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
Spatial modedivision multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dualmode, dualpolarization transmission method based on modeselec...Spatial modedivision multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dualmode, dualpolarization transmission method based on modeselective excitation and detection over a twomode fiber. In particular, we present 107 Gbit/s coherent optical OFDM （COOFDM） transmission over a 4.5 km twomode fiber using LP and LP. modes in which mode separation is performed optically.展开更多
We propose a nonbinary byte-interleaved coded-modulation scheme with inner and outer turbo-like iterative decoder.The net coding gain is 0.6 d B higher than the state-of-the-art binary single parity check(SPC)low-dens...We propose a nonbinary byte-interleaved coded-modulation scheme with inner and outer turbo-like iterative decoder.The net coding gain is 0.6 d B higher than the state-of-the-art binary single parity check(SPC)low-density parity-check(LDPC)based turbo-product counterpart,with adjustable iterations and lower error-floor.We provide the details of Bahl-CockeJelinek-Raviv(BCJR)based inner code decoder and optimum signal constellation design(OSCD)method in this paper.The single-mode fiber(SMF)channel simulation is also discussed.展开更多
A novel chaotic optical time-domain reflectometry(OTDR)-based approach was proposed for monitoring long-haul fiber communication systems with multiple fiber segments. The self-phase modulation and group velocity dispe...A novel chaotic optical time-domain reflectometry(OTDR)-based approach was proposed for monitoring long-haul fiber communication systems with multiple fiber segments. The self-phase modulation and group velocity dispersion effects of the optical cable was considered in demonstrating the proof-of-concept experiment and simulation. In experiments, the correlation peaks are clearly obtained from the correlation trace between the reference and reflected(or scattered) light signals propagating in three optical-fiber segments. The technique affords a high spatial resolution of 2 m, and further long-haul fiber simulations indicate that the sensing distance can be more than 3300 km. Thus, the new proposed technique can be effectively applied for health monitoring of long-haul fiber communication systems.展开更多
The factors which cause additional losses of guidance optical fiber in wound state were analyzed.A mathematical model used to analyze the macro-bend losses in the cross region producing in the precision winding proces...The factors which cause additional losses of guidance optical fiber in wound state were analyzed.A mathematical model used to analyze the macro-bend losses in the cross region producing in the precision winding process was established.For an actual guidance optical fiber,the measured data of the fiber's additional losses under low temperature and the loss curves with radius were given in the paper.The simulation results were compared with the test data.It shows that the additional losses of optical fiber caused by bending and low temperature can meet the actual requirements of the fiber optical guidance system.The established model can be used to predict the change trend of fiber losses in the winding process with a certain tensile force.展开更多
This paper introduces a new-developed mine fire-resistant optical fiber cable (OFC)KL5004,its structural characteristics, main feature, the theory about fire resistance and its application in high output and efficienc...This paper introduces a new-developed mine fire-resistant optical fiber cable (OFC)KL5004,its structural characteristics, main feature, the theory about fire resistance and its application in high output and efficiency mine.展开更多
The macropore silica colloidal crystal templates were assembled orderly in a capillary glass tube by an applied electric field method to control silica deposition. In order to achieve the photonic band gap （PBG） of ...The macropore silica colloidal crystal templates were assembled orderly in a capillary glass tube by an applied electric field method to control silica deposition. In order to achieve the photonic band gap （PBG） of colloidal crystal in optical communication waveband, the diameter of silica microspheres is selected by Bragg diffraction formula. An experiment was designed to test the bandgap of the silica crystal templates. This paper discusses the formation process and the close-packed fashion of the silica colloidal crystal templates was discussed. The surface morphology of the templates was also analyzed. The results showed that the close-packed fashion of silica array templates was face-centered cubic （FCC） structure： The agreement is very good between the experimental data and the theoretical calculation.展开更多
100 G Ethernet is considered to become the next generation Ethernet standard for IP networks.Typical 100 Gb/s transmission systems and their performance are presented.Comparision and analysis for 100 Gb/s transmission...100 G Ethernet is considered to become the next generation Ethernet standard for IP networks.Typical 100 Gb/s transmission systems and their performance are presented.Comparision and analysis for 100 Gb/s transmission systems have been discussed.It is demonstrated that optical OFDM can be used in future 100 Gb/s/ch and long-haul system.展开更多
Fiber nonlinearity is one of the most important limiters of capacity in coherent optical communications. In this paper, we review two nonlinear compensation methods： digital backward propagation （BP） and nonlinear ...Fiber nonlinearity is one of the most important limiters of capacity in coherent optical communications. In this paper, we review two nonlinear compensation methods： digital backward propagation （BP） and nonlinear electrical equalizer （NLEE） based on the timedomain Volterra series. These compensation algorithms are implemented in a singlechannel 50 Gb/s coherent optical singlecarrier frequency division multiplexed （CO-SCFDM） system transmitting over 10 × 80 km of standard singlemode fiber （SSMF）.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
Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fibe...Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fiber coupling. In this paper, we verified a new adaptive-optic device named adaptive fiber coupler （AFC） which could compensate angular jitters and improve the SMF coupling efficiency in some degree. Experiments of SMF coupling under the angular jitter situation using AFC have been achieved. Stochastic parallel gradient descent （SPGD） algorithm is employed as the control strategy, of which the iteration rate is 625 Hz. In closed loop, the coupling efficiency keeps above 65% when angular errors are below 80/3tad. The compensation bandwidth is 35 Hz at sine-jitter of 15 ~rad amplitude with average coupling efficiency of above 60%. Also, experiments with simulated turbulence have been studied. The average coupling efficiency increases from 31.97% in open loop to 61.33% in closed loop, and mean square error （MSE） of coupling efficiency drops from 7.43% to 1.75%.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
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
Polarization-division multiplexing(PDM)with modulation in the nonlinear frequency domain consisting of the discrete and/or continuous spectrum has been recently regarded as a useful method to be utilized in optical fi...Polarization-division multiplexing(PDM)with modulation in the nonlinear frequency domain consisting of the discrete and/or continuous spectrum has been recently regarded as a useful method to be utilized in optical fiber communication system.It can compensate the optical fiber nonlinearity based on the nonlinear Fourier transform(NFT).In this paper,we combine PDM with the method of nonlinear frequency division multiplexing(NFDM)and demonstrate the achievable transmission rate by increasing the number of multiplexing nonlinear channels.For the selected subcarriers(i.e.32,64,and 128),the transmission rates are 64 Gbit/s,76.8 Gbit/s,and 109.7 Gbit/s respectively by applying 64-quadrature amplitude modulation(64-QAM)on the nonlinear continuous spectrum.For the transmission distance shorter than 1200 km,the transmission rate of 128-NFDM PDM system can even reach up to 153.6 Gbit/s.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
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
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Spatial modedivision multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dualmode, dualpolarization transmission method based on modeselective excitation and detection over a twomode fiber. In particular, we present 107 Gbit/s coherent optical OFDM （COOFDM） transmission over a 4.5 km twomode fiber using LP and LP. modes in which mode separation is performed optically.
文摘We propose a nonbinary byte-interleaved coded-modulation scheme with inner and outer turbo-like iterative decoder.The net coding gain is 0.6 d B higher than the state-of-the-art binary single parity check(SPC)low-density parity-check(LDPC)based turbo-product counterpart,with adjustable iterations and lower error-floor.We provide the details of Bahl-CockeJelinek-Raviv(BCJR)based inner code decoder and optimum signal constellation design(OSCD)method in this paper.The single-mode fiber(SMF)channel simulation is also discussed.
基金the Project Funding National Natural Science Foundation of China (NSFC) (61527819)University Natural Science Research Project of Jiangsu Province (19KJB510005)High-Level Training Fund project of Nanjing Xiaozhuang University (2019NXY18)
文摘A novel chaotic optical time-domain reflectometry(OTDR)-based approach was proposed for monitoring long-haul fiber communication systems with multiple fiber segments. The self-phase modulation and group velocity dispersion effects of the optical cable was considered in demonstrating the proof-of-concept experiment and simulation. In experiments, the correlation peaks are clearly obtained from the correlation trace between the reference and reflected(or scattered) light signals propagating in three optical-fiber segments. The technique affords a high spatial resolution of 2 m, and further long-haul fiber simulations indicate that the sensing distance can be more than 3300 km. Thus, the new proposed technique can be effectively applied for health monitoring of long-haul fiber communication systems.
文摘The factors which cause additional losses of guidance optical fiber in wound state were analyzed.A mathematical model used to analyze the macro-bend losses in the cross region producing in the precision winding process was established.For an actual guidance optical fiber,the measured data of the fiber's additional losses under low temperature and the loss curves with radius were given in the paper.The simulation results were compared with the test data.It shows that the additional losses of optical fiber caused by bending and low temperature can meet the actual requirements of the fiber optical guidance system.The established model can be used to predict the change trend of fiber losses in the winding process with a certain tensile force.
文摘This paper introduces a new-developed mine fire-resistant optical fiber cable (OFC)KL5004,its structural characteristics, main feature, the theory about fire resistance and its application in high output and efficiency mine.
基金Project supported by Science and Technology Foundation of Jiangsu Province (Grant No BE2008138)
文摘The macropore silica colloidal crystal templates were assembled orderly in a capillary glass tube by an applied electric field method to control silica deposition. In order to achieve the photonic band gap （PBG） of colloidal crystal in optical communication waveband, the diameter of silica microspheres is selected by Bragg diffraction formula. An experiment was designed to test the bandgap of the silica crystal templates. This paper discusses the formation process and the close-packed fashion of the silica colloidal crystal templates was discussed. The surface morphology of the templates was also analyzed. The results showed that the close-packed fashion of silica array templates was face-centered cubic （FCC） structure： The agreement is very good between the experimental data and the theoretical calculation.
基金supported by NSFC(no60872035)Youthful foundation of UESTC JX0707Key Youthful foundation of UESTC JX0801
文摘100 G Ethernet is considered to become the next generation Ethernet standard for IP networks.Typical 100 Gb/s transmission systems and their performance are presented.Comparision and analysis for 100 Gb/s transmission systems have been discussed.It is demonstrated that optical OFDM can be used in future 100 Gb/s/ch and long-haul system.
基金supported by National Natural Science Foundation of China (No. 61077053, 60932004, and60877045)National Basic Research Program of China(No. 2010CB328201)
文摘Fiber nonlinearity is one of the most important limiters of capacity in coherent optical communications. In this paper, we review two nonlinear compensation methods： digital backward propagation （BP） and nonlinear electrical equalizer （NLEE） based on the timedomain Volterra series. These compensation algorithms are implemented in a singlechannel 50 Gb/s coherent optical singlecarrier frequency division multiplexed （CO-SCFDM） system transmitting over 10 × 80 km of standard singlemode fiber （SSMF）.
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 No. 61205069）.
文摘Coupling plane wave into a single-mode fiber （SMF） with high and steady coupling efficiency is crucial for fiber- based free-space laser systems, where random angular jitters are the main influencing factors of fiber coupling. In this paper, we verified a new adaptive-optic device named adaptive fiber coupler （AFC） which could compensate angular jitters and improve the SMF coupling efficiency in some degree. Experiments of SMF coupling under the angular jitter situation using AFC have been achieved. Stochastic parallel gradient descent （SPGD） algorithm is employed as the control strategy, of which the iteration rate is 625 Hz. In closed loop, the coupling efficiency keeps above 65% when angular errors are below 80/3tad. The compensation bandwidth is 35 Hz at sine-jitter of 15 ~rad amplitude with average coupling efficiency of above 60%. Also, experiments with simulated turbulence have been studied. The average coupling efficiency increases from 31.97% in open loop to 61.33% in closed loop, and mean square error （MSE） of coupling efficiency drops from 7.43% to 1.75%.
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.
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Polarization-division multiplexing(PDM)with modulation in the nonlinear frequency domain consisting of the discrete and/or continuous spectrum has been recently regarded as a useful method to be utilized in optical fiber communication system.It can compensate the optical fiber nonlinearity based on the nonlinear Fourier transform(NFT).In this paper,we combine PDM with the method of nonlinear frequency division multiplexing(NFDM)and demonstrate the achievable transmission rate by increasing the number of multiplexing nonlinear channels.For the selected subcarriers(i.e.32,64,and 128),the transmission rates are 64 Gbit/s,76.8 Gbit/s,and 109.7 Gbit/s respectively by applying 64-quadrature amplitude modulation(64-QAM)on the nonlinear continuous spectrum.For the transmission distance shorter than 1200 km,the transmission rate of 128-NFDM PDM system can even reach up to 153.6 Gbit/s.
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.
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.
