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
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
The influence of the nonlinear propagation effect on three 400 Gb/s/ch (400G) optical fiber communication systems with typical modulation formats, dual-carrier 16-quadrature amplitude modulation (16QAM), single-ca...The influence of the nonlinear propagation effect on three 400 Gb/s/ch (400G) optical fiber communication systems with typical modulation formats, dual-carrier 16-quadrature amplitude modulation (16QAM), single-carrier 16QAM (single-16QAM), and four-carrier quadrature phase-shift keying, are investigated. The received optical signal-to-noise ratio (OSNR), affected by the nonlinear interference noise together with the amplified spontaneous emission noise, are compared with three 400G systems and a standard 100 Gb/s/ch system by numerical simulations. Both single channel and multichannel cases are considered. Single-16QAM is found to have the best OSNR among those modulation formats.展开更多
The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitiv...The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitive to the signal degradation caused by chromatic dispersion and nonlinearity in optical fibers. The influence of timing jitter and amplitude fluctuation of the sampling pulses is also investigated. It is found that stringent requirements are imposed on the quality of the sampling pulse and the tolerance of 1-dB Q penalty is measured. Considering the practically available optical sampling pulse sources, the results indicate that the amplitude fluctuation of the sampling pulses has the dominant impacts on the software-synchronized method.展开更多
We propose a method of modulation format identification based on compressed sensing using a high-order cyclic cumulant combined with a binary tree classifier.Through computing the fourth-order cyclic cumulant of the p...We propose a method of modulation format identification based on compressed sensing using a high-order cyclic cumulant combined with a binary tree classifier.Through computing the fourth-order cyclic cumulant of the pretreated band signal,which is obtained by compressed sensing with the sampling rate much less than the Nyquist sampling value,the feature vector for classification is extracted.Simulations are carried out in the optical coherent fiber communication system with different modulation formats of multiple phase-shift keying and multiple quadrature amplitude modulation.The results indicate that this method can identify these modulation formats correctly and efficiently.Meanwhile,the proposed method is insensitive to laser phase noise and signal noise.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 optical fiber gas sensor mainly consists of two parts: optical part and detection circuit. In the debugging for the detection circuit, the optical part usually serves as a signal source. However, in the debugging ...An optical fiber gas sensor mainly consists of two parts: optical part and detection circuit. In the debugging for the detection circuit, the optical part usually serves as a signal source. However, in the debugging condition, the optical part can be easily influenced by many factors, such as the fluctuation of ambient temperature or driving current resulting in instability of the wavelength and intensity for the laser; for dual-beam sensor, the different bends and stresses of^the optical fiber will lead to the fluctuation of the intensity and phase; the intensity noise from the collimator, coupler, and other optical devices in the system will also result in the impurity of the optical part based signal source. In order to dramatically improve the debugging efficiency of the detection circuit and shorten the period of research and development, this paper describes an analog signal source, consisting of a single chip microcomputer (SCM), an amplifier circuit, and a voltage-to-current conversion circuit. It can be used to realize the rapid debugging detection circuit of the optical fiber gas sensor instead of optical part based signal source. This analog signal source performs well with many other advantages, such as the simple operation, small size, and light weight.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
An improved zero-interpolation method with signal clipping to improve fiber nonlinearity tolerance in the long-haul coherent optical orthogonal frequency division multiplexing system (CO-OFDM) is presented. The new ...An improved zero-interpolation method with signal clipping to improve fiber nonlinearity tolerance in the long-haul coherent optical orthogonal frequency division multiplexing system (CO-OFDM) is presented. The new technique is implemented by interpolating zero subcarriers and selecting the odd subcarriers to carry data and clipping conventional CO-OFDM signal at zero. With such a scheme,the effect of fiber nonlinearity can be miti-gated,and the wanted signal carried on odd subcarriers is or-thogonal to clipping noise,which falls on even frequencies. Simu-lation shows that the system Q value is improved by more than 2 dB at the length of 960 km展开更多
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.
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 Key Scientific Instrument and Equipment Development Project of China under Grant No.2014YQ510403
文摘The influence of the nonlinear propagation effect on three 400 Gb/s/ch (400G) optical fiber communication systems with typical modulation formats, dual-carrier 16-quadrature amplitude modulation (16QAM), single-carrier 16QAM (single-16QAM), and four-carrier quadrature phase-shift keying, are investigated. The received optical signal-to-noise ratio (OSNR), affected by the nonlinear interference noise together with the amplified spontaneous emission noise, are compared with three 400G systems and a standard 100 Gb/s/ch system by numerical simulations. Both single channel and multichannel cases are considered. Single-16QAM is found to have the best OSNR among those modulation formats.
基金supported by the National Natural Sci-ence Foundation of China (No. 60777024)the Open Fund of Key Laboratory of Optical Communication and Lightwave Technologies,Beijing University of Posts and Telecommunications, Ministry of Education, China
文摘The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitive to the signal degradation caused by chromatic dispersion and nonlinearity in optical fibers. The influence of timing jitter and amplitude fluctuation of the sampling pulses is also investigated. It is found that stringent requirements are imposed on the quality of the sampling pulse and the tolerance of 1-dB Q penalty is measured. Considering the practically available optical sampling pulse sources, the results indicate that the amplitude fluctuation of the sampling pulses has the dominant impacts on the software-synchronized method.
基金supported by the National Natural Science Foundation of China(Nos.61571057 and 61501213)the Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),P.R.China(No.IPOC2016ZT12)the Open Fund of the Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications(Jinan University)
文摘We propose a method of modulation format identification based on compressed sensing using a high-order cyclic cumulant combined with a binary tree classifier.Through computing the fourth-order cyclic cumulant of the pretreated band signal,which is obtained by compressed sensing with the sampling rate much less than the Nyquist sampling value,the feature vector for classification is extracted.Simulations are carried out in the optical coherent fiber communication system with different modulation formats of multiple phase-shift keying and multiple quadrature amplitude modulation.The results indicate that this method can identify these modulation formats correctly and efficiently.Meanwhile,the proposed method is insensitive to laser phase noise and signal noise.
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This work was supported by the Natural Science Foundation of China (60977058) and the Fundamental Research Funds of Shandong University (2014YQ011).
文摘An optical fiber gas sensor mainly consists of two parts: optical part and detection circuit. In the debugging for the detection circuit, the optical part usually serves as a signal source. However, in the debugging condition, the optical part can be easily influenced by many factors, such as the fluctuation of ambient temperature or driving current resulting in instability of the wavelength and intensity for the laser; for dual-beam sensor, the different bends and stresses of^the optical fiber will lead to the fluctuation of the intensity and phase; the intensity noise from the collimator, coupler, and other optical devices in the system will also result in the impurity of the optical part based signal source. In order to dramatically improve the debugging efficiency of the detection circuit and shorten the period of research and development, this paper describes an analog signal source, consisting of a single chip microcomputer (SCM), an amplifier circuit, and a voltage-to-current conversion circuit. It can be used to realize the rapid debugging detection circuit of the optical fiber gas sensor instead of optical part based signal source. This analog signal source performs well with many other advantages, such as the simple operation, small size, and light weight.
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.
基金Supported by the National Natural Science Foundation of China (60871075)
文摘An improved zero-interpolation method with signal clipping to improve fiber nonlinearity tolerance in the long-haul coherent optical orthogonal frequency division multiplexing system (CO-OFDM) is presented. The new technique is implemented by interpolating zero subcarriers and selecting the odd subcarriers to carry data and clipping conventional CO-OFDM signal at zero. With such a scheme,the effect of fiber nonlinearity can be miti-gated,and the wanted signal carried on odd subcarriers is or-thogonal to clipping noise,which falls on even frequencies. Simu-lation shows that the system Q value is improved by more than 2 dB at the length of 960 km