The higher peak-to-average power ratio(PAPR) is a major shortcoming of coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems. Selective mapping(SLM) technology can effectively reduce the probabi...The higher peak-to-average power ratio(PAPR) is a major shortcoming of coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems. Selective mapping(SLM) technology can effectively reduce the probability of high PAPR, but it has higher computational complexity, and requires additional bandwidth to transmit the side information, which will affect the transmission efficiency of the system. In response to these shortcomings, a novel improved SLM(NI-SLM) scheme with low complexity and without side information is proposed. Simulation results show that the proposed scheme can exponentially reduce the computational complexity, and the bit error rate(BER) performance can greatly approach the original signal. What's more, it shows the better PAPR reduction performance.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 novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication(3G) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder modulator(MZM) is pr...A novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication(3G) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder modulator(MZM) is proposed.There is no apparent nonlinearity induced by the ROF system.By employing this analog ROF signal transmission technique,highly transparent fiber-wireless convergence networks can be realized,which are ideal for multi-standard wireless system operation.展开更多
A cross-shaped photonic crystal waveguide formed by a square lattice Al_2O_3 rods array is numerically and experimentally investigated. The band gap of the TE mode for the photonic crystals and transmission characteri...A cross-shaped photonic crystal waveguide formed by a square lattice Al_2O_3 rods array is numerically and experimentally investigated. The band gap of the TE mode for the photonic crystals and transmission characteristics of waveguides are calculated by the plane wave expansion method and the finite element method.We perform the experiments in the microwave regime to validate the numerical results. The measured reflection and transmission characteristics of the photonic crystals show a large band gap between 8.62 and 11.554 GHz（relative bandwidth is 29.34%）. The electromagnetic waves are transmitted stably in the waveguides, and the transmission characteristics maintain a high level in the band gap.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61472464,61671091 and 61471075)the Natural Science Foundation of Chongqing Science and Technology Commission(No.cstc2015jcyj A0554)
文摘The higher peak-to-average power ratio(PAPR) is a major shortcoming of coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems. Selective mapping(SLM) technology can effectively reduce the probability of high PAPR, but it has higher computational complexity, and requires additional bandwidth to transmit the side information, which will affect the transmission efficiency of the system. In response to these shortcomings, a novel improved SLM(NI-SLM) scheme with low complexity and without side information is proposed. Simulation results show that the proposed scheme can exponentially reduce the computational complexity, and the bit error rate(BER) performance can greatly approach the original signal. What's more, it shows the better PAPR reduction performance.
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 the National Natural Science Foundation of China(No.61371061)the Zhejiang Provincial Natural Science Foundation of China(Nos.LY12F01010 and LQ13F010007)the Open Fund of the Information and Communication Engineering of Top Key Discipline of Zhejiang Province
文摘A novel radio-over-fiber(ROF) scheme to simultaneously generate and transmit the 3rd generation telecommunication(3G) and millimeter-wave(MMW) signals by using a single dual-electrode Mach-Zehnder modulator(MZM) is proposed.There is no apparent nonlinearity induced by the ROF system.By employing this analog ROF signal transmission technique,highly transparent fiber-wireless convergence networks can be realized,which are ideal for multi-standard wireless system operation.
基金supported by the National Natural Science Foundation of China under Grant No.61171006
文摘A cross-shaped photonic crystal waveguide formed by a square lattice Al_2O_3 rods array is numerically and experimentally investigated. The band gap of the TE mode for the photonic crystals and transmission characteristics of waveguides are calculated by the plane wave expansion method and the finite element method.We perform the experiments in the microwave regime to validate the numerical results. The measured reflection and transmission characteristics of the photonic crystals show a large band gap between 8.62 and 11.554 GHz（relative bandwidth is 29.34%）. The electromagnetic waves are transmitted stably in the waveguides, and the transmission characteristics maintain a high level in the band gap.
