Low-cost,flexible and intelligent optical performance monitoring and management is a key enabling technology for network quality guarantee,especially in the era of explosive growth of communication capacity and networ...Low-cost,flexible and intelligent optical performance monitoring and management is a key enabling technology for network quality guarantee,especially in the era of explosive growth of communication capacity and network scale.However,to the best of our knowledge,it is extremely challenging to implement real-time performance monitoring and operations,administration and maintenance(OAM) in a highly complex dynamic network.In this paper,we propose an innovative optical identification(OID) scheme that can realize both performance monitoring and some advanced OAM sub-functions.The basic concepts,applications,challenges and evolution directions of this OID tool are also discussed.展开更多
<div style="text-align:justify;"> In order to meet the needs of the rapid development of optical fiber communication technology, combined with the thinking of the Internet of Things, a new idea of desi...<div style="text-align:justify;"> In order to meet the needs of the rapid development of optical fiber communication technology, combined with the thinking of the Internet of Things, a new idea of designing an optical fiber test equipment using Raspberry Pi is proposed. At the same time, the design of a multi-parameter measuring device for optical fiber signals based on Flask was completed. </div>展开更多
In this paper, we describe a novel technique based on the flipped-exponential (FE) Nyquist pulse method for reducing peak-to-average power ratio (PAPR) in an optical direct-detection orthogonal frequency-division ...In this paper, we describe a novel technique based on the flipped-exponential (FE) Nyquist pulse method for reducing peak-to-average power ratio (PAPR) in an optical direct-detection orthogonal frequency-division multiplexing (DD-QFDM) system, The technique involves proper selection of the FE Nyquist pulses for shaping the different subcarriers of the OFDM. We apply this technique to a DD-OFDM transmission system to significantly reduce PAPR. We also investigate the sensitivity of a received OFDM signal with strong nonlinearity in a standard single-mode fiber (SMF).展开更多
The operational parameters including the polarization controlling and the pump power in a nonlinear polarization rotation-based passively mode-locked fiber laser are studied in this paper.The carrier rate equations of...The operational parameters including the polarization controlling and the pump power in a nonlinear polarization rotation-based passively mode-locked fiber laser are studied in this paper.The carrier rate equations of the activated erbium-doped fiber are first employed together with the nonlinear Shro¨dinger equations to reveal the relation between the operational parameters and the output state of the passively mode-locked fiber laser.The numerical and experimental results demonstrate that the output state of the mode-locked laser varies with the polarization controlling and the pump power.The periodicity of the polarization controlling is observed.With given pump power,there exists a set of polarization controlling under which the ultra-short pulse can be generated.With given polarization controlling,the mode-locked state can be maintained generally except for some particular values of pump power.Three shapes of the output optical spectra from the fiber cavity can be identified when the pump power changes.The results in this paper provide a comprehensive insight into the operation of the nonlinear polarization rotation-based passively mode-locked fiber laser.展开更多
In this paper, the transceiver performance of optical 64QAM-OFDM signals with different sub-car- riers is studied. Firstly, we build a 40Gbit/s optical coherent 64QAM-OFDM transmission system. 64QAM-OFDM optical signa...In this paper, the transceiver performance of optical 64QAM-OFDM signals with different sub-car- riers is studied. Firstly, we build a 40Gbit/s optical coherent 64QAM-OFDM transmission system. 64QAM-OFDM optical signals with 16, 32, 64, 64, 128, 256 and 512 sub-carriers are transmitted over 100 km single mode fiber (SMF). Then, the optical spectrum diagrams before and after transmission, the bit error rate (BER) and constellation diagrams of received signals were compared. The simulation results show that, with the number of sub-carriers increasing, the value of PAPR will gradually increase and the quality of the received optical signals will deteriorate. Moreover, with the number of sub-carriers increasing, the computational complexity will increase when digital signal processing (DSP) is used. Therefore, we should choose the optimal number of sub-carriers, and the PAPR influence and BER are also considered for achieving effective transmission.展开更多
A CWDM is proposed for fiber optic communication networks. The OADM is designed based on SOI structure. The scheme for CWDM optical signal protection is presented.
With the continuous development of automotive intelligent networking and autonomous driving technologies,the number of in-vehicle electronic systems and applications is increasing rapidly.This change increases the amo...With the continuous development of automotive intelligent networking and autonomous driving technologies,the number of in-vehicle electronic systems and applications is increasing rapidly.This change increases the amount of data to be transmitted in the vehicle and puts forward further requirements of higher speed and safety for in-vehicle communication.Traditional vehicle bus technologies are no longer sufficient to meet today’s high-speed transmission requirements,in which copper cables are used extensively,resulting in serious electromagnetic interference(EMI).Vehicle optical fiber communication technology,besides greatly improving the data transmission rate,has the advantages of anti-EMI,reducing cable space and vehicle mass.This paper first presents the motivation of applying vehicle optical fiber communication technology and reviews the development history of vehicle optical fiber communication technology.Then,the paper researches the devel-opment trend of automotive electrical and electronic architecture(EEA),from distributed EEA to domain centralized EEA and zone-oriented EEA.Based on the discussion of the development trend of automotive EEA,an EEA based on vehicle optical fiber communication technology is proposed.Finally,the key points and future directions of vehicle optical fiber communication technology research are highlighted,including vehicle multi-mode optical fiber technology,vehicle optical fiber network protocol,and topology.展开更多
We experimentally transmit eight wavelength-division-multiplexing(WDM)channels,16 quadratic-amplitude-modulation(QAM)signals at 32-GBaud,over 1000 km few mode fiber(FMF).In this experiment,we use WDM,mode division mul...We experimentally transmit eight wavelength-division-multiplexing(WDM)channels,16 quadratic-amplitude-modulation(QAM)signals at 32-GBaud,over 1000 km few mode fiber(FMF).In this experiment,we use WDM,mode division multiplexing,and polarization multiplexing for signal transmission.Through the multiple-input-multiple-output(MIMO)equalization algorithms,we achieve the total line transmission rate of 4.096 Tbit/s.The results prove that the bit error rates(BERs)for the16QAM signals after 1000 km FMF transmission are below the soft-decision forward-error-correction(SD-FEC)threshold of2.4×10^(-2),and the net rate reaches 3.413 Tbit/s.Our proposed system provides a reference for the future development of high-capacity communication.展开更多
Optical networks are evolving toward ultrawide bandwidth and autonomous operation.In this scenario,it is crucial to accurately model and control optical power evolutions(OPEs)through optical amplifiers(OAs),as they di...Optical networks are evolving toward ultrawide bandwidth and autonomous operation.In this scenario,it is crucial to accurately model and control optical power evolutions(OPEs)through optical amplifiers(OAs),as they directly affect the signal-to-noise ratio and fiber nonlinearities.However,a fundamental contradiction arises between the complex physical phenomena in optical transmission and the required precision in network control.Traditional theoretical methods underperform due to ideal assumptions,while data-driven approaches entail exorbitant costs associated with acquiring massive amounts of data to achieve the desired level of accuracy.In this work,we propose a Bayesian inference framework(BIF)to construct the digital twin of OAs and control OPE in a data-efficient manner.Only the informative data are collected to balance the exploration and exploitation of the data space,thus enabling efficient autonomous-driving optical networks(ADONs).Simulations and experiments demonstrate that the BIF can reduce the data size for modeling erbium-doped fiber amplifiers by 80%and Raman amplifiers by 60%.Within 30 iterations,the optimal controlling performance can be achieved to realize target signal/gain profiles in links with different types of OAs.The results show that the BIF paves the way to accurately model and control OPE for future ADONs.展开更多
An optical PPM CDMA communication system with an optical hard limiter in front of the correlator of a receiver is proposed in order to reduce multi user interference. The performance of the system is evaluated ...An optical PPM CDMA communication system with an optical hard limiter in front of the correlator of a receiver is proposed in order to reduce multi user interference. The performance of the system is evaluated when the effects of both multi user interference and photo detector shot noise are considered. An upper bound on the bit error rate is derived. The comparison of the performance of the above receiver with that of the optical PPM CDMA system without an optical hard limiter is made. Simulation results show that the performance of the system with an optical hard limiter is superior to that of the conventional one.展开更多
As the emergence of various highbandwidth services and the requirements to support 5G/Wi-Fi 6 wireless networks,the next generation fixed networks,i.e.F5G,are expected to be realized in the 5G era.F5G is endowed with ...As the emergence of various highbandwidth services and the requirements to support 5G/Wi-Fi 6 wireless networks,the next generation fixed networks,i.e.F5G,are expected to be realized in the 5G era.F5G is endowed with new characteristics,including ultra-high bandwidth,all-optical connections and optimal service experience.With the prospect of optical-to-everywhere,optical technologies are used for mobile front-haul,mid-haul,and back-haul.Optical access networks would play an important role in F5G to support radio access network and fixed access network.Low-latency PON is a key for cost effective-haul traffic aggregation.In terms of signal transmission,intensity modulation directdetection(IM-DD)is a promising scheme due to its simple architecture.The fundamental challenge associated with direct-detection is the disappearance of the transmitted signal’s phase.In access network,the flexibility and low latency are the two key factors affecting service experience.In this article,we review the evolution of PONs and the challenges of current PONs in detail.We analyze key enabling digital signal processing(DSP)techniques,including detection linearization for direct-detection and simplified coherent detection,adaptive equalizers,digital filer enabled flexible access network and low-latency inter-ONU communications.Finally,we discuss the developing trends of future optical access networks.展开更多
This paper begins with Nyquist wavelengthdivision multiplexing (WDM) and then introduces fasterthanNyquist. In fasterthanNyquist a certain amount of intersymbol interference (ISI) is accepted, which violates the f...This paper begins with Nyquist wavelengthdivision multiplexing (WDM) and then introduces fasterthanNyquist. In fasterthanNyquist a certain amount of intersymbol interference (ISI) is accepted, which violates the fundamental principle of Nyquist WDM. This results in muchrelaxed transceiver bandwidth and simpler spectral design. However, in fasterthanNyquist, implementation complexity is shifted from the transmitter side to the receiver side. Therefore, successful application of fasterthanNyquist depends on innovation in the receiver structure. In this paper, we discuss the guidelines for implementing suboptimum, lowcomplexity receivers based on fasterthanNyquist. We suggest that duobinary shaping is a good technique for trading off achievable spectral efficiency, detection performance, and implementation complexity and might be preferable to Nyquist WDM. Experiments are conducted to verify robustness of the proposed technique.展开更多
An equivalent noise model of optical receiver amplifiers as shown in Fig.1 has been given in many fiber optical communication literatures. It is proved in this paper that this equivalent noise model is neither equiva...An equivalent noise model of optical receiver amplifiers as shown in Fig.1 has been given in many fiber optical communication literatures. It is proved in this paper that this equivalent noise model is neither equivalent to the original one nor measurable. The main reason is that the position of the input impedance in this noise model is not the same with its in the typical noise model,but the same S vn , S in with the typical noise model are used. So the equivalent noise model above is wrong and is not fit to be taken into application.展开更多
In quantum noise stream cipher(QNSC)systems,it is difficult to compensate fiber nonlinearity by digital signal processing(DSP)due to interactions between chromatic dispersion(CD),amplified spontaneous emission(ASE)noi...In quantum noise stream cipher(QNSC)systems,it is difficult to compensate fiber nonlinearity by digital signal processing(DSP)due to interactions between chromatic dispersion(CD),amplified spontaneous emission(ASE)noise from erbiumdoped fiber amplifier(EDFA)and Kerr nonlinearity.Nonlinearity equalizer(NLE)based on machine learning(ML)algorithms have been extensively studied.However,most NLE based on supervised ML algorithms have high training overhead and computation complexity.In addition,the performance of these algorithms have a lot of randomness.This paper proposes two clustering algorithms based on Fuzzylogic C-Means Clustering(FLC)to compensate the fiber nonlinearity in quadrature amplitude modulation(QAM)-based QNSC system,including FLC based on subtractive clustering(SC)and annealing evolution(AE)algorithm.The performance of FLC-SC and FLC-AE are evaluated through simulation and experiment.The proposed algorithms can promptly obtain suitable initial centroids and choose optimal initial centroids of the clusters to achieve the global optimal initial centroids especially for high order modulation scheme.In the simulation,different parameter configurations are considered,including fiber length,optical signal-to-noise ratio(OSNR),clipping ratio and resolution of digital to analog converter(DAC).Further-more,we measure the Q-factor of transmission signal with different launched powers,DAC resolution and laser linewidth in the optical back-to-back(BTB)experiment with 80-km single mode fiber.Both simulation and experimental results show that the proposed techniques can greatly mitigate the signal impairments.展开更多
In this paper the expression of the output pulse Stokes vector is derived based on the Jones matrix model proposed by A.Orlandini et al. The basic properties of degree of polarization (DOP) for output pulse are invest...In this paper the expression of the output pulse Stokes vector is derived based on the Jones matrix model proposed by A.Orlandini et al. The basic properties of degree of polarization (DOP) for output pulse are investigated.展开更多
In this paper,we propose and experimentally demonstrate a joint shaping technique to improve the performance of a lowresolution transmission system for the first time,to the best of our knowledge.The joint shaping tec...In this paper,we propose and experimentally demonstrate a joint shaping technique to improve the performance of a lowresolution transmission system for the first time,to the best of our knowledge.The joint shaping technique combines probabilistic shaping(PS)and error feedback noise shaping(EFNS).In the 40-Gbaud intensity-modulation direct-detection(IM/DD)experimental transmission system,a bit-error-rate(BER)of 3.8×10^(-3)can be achieved easily with the joint shaping at the physical number of bits(PNOB)of 3.In the 30-Gbaud dual polarization(DP)coherent experimental transmission system,a BER below 1×10^(-3)is easily obtained with a 3-bit quantizer by using joint shaping.The optimization of the shaping degree is also analyzed.展开更多
F, K, 1) Optical orthogonal codes (OOC) are the best address codes applied to optical code division multiple access (OCDMA) communication systems, but the construction of the codes is very complex. In this paper, a me...F, K, 1) Optical orthogonal codes (OOC) are the best address codes applied to optical code division multiple access (OCDMA) communication systems, but the construction of the codes is very complex. In this paper, a method of construction of the OOC from block design is discussed and a method of computer aid design is presented, by which we can construct desired (F, K, 1) OOC easily.展开更多
We propose a novel iteration-free blind phase noise estimation scheme for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. In the new algorithm, the cost function is selected as the sim...We propose a novel iteration-free blind phase noise estimation scheme for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. In the new algorithm, the cost function is selected as the similar expression with real and imaginary parts as that in the modified constant modulus algorithm, and the new cost function is derived under some assumptions, where it is infinitely approximated by the sine and cosine functions. By means of the analytical formula of the cost function, the initial coarse common phase error can be obtained with only some samples, where the algorithm avoids computational complexity of conventional blind phase noise compensation scheme. In CO-OFDM systems with high-order modulation format (32 quadrature amplitude modulation) and narrow linewidth lasers, it is proved by the simulation results that the nhase noise can be effectively compensated with the proposed blind estimation method.展开更多
Experiment was conducted to study Gaussian pulse transmission over ultra-high PMD fiber. Gaussian pulse is broken into a series of deformed pulses when it transmits over ultra-high PMD fiber. It is indicated that the ...Experiment was conducted to study Gaussian pulse transmission over ultra-high PMD fiber. Gaussian pulse is broken into a series of deformed pulses when it transmits over ultra-high PMD fiber. It is indicated that the walk-off deformed pulses were caused by ultra-high PMD. Transmitted experiment has been done using fiber with PMD coefficient 237.95ps/km1/2. The result of the experiment is consistent with the simulated one.展开更多
基金supported in part by the National Key R&D Program of China under Grant No.2019YFB2205302。
文摘Low-cost,flexible and intelligent optical performance monitoring and management is a key enabling technology for network quality guarantee,especially in the era of explosive growth of communication capacity and network scale.However,to the best of our knowledge,it is extremely challenging to implement real-time performance monitoring and operations,administration and maintenance(OAM) in a highly complex dynamic network.In this paper,we propose an innovative optical identification(OID) scheme that can realize both performance monitoring and some advanced OAM sub-functions.The basic concepts,applications,challenges and evolution directions of this OID tool are also discussed.
文摘<div style="text-align:justify;"> In order to meet the needs of the rapid development of optical fiber communication technology, combined with the thinking of the Internet of Things, a new idea of designing an optical fiber test equipment using Raspberry Pi is proposed. At the same time, the design of a multi-parameter measuring device for optical fiber signals based on Flask was completed. </div>
基金supported by the National Science Foundation of China(Grant Nos.60977049)the National 863 High Tech Research and Development Program of china(Grant No.2009AA01Z220,2009AA01Z222)Program for Hunan Provincial Science and technology
文摘In this paper, we describe a novel technique based on the flipped-exponential (FE) Nyquist pulse method for reducing peak-to-average power ratio (PAPR) in an optical direct-detection orthogonal frequency-division multiplexing (DD-QFDM) system, The technique involves proper selection of the FE Nyquist pulses for shaping the different subcarriers of the OFDM. We apply this technique to a DD-OFDM transmission system to significantly reduce PAPR. We also investigate the sensitivity of a received OFDM signal with strong nonlinearity in a standard single-mode fiber (SMF).
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60972017,60978007,and 61177067)
文摘The operational parameters including the polarization controlling and the pump power in a nonlinear polarization rotation-based passively mode-locked fiber laser are studied in this paper.The carrier rate equations of the activated erbium-doped fiber are first employed together with the nonlinear Shro¨dinger equations to reveal the relation between the operational parameters and the output state of the passively mode-locked fiber laser.The numerical and experimental results demonstrate that the output state of the mode-locked laser varies with the polarization controlling and the pump power.The periodicity of the polarization controlling is observed.With given pump power,there exists a set of polarization controlling under which the ultra-short pulse can be generated.With given polarization controlling,the mode-locked state can be maintained generally except for some particular values of pump power.Three shapes of the output optical spectra from the fiber cavity can be identified when the pump power changes.The results in this paper provide a comprehensive insight into the operation of the nonlinear polarization rotation-based passively mode-locked fiber laser.
文摘In this paper, the transceiver performance of optical 64QAM-OFDM signals with different sub-car- riers is studied. Firstly, we build a 40Gbit/s optical coherent 64QAM-OFDM transmission system. 64QAM-OFDM optical signals with 16, 32, 64, 64, 128, 256 and 512 sub-carriers are transmitted over 100 km single mode fiber (SMF). Then, the optical spectrum diagrams before and after transmission, the bit error rate (BER) and constellation diagrams of received signals were compared. The simulation results show that, with the number of sub-carriers increasing, the value of PAPR will gradually increase and the quality of the received optical signals will deteriorate. Moreover, with the number of sub-carriers increasing, the computational complexity will increase when digital signal processing (DSP) is used. Therefore, we should choose the optimal number of sub-carriers, and the PAPR influence and BER are also considered for achieving effective transmission.
文摘A CWDM is proposed for fiber optic communication networks. The OADM is designed based on SOI structure. The scheme for CWDM optical signal protection is presented.
基金supported by the National Key Research and Development Program of China(under Grant 2020YFB1600203).
文摘With the continuous development of automotive intelligent networking and autonomous driving technologies,the number of in-vehicle electronic systems and applications is increasing rapidly.This change increases the amount of data to be transmitted in the vehicle and puts forward further requirements of higher speed and safety for in-vehicle communication.Traditional vehicle bus technologies are no longer sufficient to meet today’s high-speed transmission requirements,in which copper cables are used extensively,resulting in serious electromagnetic interference(EMI).Vehicle optical fiber communication technology,besides greatly improving the data transmission rate,has the advantages of anti-EMI,reducing cable space and vehicle mass.This paper first presents the motivation of applying vehicle optical fiber communication technology and reviews the development history of vehicle optical fiber communication technology.Then,the paper researches the devel-opment trend of automotive electrical and electronic architecture(EEA),from distributed EEA to domain centralized EEA and zone-oriented EEA.Based on the discussion of the development trend of automotive EEA,an EEA based on vehicle optical fiber communication technology is proposed.Finally,the key points and future directions of vehicle optical fiber communication technology research are highlighted,including vehicle multi-mode optical fiber technology,vehicle optical fiber network protocol,and topology.
基金supported by the National Key R&D Program of China(No.2018YFB1800905)the National Natural Science Foundation of China(Nos.61935005,61720106015,61835002,and 62127802)。
文摘We experimentally transmit eight wavelength-division-multiplexing(WDM)channels,16 quadratic-amplitude-modulation(QAM)signals at 32-GBaud,over 1000 km few mode fiber(FMF).In this experiment,we use WDM,mode division multiplexing,and polarization multiplexing for signal transmission.Through the multiple-input-multiple-output(MIMO)equalization algorithms,we achieve the total line transmission rate of 4.096 Tbit/s.The results prove that the bit error rates(BERs)for the16QAM signals after 1000 km FMF transmission are below the soft-decision forward-error-correction(SD-FEC)threshold of2.4×10^(-2),and the net rate reaches 3.413 Tbit/s.Our proposed system provides a reference for the future development of high-capacity communication.
基金supported by the Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong University(Grant No.21TQ1400213)the National Natural Science Foundation of China(Grant No.62175145)
文摘Optical networks are evolving toward ultrawide bandwidth and autonomous operation.In this scenario,it is crucial to accurately model and control optical power evolutions(OPEs)through optical amplifiers(OAs),as they directly affect the signal-to-noise ratio and fiber nonlinearities.However,a fundamental contradiction arises between the complex physical phenomena in optical transmission and the required precision in network control.Traditional theoretical methods underperform due to ideal assumptions,while data-driven approaches entail exorbitant costs associated with acquiring massive amounts of data to achieve the desired level of accuracy.In this work,we propose a Bayesian inference framework(BIF)to construct the digital twin of OAs and control OPE in a data-efficient manner.Only the informative data are collected to balance the exploration and exploitation of the data space,thus enabling efficient autonomous-driving optical networks(ADONs).Simulations and experiments demonstrate that the BIF can reduce the data size for modeling erbium-doped fiber amplifiers by 80%and Raman amplifiers by 60%.Within 30 iterations,the optimal controlling performance can be achieved to realize target signal/gain profiles in links with different types of OAs.The results show that the BIF paves the way to accurately model and control OPE for future ADONs.
文摘An optical PPM CDMA communication system with an optical hard limiter in front of the correlator of a receiver is proposed in order to reduce multi user interference. The performance of the system is evaluated when the effects of both multi user interference and photo detector shot noise are considered. An upper bound on the bit error rate is derived. The comparison of the performance of the above receiver with that of the optical PPM CDMA system without an optical hard limiter is made. Simulation results show that the performance of the system with an optical hard limiter is superior to that of the conventional one.
基金National Science Foundation of China(NSFC)(61871082 and 62111530150)Fundamental Research Funds for the Central Universities(ZYGX2020ZB043 and ZYGX2019J008).
文摘As the emergence of various highbandwidth services and the requirements to support 5G/Wi-Fi 6 wireless networks,the next generation fixed networks,i.e.F5G,are expected to be realized in the 5G era.F5G is endowed with new characteristics,including ultra-high bandwidth,all-optical connections and optimal service experience.With the prospect of optical-to-everywhere,optical technologies are used for mobile front-haul,mid-haul,and back-haul.Optical access networks would play an important role in F5G to support radio access network and fixed access network.Low-latency PON is a key for cost effective-haul traffic aggregation.In terms of signal transmission,intensity modulation directdetection(IM-DD)is a promising scheme due to its simple architecture.The fundamental challenge associated with direct-detection is the disappearance of the transmitted signal’s phase.In access network,the flexibility and low latency are the two key factors affecting service experience.In this article,we review the evolution of PONs and the challenges of current PONs in detail.We analyze key enabling digital signal processing(DSP)techniques,including detection linearization for direct-detection and simplified coherent detection,adaptive equalizers,digital filer enabled flexible access network and low-latency inter-ONU communications.Finally,we discuss the developing trends of future optical access networks.
文摘This paper begins with Nyquist wavelengthdivision multiplexing (WDM) and then introduces fasterthanNyquist. In fasterthanNyquist a certain amount of intersymbol interference (ISI) is accepted, which violates the fundamental principle of Nyquist WDM. This results in muchrelaxed transceiver bandwidth and simpler spectral design. However, in fasterthanNyquist, implementation complexity is shifted from the transmitter side to the receiver side. Therefore, successful application of fasterthanNyquist depends on innovation in the receiver structure. In this paper, we discuss the guidelines for implementing suboptimum, lowcomplexity receivers based on fasterthanNyquist. We suggest that duobinary shaping is a good technique for trading off achievable spectral efficiency, detection performance, and implementation complexity and might be preferable to Nyquist WDM. Experiments are conducted to verify robustness of the proposed technique.
文摘An equivalent noise model of optical receiver amplifiers as shown in Fig.1 has been given in many fiber optical communication literatures. It is proved in this paper that this equivalent noise model is neither equivalent to the original one nor measurable. The main reason is that the position of the input impedance in this noise model is not the same with its in the typical noise model,but the same S vn , S in with the typical noise model are used. So the equivalent noise model above is wrong and is not fit to be taken into application.
基金supported by NSFC Projects(Grant No.:61901053,61831003,62021005)the Fundamental Research Funds for the Central Universities(2021RC12).
文摘In quantum noise stream cipher(QNSC)systems,it is difficult to compensate fiber nonlinearity by digital signal processing(DSP)due to interactions between chromatic dispersion(CD),amplified spontaneous emission(ASE)noise from erbiumdoped fiber amplifier(EDFA)and Kerr nonlinearity.Nonlinearity equalizer(NLE)based on machine learning(ML)algorithms have been extensively studied.However,most NLE based on supervised ML algorithms have high training overhead and computation complexity.In addition,the performance of these algorithms have a lot of randomness.This paper proposes two clustering algorithms based on Fuzzylogic C-Means Clustering(FLC)to compensate the fiber nonlinearity in quadrature amplitude modulation(QAM)-based QNSC system,including FLC based on subtractive clustering(SC)and annealing evolution(AE)algorithm.The performance of FLC-SC and FLC-AE are evaluated through simulation and experiment.The proposed algorithms can promptly obtain suitable initial centroids and choose optimal initial centroids of the clusters to achieve the global optimal initial centroids especially for high order modulation scheme.In the simulation,different parameter configurations are considered,including fiber length,optical signal-to-noise ratio(OSNR),clipping ratio and resolution of digital to analog converter(DAC).Further-more,we measure the Q-factor of transmission signal with different launched powers,DAC resolution and laser linewidth in the optical back-to-back(BTB)experiment with 80-km single mode fiber.Both simulation and experimental results show that the proposed techniques can greatly mitigate the signal impairments.
文摘In this paper the expression of the output pulse Stokes vector is derived based on the Jones matrix model proposed by A.Orlandini et al. The basic properties of degree of polarization (DOP) for output pulse are investigated.
基金supported by the National Key R&D Program of China(No.2019YFB1803504)the National Natural Science Foundation of China(Nos.61821001,61901045,and 61625104)the Fund of State Key Laboratory of Information Photonics and Optical Communication BUPT(No.IPOC2021ZT18)。
文摘In this paper,we propose and experimentally demonstrate a joint shaping technique to improve the performance of a lowresolution transmission system for the first time,to the best of our knowledge.The joint shaping technique combines probabilistic shaping(PS)and error feedback noise shaping(EFNS).In the 40-Gbaud intensity-modulation direct-detection(IM/DD)experimental transmission system,a bit-error-rate(BER)of 3.8×10^(-3)can be achieved easily with the joint shaping at the physical number of bits(PNOB)of 3.In the 30-Gbaud dual polarization(DP)coherent experimental transmission system,a BER below 1×10^(-3)is easily obtained with a 3-bit quantizer by using joint shaping.The optimization of the shaping degree is also analyzed.
文摘F, K, 1) Optical orthogonal codes (OOC) are the best address codes applied to optical code division multiple access (OCDMA) communication systems, but the construction of the codes is very complex. In this paper, a method of construction of the OOC from block design is discussed and a method of computer aid design is presented, by which we can construct desired (F, K, 1) OOC easily.
基金supported in part by the China Postdoctoral Science Foundation(No.2013M540361)the National Natural Science Foundation of China(Nos.60907032 and 61275124)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LY13F010011)the Zhejiang Youth Science Fund(No.LQ13F050005)
文摘We propose a novel iteration-free blind phase noise estimation scheme for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. In the new algorithm, the cost function is selected as the similar expression with real and imaginary parts as that in the modified constant modulus algorithm, and the new cost function is derived under some assumptions, where it is infinitely approximated by the sine and cosine functions. By means of the analytical formula of the cost function, the initial coarse common phase error can be obtained with only some samples, where the algorithm avoids computational complexity of conventional blind phase noise compensation scheme. In CO-OFDM systems with high-order modulation format (32 quadrature amplitude modulation) and narrow linewidth lasers, it is proved by the simulation results that the nhase noise can be effectively compensated with the proposed blind estimation method.
基金supported by the National Natural Science Foundation of China(Grant No.69903001)863 Project of China(2001AA122042)Pandeng Foundation of Northern Jiaotong University
文摘Experiment was conducted to study Gaussian pulse transmission over ultra-high PMD fiber. Gaussian pulse is broken into a series of deformed pulses when it transmits over ultra-high PMD fiber. It is indicated that the walk-off deformed pulses were caused by ultra-high PMD. Transmitted experiment has been done using fiber with PMD coefficient 237.95ps/km1/2. The result of the experiment is consistent with the simulated one.