高速光通信系统中光纤光栅色散补偿研究

通过对光栅制作过程的优化设计，解决了光纤光栅温度稳定性、纹波系数、带宽、偏振模色 散补偿等关键技术，所制作光纤光栅已经达到温度系数小于00005 nm/℃，带宽大于14 nm，纹波系数小于50 ps，色散量超过 -1000 ps/nm的先进水平. 采用琼斯矩阵本征值法较 精确地测量了光栅的偏振模色散，并对其进行了补偿，光纤光栅色散补偿器的偏振模色散由 补偿前的91406 ps改善为补偿后的01521 ps. 在此基础上，成功地建立了一个稳定可靠 、速率为40 Gb/s，传输链路为122 km G 关键词： 高速光通信系统 普通单模光纤 光纤光栅 色散补偿     

基于非线性啁啾光纤光栅实现的色散可调谐

从原理上证明了一种基于非线性啁啾光纤光栅以及光纤光栅的温度特性的色散可调谐方案.实验证明在25.5℃的温度变化范围内,光纤光栅对1550.43nm波长的色散补偿量从759.1ps/nm上升到1659.9ps/nm,色散调谐范围达到900ps/nm,这个方案具有对补偿波长和特定补偿波长所需要的色散补偿量同时进行调谐的特点.     

40Gb/s光时分复用传输光纤光栅补偿色散研究

用精密扫描掩模法写入宽阻带啁啾光纤光栅,掩模板背面两端各10％长度处镀有按4阶高斯函数透过率的膜,写入的啁啾光栅的时延纹波最大值为20ps。为减少写入光纤光栅的偏振模色散,研制了新的低偏振模色散光纤光栅补偿写入法。采用补偿写入法前的平均微分群时延为9．1406 ps;采用补偿写入法后的平均微分群时延为0．1521 ps。并利用低偏振模色散光纤光栅对40Gb／s光时分复用系统在普通G．652光纤传输122km的色散进行了补偿实验,功率代价为1．5dB。     

利用啁啾光纤光栅色散特性实现波长可调谐的主动锁模掺铒光纤环行腔激光器

在环形腔主动锁模光纤激光器中引入啁啾光纤光栅，利用啁啾光纤光栅的大色散特性，通过调节调制频率，实现波长调谐，调谐范围2nm。所得脉冲为重复频率2．5GHz，脉宽约60ps的正啁啾脉冲，。     

啁啾光纤光栅的温度调谐特性研究EI北大核心CSCD

根据啁啾光纤光栅的温度可调谐性这一原理,提出通过控制啁啾光纤光栅的温度,改变其色散量,从而获得最小输出脉宽的方案,并通过实验验证了这一想法的可行性。利用啁啾光纤光栅作为啁啾脉冲放大(CPA)系统中的脉冲展宽器,用空间光栅对作为脉冲压缩器,通过压缩器为脉冲提供的负色散来补偿展宽器为脉冲引入的正色散。利用自相关仪测量压缩输出脉冲宽度随温度的变化情况,间接反映啁啾光纤光栅色散量随温度的变化情况。从实验所得数据可以得知,当温度从-7℃上升到50℃时,脉宽从1057fs先下降到764fs后又上升到910fs,共变化了439fs。在此过程中,随温度的上升,啁啾光纤光栅的色散由补偿不足变为过补偿。     

色散补偿和色散位移光纤实现光脉冲压缩

根据超短光脉冲在光纤中传输的非线性薛定谔方程，模拟了不同色散参量情况下色散补偿和色散位移光纤对增益开关半导体激光器产生的光脉冲的压缩，给出了光脉冲在经过色散补偿光纤前后的啁啾曲线。结果表明，使用色散参量D分别为-150，-180和-20ps/(nm·km)的色散补偿光纤可以实现其他脉冲压缩方法的压缩效果，最大压缩因子达到6.09，但色散参量越大，所需光纤长度就越短。此外，脉冲经过色散补偿光纤后线性啁啾几乎为零。还利用色散位移光纤对脉冲进行孤子压缩，脉冲宽度由最初的45ps减小到1.23ps。指出采用这2种光纤相结合的方法可以对光脉冲实现高效压缩。     

利用啁啾光纤光栅进行色散补偿的研究

分析了由于光纤的色散引起的脉冲展宽,并介绍了啁啾布拉格光纤光栅进行色散补偿的基本原理。２－５Ｇｂ／ｓ、１００ｋｍ 色散补偿的实验结果表明,利用啁啾光纤光栅进行色散补偿是一种切实可行的色散补偿方案。     

普通单模光纤传输系统的光纤光栅色散补偿研究

通过系统分析光纤光栅的耦合模理论 ,探索、优化光纤光栅的制作过程 ,研制了满足ITU T建议波长的优质光纤光栅。用双透镜和扫描移动平台结合相位掩膜板研制的光纤光栅分别成功实现了 4× 10Gb/s 4 0 0km和4× 10Gb/s 80 0km普通单模光纤传输系统的色散补偿 ,功率代价均小于 2dB ,且最佳功率代价为负值。同时对4× 10Gb/s 80 0km普通单模光纤传输系统的偏振模色散实施长时间的监测 ,系统偏振模色散小于 10 ps,提出了发展 10Gb/s的光通信系统更符合目前我国国情的见解。     

实用化线性啁啾光纤光栅的研制

我们用等周期的相位掩模板,摘用光纤倾斜曝光或二次曝光的方法,做出啁啾光纤光栅,色散量可达170ps/nm。并用在10Gb/s高速光纤通讯系统上,成功地实现了180公里的信号传输的色散补偿。     

光纤光栅偏振模色散的测量及补偿研究

介绍了光纤光栅的偏振模色散测量，并利用一段偏光纤对光纤光栅的偏振模色散进行补偿，效果良好。在40Gb/s、60km光纤光栅色散补偿系统中，加入保偏光纤对光纤光栅的偏振模色散进行补偿前后的测试结果表明，误码率为10^-10时，系统的功率代价由1.21dB改善为0.46dB。     

Timing jitter induced by intrachannel interactions in optical fiber communication systems using CFG as dispersion compensator

In this paper, a theoretical model is proposed for the analysis of timing jitter induced by intrachannel interactions in optical fiber communication systems using chirped fiber grating (CFG) as dispersion compensator. And for the first time, the impact of group-delay ripple (GDR) on timing jitter is taken into account in detail, theoretically and numerically. Results show that the GDR may increase or decrease the timing jitter of certain pair of adjacent pulses, deciding by the ripple parameters. The maximum influence will be obtained when ripple period is about 2/5 of the input pulse width. In practical systems, the GDR enhance the timing jitter for some adjacent pulses while reduce it for some other adjacent pulses, depending on the pulse pattern and the GDR parameters. In our simulation, the GDR guarantees a 3.04 ps increase of the standard deviation of the timing jitter.     

Investigations on order and width of RZ super Gaussian pulse in pre-, post- and symmetrical-dispersion compensated 10 Gb/s optical communication system using standard and dispersion compensating fibers

We show the effect of varied order and width of super Gaussian pulse at 10 Gb/s in dispersion compensated optical communication system. The optical communication system consists of standard single-mode fiber of 16 ps/nm/km of a certain length, whose dispersion is compensated using pre-, post- and symmetrical-dispersion compensation schemes with proportionate length dispersion compensating fiber of −80 ps/nm/km. Performance of these three compensation schemes is compared at 14 dBm values of Er-doped fiber amplifiers (EDFA) power at 1st, 2nd and 3rd order RZ super Gaussian optical pulse. The pulse width, full width at half maximum (FWHM) is also varied from 5 to 30 ps to highlight the optimum performance. The graphical results obtained show a relationship among the attributes pulse width, order of RZ super Gaussian optical pulse and dispersion compensation scheme implemented. It shows that to decrease BER and timing jitter in the system, smaller width and 3rd order super Gaussian pulse should be used. It is recommended that to decrease dependency of BER and timing jitter in the communication system on the pulse width i.e. FWHM, the symmetrical compensation scheme should be implemented.     

利用光纤-光栅对1.06μm皮秒光脉冲压缩

本文报道了利用光脉冲在10m单模光纤中传播所产生的自相位调制(SPM)、互相位调制(XPM)、群速色散(GVD)和受激喇曼散射(SRS)的共同作用,实现光脉冲光谱和时间加宽,经光栅对线性啁啾补偿后,将脉宽15ps的1.06μm光脉冲压缩至小于6ps,能量大于100nJ,压缩比>2.5。     

Group-delay ripple correction in chirped fiber Bragg gratings

Group-delay ripple (GDR) introduced by systematic and random errors in chirped fiber Bragg grating fabrication is the most significant impediment to application of these devices in optical communication systems. We suggest and demonstrate a novel iterative procedure for GDR correction by subsequent UV exposure by use of a simple solution of the inverse problem for the coupled-wave equation. Our method is partly based but does not fully rely on the accuracy of this solution. In the experiment we achieved substantial reduction of the low-frequency group-delay ripple, from +/- 15 to +/- 2 ps, which resulted in dramatic improvement of the optical signal-to-noise-ratio system penalty, from 7 to less than 1 dB, for a chirped fiber Bragg grating used as a dispersion compensator in a 40-Gbit/s carrier-suppressed return-to-zero system.     

Study on the 4×10 Gb/s,400 km dispersion compensation by chirped optical fiber grating

In this paper, the dispersion compensation for 4×10 Gb/s, 400 km G.652 fiber by chirped optical fiberBragg grating (FBG)is introduced.For the first time,we have measured and compensated the polarizationmode dispersion(PMD)of FBG, which in each channel is less than 1.1 ps.When the bit crror rate(BER)is 10~(-10)and the bit error is zero, the transmission power penalty of each channel is less than 2 dB, andthe best, result is negative which means that the receiver sensitivity is increased after transmission.     

掺Yb3+光纤F-P腔被动锁模激光器的实验研究

 掺镱(Yb³⁺光纤被动锁模激光器谐振腔采用线性腔结构，腔内插入二分之一波片和偏振分束器引入偏振旋转，结合半导体可饱和吸收镜的自起动，实现稳定的被动锁模运转。腔内插入光栅对，提供负的群速度色散，以补偿光纤所带来的正色散，达到压缩脉宽的目的。当泵浦功率为300 mW、光栅对的距离为10 cm时，获得稳定的锁模运转，锁模输出功率28 mW，脉冲重复频率20 MHz，输出光谱宽度达15 nm，按脉冲变换极限公式，其脉冲时间宽度与频带宽度的乘积为0.315计算，脉宽可达100 fs以下。     

利用遗传算法优化线性啁啾光栅性能

针对制作町用于40 Gb/s全光色散补偿的宽带线性啁啾光栅时出现带内群时延纹波波动较大等问题.提出了一种通过设计和改变切趾函数的参量来优化线性啁啾光栅的新方法.该方法实现简单.只需根据需要设计具有不同滚降特性的切趾函数,同时利用遗传箅法来优化切趾参量.结合传输矩阵法经过200代获得了低带内时延纹波的线性啁啾光栅.数值结果验证了采取非对称分段切趾法在保持反射谱宽和平坦性的同时可以抑制带内群时延纹波的优越性.利用该方法制作了反射谱工作带宽为1.06 nm、时延纹波不超过45.60 ps、可用于大容量密集波分复用系统(DWDM)色散补偿的线性啁啾光纤光栅.     

On duty cycle selection of RZ optical pulse to optimize the performance of dispersion compensated 10 Gbps single channel optical communication system using dispersion compensating fibers

We present results for duty cycle selection of optical RZ pulse to optimize the performance in 10 Gbps single channel dispersion compensated optical communication system. The system has link length of 240 km with two spans. Each of the spans consists of 120 km standard single mode fiber (SSMF) of 16 ps/nm/km, whose chromatic dispersion is compensated using pre-, post- and symmetrical-dispersion compensation schemes by 24 km dispersion compensating fiber (DCF) of −80 ps/nm/km. The performance of the three compensation schemes is compared by taking 8, 10, 12 and 14 dBm Er-doped fiber amplifier (EDFA) power levels in the link with a duty cycle range (0.1-0.9) of RZ optical pulse. The graphical results obtained show a relationship among the duty cycle, EDFA power and dispersion compensation scheme which predicts the best performing duty cycle case. To optimize performance of the system, we recommend in general, duty cycle less than 0.3 and EDFA power below 8 dB irrespective of compensation scheme. However, with post compensation duty cycle less than 0.7 and EDFA power below 12 dBm give optimum performance. The results conclude that for the high value of duty cycle, post dispersion compensation scheme should be used.