circuit,the two-stage filter amplifier circuit and the central processing unit.The test results show that the system could effectively enhance the sensitivity of gas sensors and meet the design requirements.关键词：black silicon;radiation layer;infrared light;gas sensor
- 3
- |
- 113
- |
- 1
发布时间： - 摘要：In order to investigate the modulation phenomenon of pulse in the time domain and determine its frequency spectrum,an Optical Parametric Amplification-Frequency-Resolved Optical Gating（OPA-FROG）measurement scheme for optical arbitrary waveforms based on optical parametric amplification of crystal is presented in this paper.The program structure is simple and easy to implement.In the MATLAB environment,we use the Principal Component Generalized Projects（PCGP）algorithm to recovery the waveform.The results show that the scheme can achieve an accurate measurement of the amplitude and phase of arbitrary optical waveform.The characteristics of gating process of the gate pulse with gain amplification can realize the measurement of weak signals.关键词：OPA;FROG;optical arbitrary waveform measurement;PCGP algorithm
- 3
- |
- 76
- |
- 2
发布时间： - 摘要：For solving the problem of the collision between tags in Radio Frequency Identification（RFID）system,many anti-collision algorithms have been proposed.One of the efficient anti-collision algorithms is Dynamic Framed Slotted ALOHA（DFSA）algorithm.This paper studies the optimal frame size of EDFSA and proposes a new algorithm considering tags,which can be identified by a reader when special collision exists in some situation by using Manchester code.Mathematical analysis and simulation result shows that this algorithm is more efficient than DFSA.关键词：RFID;anti-collision;DFSA
- 4
- |
- 121
- |
- 5
发布时间： - 摘要：In order to suppress the third-order intermodulation distortion of microwave photonic link and increase its spuriousfree dynamic range,a microwave photonic link based on phase modulation is proposed,which has a large dynamic range without chromatic dispersion.The third-order intermodulation distortion is suppressed by using two axis of phase modulator and addition of two-way signals whose phase difference betweenπ.In addition,due to the single-sideband signal after the linearization,the chromatic dispersion is also suppressed.The simulation results show that the spurious-free dynamic range of the proposed microwave photonic link is increased by 19.5dB,comparing with the conventional one.关键词：microwave photonic link;phase modulation;spurious-free dynamic range
- 3
- |
- 119
- |
- 1
发布时间： - 摘要：Spatial Modulation（SM）is a novel multi-antenna transmission scheme,which originally constitutes a mapping relation between inputting bits and transmitting antenna.Due to the fact that the Maximum Likelihood（ML）optimal detection algorithm of SM system requires traversing all possible codebook,the algorithm suffers high detection complexity.For this reason,some people have proposed simplified algorithms,such as MF,sphere decoding algorithm.Different from these algorithms,this paper combines EMF algorithm and NMF algorithm.We add candidate set factor Tto effectively balance the system performance and complexity.Simulation results show that when T =4,the improved MF detection algorithm can achieve similar performance as EMF algorithm,but with lower computational complexity.关键词：spatial modulation;signal detection;maximum likelihood;matched filtering
- 3
- |
- 111
- |
- 7
发布时间： - 摘要：Based on the SLM algorithm,an improved algorithm is proposed to reduce the Peak to Average Power Ratio（PAPR）in the Visible Light Communication（VLC）system.Using improved Logistic chaotic sequence as superimposed training sequence,and the random phase sequences in this algorithm,the system doesn’t need to transfer all the random phase sequences,which only need to transfer the initial value of chaotic sequence.At the receiver side,the chaotic sequences can be recovered according to the initial value.Therefore,this algorithm can reduce the redundancy of the side band information and improve the bandwidth utilization rate and BER performance of the system.The principle of the algorithm and simulation results are given in this paper.The simulation results show that the new algorithm can effectively suppress the PAPR of the VLC system,and improve the SNR of the system.关键词：optical communication;LED;OFDM;PAPR
- 4
- |
- 197
- |
- 5
发布时间： - 摘要：Currently,white LED is widely used in lighting.Simultaneously,it has also achieved success in the area of Visible Light Communication（VLC）technology.In this paper,a short distance transmission system is designed by using white LED as the signal transmission medium.Pulse Width Modulation（PWM）is applied to modulate the audio signal and the ambient temperature signal.At the receiver side,current feedback circuit and the voltage amplification circuit are utilized to enhance the dynamic range of the PWM wave peak value.Then we use STM32 to demodulate the optical pulses.We also use Time-Division Multiplexing（TDM）technology to realize the real-time short-distance transmission of audio signals and digital signals from 300 to 3400Hz.The results show that the waveform has no obvious distortion on the oscilloscope after the transmission.关键词：VLC;PWM;STM32;audio signal;TDM
- 3
- |
- 332
- |
- 3
发布时间： - 摘要：The application of traditional positioning technology is limited because of the particularity of indoor environment.In order to solve indoor positioning problem,a scheme of indoor visible light beacon positioning based on Smartphone is proposed.In this scheme,locater beacons are sent out by indoor Light Emitting Diode（LED）light source and the visible light signal is received by exploiting rolling shutter effect of the camera embedded in Smartphone.Indoor visible light positioning is realized by the information in locator beacon which is extracted by the image processing algorithm in Smartphone application.The result of experiments is verified to be feasibility and effectiveness in this scheme.关键词：visible light communication;Smartphone;beacon positioning;rolling shutter
- 5
- |
- 484
- |
- 15
发布时间： - 摘要：Based on the principle of Visible Light Communication（VLC）technology,we design a portable antenna light equipment,which has the advantages of large bandwidth,high security,no electromagnetic radiation pollution,etc.The device uplink and downlink use a 1 W white Light-Emitting Diode（LED）as an emission source,which can meet the needs of lighting and communications.We also designed transmitter circuits and high-sensitivity receiver circuits,and data transmission,which is based on the Manchester encoding and decoding process and dramatically improves the sensitivity of the reception end.Using Universal Asynchronous Receiver/Transmitter（UART）send and receive data,we demonstrate a transfer rate of 115.2kbit/s and 3mfull-duplex data transmission experiment,which satisfy the requirement of the electromagnetic radiation sensitive occasions for short-range demand low speed communication.关键词：LED;VLC;portable antenna
- 3
- |
- 146
- |
- 6
发布时间：
- Postal code：430205
- Technical support is provided by Beijing Founder electronics co., LTD 鄂ICP备2022010197
鄂公网安备 42011202002092号 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
- Total Visits：75845
0