硅基光子器件在光通信、光互连以及光计算领域均具有重要的作用。利用载流子色散效应,采用反向pn结构的硅基微环调制器,实现10 Gbit/s不归零码(Not Return to Zero,NRZ)信号的产生。同时,以此光调制器为核心器件,利用Optisystem和Matla...硅基光子器件在光通信、光互连以及光计算领域均具有重要的作用。利用载流子色散效应,采用反向pn结构的硅基微环调制器,实现10 Gbit/s不归零码(Not Return to Zero,NRZ)信号的产生。同时,以此光调制器为核心器件,利用Optisystem和Matlab搭建10 Gbit/s NRZ传输系统并协同仿真分析在不同光纤传输长度和驱动信号下NRZ信号的系统性能。仿真结果表明:当加载幅度为5 V方波信号时,产生调幅信号的消光比为25.2 d B,最大传输距离为22.8 km,相应的系统功率损失为7.58 d B。展开更多
As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) Modulation.It...As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) Modulation.It can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation scheme.How to design a feasible constellation is the most concerned problem of PQAM currently.This paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation scheme.Secondly,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for PQAM.Finally,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.展开更多
The paper presents a kind of reasonable structure for implementing MQAM T-TCM based on the principles of turbo codes and TCM for the first time. It can also be expanded to PSK T-TCM system, and the corresponding decod...The paper presents a kind of reasonable structure for implementing MQAM T-TCM based on the principles of turbo codes and TCM for the first time. It can also be expanded to PSK T-TCM system, and the corresponding decoding algorithm is derived. By computer simulation,its performance is analyzed. The results show that T-TCM takes the advantages of turbo codes and TCM technology, and is a kind of bandwidth-efficient coded-modulation technique obtaining high coding gain. So, in the future, T-TCM would be applied in many fields.展开更多
Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for...Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.展开更多
A dual-band bandpass microwave photonic filter(MPF) based on stimulated Brillouin scattering(SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources(TLSs) are employed to ge...A dual-band bandpass microwave photonic filter(MPF) based on stimulated Brillouin scattering(SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources(TLSs) are employed to generate two passbands by implementing phase modulation to amplitude modulation conversion by using SBS induced sideband amplification. The center frequencies of both passbands can be independently tuned ranging from 1 GHz to 19 GHz. High resolution with 3 d B bandwidth less than 30 MHz and large out-of-band rejection about 40 d B under 25 m W optical pump power are achieved.展开更多
A full-duplex optical passive access scheme is proposed and verified by simulation, in which hybrid 64/16/4-quadrature amplitude modulation(64/16/4QAM) orthogonal frequency division multiplexing(OFDM) optical signal i...A full-duplex optical passive access scheme is proposed and verified by simulation, in which hybrid 64/16/4-quadrature amplitude modulation(64/16/4QAM) orthogonal frequency division multiplexing(OFDM) optical signal is for downstream transmission and non-return-to-zero(NRZ) optical signal is for upstream transmission. In view of the transmitting and receiving process for downlink optical signal, in-phase/quadrature-phase(I/Q) modulation based on Mach-Zehnder modulator(MZM) and homodyne coherent detection technology are employed, respectively. The simulation results show that the bit error ratio(BER) less than hardware decision forward error correction(HD-FEC) threshold is successfully obtained over transmission path with 20-km-long standard single mode fiber(SSMF) for hybrid downlink modulation OFDM optical signal. In addition, by dividing the system bandwidth into several subchannels consisting of some continuous subcarriers, it is convenient for users to select different channels depending on requirements of communication.展开更多
A three-dimensional autonomous chaotic system is discussed in this paper. Some basic dynamical properties of the system, including phase portrait, Poincar′e map, power spectrum, Kaplan–Yorke dimension, Lyapunov expo...A three-dimensional autonomous chaotic system is discussed in this paper. Some basic dynamical properties of the system, including phase portrait, Poincar′e map, power spectrum, Kaplan–Yorke dimension, Lyapunov exponent spectra, signal amplitude and topological horseshoe are studied theoretically and numerically. The main finding by analysis is that the signal amplitude can be modulated via controlling the coefficients of the linear term, cross-product term and squared term simultaneously or respectively, and the phase of x3 can be modulated by the product of the coefficients of the linear term and cross-product term. Furthermore, scaling chaotic attractors of this system are achieved by modified projective synchronization with an optimization-based linear coupling method, which is safer for secure communications than the existed synchronization scheme since the scaling factors can be regarded as the security encoding key.展开更多
文摘硅基光子器件在光通信、光互连以及光计算领域均具有重要的作用。利用载流子色散效应,采用反向pn结构的硅基微环调制器,实现10 Gbit/s不归零码(Not Return to Zero,NRZ)信号的产生。同时,以此光调制器为核心器件,利用Optisystem和Matlab搭建10 Gbit/s NRZ传输系统并协同仿真分析在不同光纤传输长度和驱动信号下NRZ信号的系统性能。仿真结果表明:当加载幅度为5 V方波信号时,产生调幅信号的消光比为25.2 d B,最大传输距离为22.8 km,相应的系统功率损失为7.58 d B。
基金supported in part by the National Natural Science Foundation of China (61561039, 61271177, and 61461044)
文摘As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) Modulation.It can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation scheme.How to design a feasible constellation is the most concerned problem of PQAM currently.This paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation scheme.Secondly,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for PQAM.Finally,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.
文摘The paper presents a kind of reasonable structure for implementing MQAM T-TCM based on the principles of turbo codes and TCM for the first time. It can also be expanded to PSK T-TCM system, and the corresponding decoding algorithm is derived. By computer simulation,its performance is analyzed. The results show that T-TCM takes the advantages of turbo codes and TCM technology, and is a kind of bandwidth-efficient coded-modulation technique obtaining high coding gain. So, in the future, T-TCM would be applied in many fields.
文摘Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.
基金supported by the Science and Technology Development Plan of Jilin Province(Nos.20150204003GX and 20160519010JH)the Science and Technology Plan of Changchun(No.14KG019)
文摘A dual-band bandpass microwave photonic filter(MPF) based on stimulated Brillouin scattering(SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources(TLSs) are employed to generate two passbands by implementing phase modulation to amplitude modulation conversion by using SBS induced sideband amplification. The center frequencies of both passbands can be independently tuned ranging from 1 GHz to 19 GHz. High resolution with 3 d B bandwidth less than 30 MHz and large out-of-band rejection about 40 d B under 25 m W optical pump power are achieved.
基金supported by the National Natural Science Foundation of China(No.61107064)the Chongqing University Innovation Team Founding(No.KJTD201320)the Chongqing Science and Technology Commission Foundation(No.cstc2016jcyjA 1233)
文摘A full-duplex optical passive access scheme is proposed and verified by simulation, in which hybrid 64/16/4-quadrature amplitude modulation(64/16/4QAM) orthogonal frequency division multiplexing(OFDM) optical signal is for downstream transmission and non-return-to-zero(NRZ) optical signal is for upstream transmission. In view of the transmitting and receiving process for downlink optical signal, in-phase/quadrature-phase(I/Q) modulation based on Mach-Zehnder modulator(MZM) and homodyne coherent detection technology are employed, respectively. The simulation results show that the bit error ratio(BER) less than hardware decision forward error correction(HD-FEC) threshold is successfully obtained over transmission path with 20-km-long standard single mode fiber(SSMF) for hybrid downlink modulation OFDM optical signal. In addition, by dividing the system bandwidth into several subchannels consisting of some continuous subcarriers, it is convenient for users to select different channels depending on requirements of communication.
基金Supported by Hunan Provincial Natural Science Foundation of China under Grant No.2016JJ4036University Natural Science Foundation of Jiangsu Province under Grant No.14KJB120007the National Natural Science Foundation of China under Grant Nos.11504176and 11602084
文摘A three-dimensional autonomous chaotic system is discussed in this paper. Some basic dynamical properties of the system, including phase portrait, Poincar′e map, power spectrum, Kaplan–Yorke dimension, Lyapunov exponent spectra, signal amplitude and topological horseshoe are studied theoretically and numerically. The main finding by analysis is that the signal amplitude can be modulated via controlling the coefficients of the linear term, cross-product term and squared term simultaneously or respectively, and the phase of x3 can be modulated by the product of the coefficients of the linear term and cross-product term. Furthermore, scaling chaotic attractors of this system are achieved by modified projective synchronization with an optimization-based linear coupling method, which is safer for secure communications than the existed synchronization scheme since the scaling factors can be regarded as the security encoding key.
