高速光纤通信系统中偏振模色散的补偿方法

偏振模色散(PMD)已成为高速光纤通信系统发展的严重障碍。文章介绍了偏振模色散的概念,对现有的主要偏振模色散的补偿方法进行了分析和比较。指出用保偏光纤(PMF)和偏振控制器(PC)来补偿PMD是目前比较可行的方法,而用光子晶体光纤(PCF)进行PMD补偿的方法也在进一步研究之中。     

偏振模色散的光域补偿方法研究

针对光纤传输中的偏振模色散(PMD)问题,研究和比较了现有PMD的光域补偿方法.利用等效啁啾技术,提出了一种基于啁啾光纤光栅的光域补偿方案,用具有光敏性质的保偏光纤制成啁啾光纤光栅,将其作为PMD补偿器中的时延线,实现了PMD的自适应反馈补偿.实验结果显示,该方案能有效补偿光纤传输中的PMD问题,提高光信号的传输质量.     

偏振模色散补偿的方法

文章指出偏振模色散(PMD)补偿的方法对高速光通信系统的危害,对现有的PMD补偿方案进行了综述,并比较了各种方案的优劣。指出保偏光纤(PMF)补偿PMD是目前比较可行的方法,但更有发展前途的补偿法应该是利用非线性光纤光栅。     

利用高双折射啁啾光纤光栅补偿偏振模色散

利用具有光敏性的保偏光纤，制成高双折射啁啾光纤光栅(FBG)。将其作为偏振模色散(PMD)补偿器的关键器件，进行了一阶PMD补偿实验，补偿量为40～50ps，具有很好的补偿效果。     

高速光纤通信系统中偏振模色散的补偿方法

偏振模色散（PMD）已成为高速光纤通信系统发展的严重障碍。文章介绍了偏振模色散的概念，对现有的主要偏振模色散的补偿方法进行了分析和比较。指出用保偏光纤（PMF）和偏振控制器（PC）来补偿PMD是目前比较可行的方法，而用光子晶体光纤（PCF）进行PMD补偿的方法也在进一步研究之中。     

高速光纤通信系统中PMDE的设计与应用

文章用琼斯传输矩阵法研究了"偏振控制器+保偏光纤"模型仿真器的一阶偏振模色散(PMD)、二阶平行分量、二阶垂直分量及二阶PMD合矢量的统计特性.仿真器的段数越多,其一阶、二阶PMD的统计特性就越接近理论曲线,综合经济因素得出:实验室仿真一阶、二阶PMD特性时采用"3PC+3PMF"模型最为合适.这一结论给下一步的PMD补偿提供了基础.     

保偏光纤偏振模间延迟的放电调整及波片制作

建立了局部放电引起保偏光纤(PMF)两偏振模间相位延迟变化的模型。将熊猫型保偏光纤(P-PMF)和保偏光子晶体光纤(PM-PCF)分别接入萨格纳克干涉仪进行实验研究,发现局部放电使应力型P-PMF的相位延迟变小,使形状型PM-PCF的相位延迟变大,且改变放电电流大小和持续时间可有效改变相位延迟调节量,为调节PMF中两偏振模间相位延迟提供了实用技术。搭建了在线光纤波片制作装置,进行了PM-PCF光纤1/4波片制作的实验研究,实现了0.15°的相位延迟精度。多次实验结果表明,采用该技术可保证约0.24°的相位延迟精度。该技术具有操作简单、成本低等优点,可有效提高光纤波片的相位延迟量精度和制作效率。     

偏振模色散补偿的方法

文章指出偏振模色散（PMD）补偿的方法对高速光通信系统的危害。对现在的PMD补偿方案进行了综述，并比较了各种方案的优劣，指出保偏光纤（PMF）补偿PMD是目前比较可行的方法，但更有发展前途的补偿法应该是利用非线性光纤光栅。     

整段光纤的PMD与各部分的PMD的关系

从无损光波导的传输矩阵出发,研究了两段单模光纤的偏振模色散(PMD)的关系,以及整段光纤与各部分PMD之间的关系,并对结果进行了讨论,指出合理的配置各部分光纤的参数,可以达到偏振模色散补偿的效果.     

高速光纤通信系统中一阶偏振模色散自动补偿技术的研究

偏振模色散(PMD)对10Gbit/s及更高速率的光纤通信系统的影响已不可忽略，因此PMD的补偿技术成为研究的热点问题。本文分析并通过实验验证了PMD引起的脉冲展宽对接收信号频谱的影响，在此基础上提出了一种PMD的补偿技术。在用保偏光纤模拟PMD效应的10Gbit/s的传输线路中实现了一阶PMD的自动补偿。     

高速光通信系统中偏振模色散的补偿

光纤中偏振模色散已成为高速光通信系统增容的主要障碍,文章对现有的各种偏振模色散补偿方法进行了综合评述。认为用偏振控制器与保偏光纤构成的夺模色散自动补偿系统是一种首选方案。     

Novel dispersion compensation method for cross-coupling measurement in PM-PCF based on OCDP

For polarization maintaining photonic crystal fiber (PM-PCF), the cross-coupling measurement can be severely affected by interferogram broadening, due to the large inter-mode chromatic dispersion. In this paper, a novel dispersion compensation method is proposed to mitigate the influence, including a frequency domain algorithm and investigation of the dispersion coefficient for a phase packet in algorithm. A numerical simulation and measurement of birefringence as a function of wavelength reveal that the dispersion coefficient in PM-PCF is much larger than that in PANDA-PM fiber. After compensation, the accuracy of coupling strength measured can be restored and spatial resolution is improved. Experiments show the compensation provides high accuracy with average relative error less than 0.31% and spatial resolution improved 4.1 times.     

单模光纤中椭圆双折射下偏振模色散特性研究

为了分析椭圆双折射对偏振模色散的影响,将模型中的偏振模色散(PMD)矢量及极化相关损耗(PDL)矢量设定为椭圆偏振矢量,应用保偏光纤(PMF)级联模型和蒙特卡罗仿真方法,研究在PDL影响下的PMD统计特性。研究表明,PMD和PDL矢量的椭圆偏振程度对PMD的统计分布和均值大小均会有影响;在椭圆偏振和PDL的联合影响下,PMD的统计分布为Maxwell和Gaussian分布的合分布。研究结果对偏振模色散的测试、补偿和系统设计均具有参考价值。     

2.5 Gb/s偏振模色散自动补偿对偏振模色散容限值的影响

在我国现有的光纤通信骨干网中,绝大部分速率为2.5 Gb/s。今后如在我国现有的2.5 Gb/s网络系统上进行密集波分复用(DWDM)升级,亦需要考虑偏振模色散(PMD)对系统容量升级的影响。采用十段高双折射光纤级联而成的偏振模色散模拟器模拟实际光纤,从信号中提取基带频率分量作为反馈信号,对2.5 Gb/s系统进行了偏振模色散自动补偿实验,并对反馈前后的系统进行了系统代价的测量和比较。实验结果表明,偏振模色散自动补偿能较大幅度地提高系统的偏振模色散容限值。     

Effect of PDL on the DOP feedback signal in PMD compensation

The impact of polarization dependence loss (PDL) on the degree of polarization (DOP) feedback signal in polarization mode dispersion (PMD) compensation is analyzed. PDL affects DOP only in the presence of PMD, and in the presence of PMD and PDL, DOP relates not only to both PMD and PDL vectors but also to the principal states of polarization (SOPs) components of the output signal; on the other hand, it adds new frequency dependence and is no longer independent of system bit rate. The PDL minimum endangering PMD compensation is determined by the step size of the PMD compensating algorithm and the differential group delay (DGD) value in optical fiber systems. DOP could no longer act as the feedback signal in PMD compensation unless the PDL in the fiber system has been effectively eliminated before PMD compensation.     

Reduced phase error of a fiber optic gyroscope using a polarization maintaining photonic crystal fiber

We report the first measurement of the polarization crosscoupling of a 900-m length of quadrupolar-wound sensing coil for the fiber optic gyroscope (FOG) using polarization maintaining photonic crystal fibers (PM-PCFs). The crosscoupling is analyzed with the Optical Coherence Domain Polarimeter (OCDP). Also the polarization extinction ratio (PER) of the PM-PCF coil is measured. For comparison, a standard panda fiber coil with nearly the same length is examined. The results show that PER of the PM-PCF coil is ～10 dB larger than the panda fiber coil, and polarization crosscoupling in the PM-PCF coil is ～10 dB less than in the panda fiber coil. Moreover, based on measurements, a 4-fold reduction in phase error is demonstrated numerically in a FOG made of the PM-PCF coil, compared to the same gyro operated with a similar coil of panda fiber. These findings have important benefits in a higher measurement precision and stability of FOG.     

Automatic compensation of polarization-mode dispersion for 40 Gb/s transmission systems

We present an automatic compensator that effectively mitigates signal distortion due to polarization-mode dispersion (PMD). Accurate compensation is achieved by utilizing a degree of polarization (DOP) monitor with a measurement uncertainty of better than 1% achieved by applying a self-dependent precalibration procedure. The compensation performance at 43 Gb/s was evaluated systematically with respect to both first- and second-order PMD by using a crystal-optical PMD emulator. The compensator extended the tolerable differential group-delay (DGD) limit from 8 to 28 ps, while maintaining the Q penalty below 1 dB. In terms of the average of a Maxwellian-distributed DGD, the PMD compensator enabled transmission for up to 8 ps, or about three times higher than the level tolerated in the uncompensated case. In addition to the compensation performance, we demonstrate successful operation, even for distorted signals with high chromatic dispersion. We believe this capability will be a key enabler for a combined operation with adaptive chromatic dispersion compensators.     

Analytical calculation of pulse broadening in optical higher order PMD compensation

The system performances in second- and third-order polarization mode dispersion (PMD) compensations have been calculated analytically and a proper approach for the higher order PMD compensation has been investigated. The investigation has revealed that the frequency averaged higher order terms of the fiber link's PMD vector should be used as the coefficient vectors in emulating the frequency dependent compensation vector for higher order PMD compensation.     

一种新的自适应偏振模色散补偿前馈方法

提出了一种新偏振模色散（PMD）补偿的方法，直接从被补偿光纤中提取偏振色散矢量的大小和方向信息，根据算法调节偏振模色散补偿器的各参量，使得补偿器的快轴与被补偿光纤的慢轴对准，从而使得偏振模色散得到补偿。这种方法的优点是减少了搜索的自由度。建立了40Gb／s偏振模色散前馈补偿系统，并通过数值模拟．对40Gb／s的非归零（NRZ）码的偏振模色散进行了自适应补偿。通过对补偿前后的眼图、偏振度（DOP）和Q值进行对比和分析，结果表明，这种偏振模色散补偿的前馈方法是非常有效的。