共查询到20条相似文献,搜索用时 46 毫秒
1.
F. M. Abbou C. C. Hiew H. T. Chuah D. S. Ong A. Abid 《Journal of Russian Laser Research》2008,29(1):57-70
A performance analysis is carried out to evaluate the effect of cross-phase modulation (XPM) on a dispersion-managed 20 Gb/s
optical wavelength-division multiplexing (WDM) transmission system using either the on-off keying (OOK) or the different-phase-shifting
keying (DPSK) modulation, in the presence of the group-velocity dispersion (GVD), self-phase modulation (SPM), and amplified
spontaneous emission (ASE). It is found that to achieve a bit error rate (BER) of 10−9 at a distance of 160 km, a 1.0 dB XPM power penalty is incurred for input channel power of 3 dBm in the OOK transmission
and 7 dBm in the DPSK transmission. The power penalty increases with input channel powers and is inversely proportional and
exhibits oscillations with respect to the channel separation. The oscillation is evenly spaced for the DPSK but not for the
OOK and suggests the presence of optimum separation values. The XPM penalty decreases when a high dispersion fiber is used
and increases linearly with increasing dispersion slope. Small residual dispersion can reduce the penalty of nonlinear effects. 相似文献
2.
3.
The nonlinear effects that limit the performance of the multi-frequency probe(MFP)based coherent optical time domain reflectometry(C-OTDR)are investigated.Based on theoretical analysis and experimental results,compared with conventional C-OTDR,when the probe pulse has power gradient within the pulse width,self-phase modulation(SPM)and cross-phase modulation(XPM)are strengthened in the new C-OTDR scheme.The generation of four-wave mixing(FWM)is dependent on SPM and XPM,and with modulation frequency of phase modulator higher than 40 MHz,the stimulated Brillouin scattering(SBS) threshold can be enhanced by more than 5 dB,which benefits the maximum dynamic range of the MFP C-OTDR. 相似文献
4.
光纤非线性效应对10 Gb/s波分复用色散补偿系统的限制 总被引:2,自引:2,他引:0
对信道间距为100GHz的8倍10Gb/s波分复用色散补偿系统进行了计算机仿真,分析了光纤的色散和自相位调制(SPM)、互相位调制(XPM)、四波混频(FWM)等非线性效应在具有级联光放大器系统中的作用。四种色散补偿方案是:SMF(常规单模光纤)+DCF1(色散斜率为正的色散补偿光纤)、SMF+DCF2(色散斜率为负的色散补偿光纤)、TW1(色散为正的非零色散光纤)+TW2(色散为负的非零色散光纤 相似文献
5.
The modulation instability of continuous waves for a system of four coupled nonlinear Schrödinger equations, two of which are in the unstable regime, is studied. In earlier studies, plane or continuous waves for a system of two coupled, nonlinear Schrödinger equations is shown to exhibit modulation instability (MI), even if both modes are in the normal dispersion regime, provided that the coefficient of cross phase modulation (XPM) is larger than that of self phase modulation (SPM). Requirements for MI in this system of four coupled, nonlinear Schrödinger equations can be relaxed. MI can occur even if the magnitude of XPM is less than that of SPM, and the magnitude of instability is generally larger than that of each mode alone. The implications for parametric process and wavelength exchange in optical physics with two pump waves are discussed. 相似文献
6.
CrostalkinWDMSCMSystemsduetoSRSZHAOLiangXUDayongWUDemingYUANHongXUAnshi(DepartmentofElectronics,BeijingUniversityNationalKeyL... 相似文献
7.
光正交频分复用系统中的光纤非线性效应制约着系统进一步的扩容. 针对此问题, 提出一种数字相干叠加的方法, 用于提高相干光正交频分复用系统对光纤非线性的容忍性. 仿真中, 5通道的波分复用下偏振复用相干光正交频分复用系统的每个通道传输四进制正交振幅调制映射的71.53 Gbit/s信号在光纤中传输400 km. 首先, 通道间隔为25 GHz, 与传统相干光正交频分复用系统相比, 色散补偿前后, 使用数字相干叠加的相干光正交频分复用系统的信噪比分别提升了6.02 dB和9.05 dB, 最佳入纤光功率均增大了2 dB; 其次, 通道间隔为50 GHz, 色散补偿前后, 信噪比分别提升了4.9 dB和8.75 dB. 通过理论推导及仿真, 验证了所提方法能有效消除相干光正交频分复用系统的一阶非线性失真, 进而提高系统对光纤非线性的容忍性. 相似文献
8.
Cross-phase modulation-induced penalties in multichannel DWDM optical transport networks 总被引:1,自引:0,他引:1
In dense wavelength division multiplexing (DWDM) optical transmission systems, cross-phase modulation (XPM) due to Kerr effect causes phase shift on each channel, which will ultimately be transformed to amplitude noise that leads to power penalties. In this letter, the XPM-induced penalty in multi-channel DWDM systems is investigated theoretically and an applied algorithm that can be practically used in engineering design is proposed. 相似文献
9.
The cross-phase modulation (XPM) changes the state-of-polarization (SOP) of various channels and leads to amplitude modulation of the propagating waves in a WDM system. Due to the presence of polarization mode dispersion (PMD), the angles between the SOP of the channels change randomly and cause the modulation amplitude fluctuation random in the perturbed channel. We analytically derive the dynamic equation of the perturbed channel, determine the combined probability density function of the random angle between the SOP of pumps and probe channel and evaluate the effects of PMD on XPM for a 4-channel IM-DD WDM system in terms of BER at bit rate of 10 Gb/s per channel. We also simulate the impact PMD on XPM for a 4-channel WDM system in terms of eye diagram and found that eye opening penalty is 1.85 dB higher when the fiber PMD coefficient increases from 0.5 to 1.5 ps/√km. 相似文献
10.
L. G. Si W. X. Yang X. Y. Lü J. H. Li X. X. Yang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(1):161-166
The authors show the formation of slow temporal vector
optical solitons in a cold lifetime-broadened four-level inverted-Y
atomic system. We demonstrate that Maxwell’s equations for
describing two orthogonally polarised components of a low intensity
signal field can evolve into two coupled nonlinear Schr?dinger
equations, which results in various distortion-free temporal vector
optical solitons, such as bright-bright or dark-dark vector
solitons. These results are produced from the correct balance
between dispersion, self- and cross-phase modulation (SPM and XPM)
effects. We also show that the integrable Manakov model can be
realised by adjusting the corresponding SPM, XPM and dispersion
effects of this inverted-Y atomic system. 相似文献
11.
Ultrawideband monocycle generation using cross-phase modulation in a semiconductor optical amplifier 总被引:1,自引:0,他引:1
We propose a novel scheme to generate ultrawideband (UWB) monocycle pulses based on cross-phase modulation (XPM) of a semiconductor optical amplifier (SOA). The proposed system consists of a SOA and an optical bandpass filter (OBF). Due to the XPM, a continuous wave (CW) probe signal is phase modulated by another optical Gauss pulse in the SOA. The OBF will convert the phase modulation to intensity modulation. A pair of polarity-reversed UWB monocycle pulses is achieved by locating the probe carrier at the positive and negative linear slopes of the OBF. Both cases conform to the UWB definition of the Federal Communications Commission. 相似文献
12.
Impacts of dispersion maps on nonlinear distortion in distributed Raman amplified multi-span systems
The influences of dispersion maps on three major nonlinear effects (SPM, XPM and SRS) in distributed Raman amplified fiber transmission systems with periodic dispersion compensation are numerically investigated at identical nonlinear phase shift. The results show that compared with lumped amplification, distributed amplification tends to enhance the SPM/XPM induced penalties provided per span complete DC is used. However, these performance differences can be canceled out by means of optimal dispersion managements. Moreover, distributed Raman amplification can change the optimal dispersion maps for XPM effects. On the other hand, the impacts of SRS crosstalk are mainly determined by wavelength spacing and walk-off parameter, and the effects of dispersion management are quite limited. For a system with properly designed fiber dispersion characteristics, SRS induced waveform distortion can be well suppressed. 相似文献
13.
XU Lei YAO Minyu LI Yuhua WU Jian CHEN Minghua ZHANG Jianfeng ZHANG Hongming LOU Caiyun GAO Yizhi 《中国光学快报(英文版)》1999,8(4)
200 nm superconticnumm (SC) with high flatness (<3 dB) is demonstrated with subpicosecond optical pulses generated by a passively mode-locked figure-eight-laser. The evolution process of SC under different optical pumping power is observed experimentally. Three sequential evolution stages are found: (1) SC spectrum is asymmetrically broadened due to self-phase modulation (SPM) and group velocity dispersion (GVD). (2) When the broadened spectrum exceeds the zero dispersion point, cross phase modulation (XPM) and four wave mixing (FWM) will cause symmetrical spectrum broadening. (3) stimulated Raman scattering (SRS) causes the spectrum to broaden toward long wavelength quickly when pumping power is intense enough. 相似文献
14.
200 nm Supercontinuum Generated by Subpicosecond Optical Pulses and its Evolution Process Observation 总被引:1,自引:0,他引:1
XU Lei YAO Minyu LI Yuhua WU Jian CHEN Minghua ZHANG Jianfeng ZHANG Hongming LOU Caiyun GAO Yizhi 《Chinese Journal of Lasers》1999,8(4):289-293
Introduction Whenultrashortopticalpulseswithhighintensity(pumpinglight)areinjectedintodispersionshiftedfiber(DSF),duetothenonlineareffectsinfibersuchasselfphasemodulation(SPM),fourwavemixing(FWM),crossphasemodulation(XPM)andstimulatedRamanscatteri… 相似文献
15.
Based on the split-step Fourier method and small signal analysis, an improved analytical solution which describes the cross-phase modulation (XPM) intensity is derived. It can suppress the spurious XPM intensity modulation efficiently in the whole transmission fiber. Thus it is more coincidence with the practical result. Furthermore, it is convenient, because it is independent of channel separation and the dispersion and nonlinear effects interact through the XPM intensity. A criterion of select the step size is described as the derived XPM intensity modulation being taken into account. It is non-uniform distribution method, the simulation accuracy is improved when the step size is determined by the improved XPM intensity. 相似文献
16.
Two-stage adaptive PMD compensation experiment for 10-Gb/s optical communication system 总被引:1,自引:0,他引:1
We report the adaptive compensation experiment of polarization mode dispersion (PMD) for 10-Gb/s non return-to-zero (NRZ) and return-to-zero (RZ) optical communication systems using a two-stage PMD compensator and the monitoring technique based on degree of polarization (DOP) feedback-signals. The DOP monitor has its advantages of bit-rate independent and modulation format independent. The two-stage compensator has the capacity of compensation for the first- and second-order PMD. The compensated differential group delay (DGD) is up to 80 ps, and compensated principal state of polarization rotation rate is 20 ps. The time used for compensation is less than 1 second. 相似文献
17.
理论分析和讨论了基于频域相位共轭技术的交叉相位调制所致信号失真的复原和补偿机理,数值模拟了在交叉相位调制作用下,高斯脉冲在中距相位共轭光纤系统中的传输演化过程.结果表明,频域相位共轭技术能够抑制交叉相位调制对光纤系统中传输信号的损害,复原其所导致的信号失真,并能够同步补偿群速度色散和自相位调制非线性效应所导致的信号失真.合适的初始脉冲时延和初始脉冲啁啾有利于频域相位共轭技术对交叉相位调制所致信号失真的抑制.
关键词:
频域相位共轭
交叉相位调制
色散
自相位调制 相似文献
18.
Phase pre-emphasis is theoretically studied and introduced to reduce peak-to-average power ratio (PAPR) in optical orthogonal frequency division multiplexing (OFDM) systems. In intensity modulated (IM) systems, simulations show noticeable PAPR reductions: 4.14 dB (N = 16) and 15.48 dB (N = 512) in time lens-based OFDM, N is the number of subcarriers. An equation is developed to calculate phase values and is proved to be effective. Optical implementing methods are proposed and analyzed. In a time lens-based OFDM system, phase pre-emphasis reduces fiber nonlinearity and results in a 5.2-dB increase of launch power at the bit error rate (BER) of 10 ?6 . Simulations also show similar PAPR reduction and fiber nonlinearity mitigation in optical inverse discrete Fourier transformer (OIDFT) based OFDM systems. 相似文献
19.
We propose and experimentally demonstrate an all-optical format conversion from two independent non-return-to-zero on-off keying (NRZ-OOK) signals to a return-to-zero quadrature phase shift keying (RZ-QPSK) signal using two cascaded SOAs. Within each SOA, the cross phase modulation (XPM) process is properly controlled by an assistant light. After evaluating its effect on XPM, a suitable power range of assistant light is chosen for the NRZ-OOK to RZ-QPSK format conversion. In the experiment, a RZ-QPSK signal is successfully obtained with opened demodulation eye-diagrams. 相似文献
20.
Wavelength converter plays an important role for increasing the capacity and flexibility of future broadcast network. The cross phase modulation (XPM) based converter has high conversion efficiency at low input power. In order to improve the efficiency and wideband conversion range, the XPM is increase by optimizing the semiconductor optical amplifiers-Mach–Zehnder interferometer (SOA-MZI) configuration. The XPM is improved by increasing the active region length and bias current of the SOA. 相似文献