共查询到19条相似文献,搜索用时 156 毫秒
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光纤光栅非线性时延对啁啾的电视信号的影响 总被引:1,自引:1,他引:0
分析了有线电视系统中,用作色散补偿的光纤光栅因色散抖动对信号载波互调比产生的影响,结果显示色散抖动对有线电视信号互调比的影响随拦动幅度、抖动周期、信道数目的加而增加,信道频率的分布也对其的影响。对光栅的色散特性进行数值估算,发现常耦合系数线性啁啾光栅不能用的有线电视系统中进行色散补偿。 相似文献
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普通单模光纤传输系统的光纤光栅色散补偿研究 总被引:5,自引:4,他引:1
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。 相似文献
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40Gb/s光时分复用传输光纤光栅补偿色散研究 总被引:8,自引:1,他引:7
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。 相似文献
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叠栅条纹信号细分误差的一种动态补偿方法 总被引:2,自引:0,他引:2
缺乏有效的误差补偿方法足制约长光栅测最精度提高的关键原因之一.提出一种动态的误差补偿方法.可以消除由直流漂移、两路信号不等幅和非止交导致的细分误差.其原理是跟踪光栅信号在一个周期上的8个特征值点(正余弦信号的过零点及绝对值交点),从特征值点的幅度值中首先分解出正弦信号的直流漂移误差.对其进行补偿;然后继续跟踪补偿后的信号.从中义能分解出余弦信号的直流漂移误差.再补偿.再跟踪.又能依次分解出不等幅误差和非正交误差.最多只需要3个光栅信号周期,就能对三种误差依次实现补偿.分析了谐波对该方法的影响并提出r改进措施.实验证实了该方法的有效性. 相似文献
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A simple and very precise group delay ripple (GDR) measurement technique for linearly chirped fiber Bragg gratings (CFBGs) is proposed. It is based on real-time optical Fourier transformation of an ultrashort pulse directly induced by the CFBG dispersion. We have experimentally demonstrated highly accurate characterization of the GDR profile of a commercial 10-m-long CFBG with a dispersion of +2000 ps/nm, having achieved a remarkably small standard deviation in our measurements of about 4 ps over a bandwidth of 28 nm. The proposed method has the unique potential to provide real-time GDR monitoring (in the MHz range) by use of commercially available high-speed sampling electronics. 相似文献
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Apodization is a crucial technology for improving the dispersion performance of fiber Bragg gratings (FBGs). In this paper, we focus on how to select an optimal apodization for chirped fiber Bragg gratings and demonstrate a novel apodization selection method capable of choosing the optimal apodization based on the relationship between the bandwidth change and variation in average group delay ripple (GDR). Compared with current approaches, the novel method can select an optimal apodization profile and parameter for FBGs easily and accurately. Two numerical experiments are used to demonstrate the advantages of this method, one exhibits the different performances of five different apodization profiles, the other evaluates the influence of FBG parameters such as grating length, period, chirp, and index change on the apodization performance. 相似文献
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Fernández P. Aguado J.C. Blas J. Durán R. Durán J. De Miguel I. Lorenzo R. Abril E. 《Optical and Quantum Electronics》2004,36(1-3):57-66
We present an optimization process for the apodization strength factor of fiber Bragg grating dispersion compensators. It will be demonstrated that a proper choice of the apodization strength factor results in minimum deviation of the dispersion from the required level, maximum reflection bandwidth and minimum group delay ripple impact, thus leading to a reduction of the Q-factor penalty of the dispersion compensating system. We also discuss the influence of the fiber link length in the determination of the optimum apodization strength factor, taking into account that shorter links minimize the group delay ripple amplitude, whereas the longer ones maximize the bandwidth of interest. It is determined that a fiber link length of ~80 km can balance the requirements of group delay ripple impact and bandwidth. The results obtained through this analysis allow a faster modeling of the Bragg grating parameters in order to achieve an improved spectral performance, as well as a cost-effective fabrication process. 相似文献
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N.M. Litchinitser M. Sumetsky P.S. Westbrook 《Journal of Optical and Fiber Communications Reports》2007,4(1):41-85
Tunable dispersion has been implemented in various technology platforms, including fiber gratings, planar waveguides, thin
film etalons, and bulk optic technologies. This paper will focus on fiber grating based tunable dispersion compensation, because
fiber gratings are at present one of the best developed TDC technologies available. The paper is divided into three parts.
In the first part we describe grating based TDC technologies and discuss their advantages and disadvantages. We focus on thermally
tuned linearly chirped fiber gratings, as these have to date been the most successful grating technology for 40 Gbit/s. We
also compare grating TDCs to two other prominent tunable dispersion technologies: thin film etalons and planar waveguide ring
resonators. In the second section we describe the techniques used to fabricate high performance dispersion compensation gratings
as well as the theory of the primary defect of fiber grating dispersion compensation: group delay ripple (GDR). In the third
section we describe the telecom system related issues for tunable gratings, including characterization of grating performance,
tunability requirements and results from actual system trials using tunable FBGs. 相似文献
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It is proposed that the high dispersion at the transmission band edges of uniform long period gratings (LPG) fabricated on relatively high Δ fibers can be used for efficient dispersion compensation. Since the transmission of LPG varies with length of the grating or refractive index modulation, we show that it is possible to tailor the transmission spectrum to obtain high transmission with constant dispersion and negligible delay ripple over a reasonable bandwidth. Since the proposed structure works in transmission it should be suitable for fiber optic communication links. 相似文献
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This paper presents an overview of fiber Bragg gratings (FBGs) fabrication principles and applications with emphasis on the
chirped FBG used for dispersion compensation in high-speed optical communication systems. We discuss the range of FBG parameters
enabled by current fabrication methods, as well as the relation between the accuracy of FBG parameters and the performance
of FBG-based dispersion compensators. We describe the theory of the group delay ripple (GDR) generated by apodized chirped
fiber gratings using the analogy between noisy gratings and superstructure Bragg gratings. This analysis predicts the fundamental
cutoff of the high frequency spatial noise of grating parameters in excellent agreement with the experimental data. We review
the iterative GDR correction technique, which further improves the FBG quality and potentially enables consistent fabrication
of FBG-based dispersion compensators and tunable dispersion compensators with unprecedented performance. 相似文献
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Phased matched wavelength, effective area, effective Raman gain, and wave guide dispersion are computed from exact numerical solution assuming scalar wave equation in the presence and absence of ripples as imperfections in the refractive index profile in dual cores of single mode fiber Raman amplifier for the first time. It is observed that for larger values of amplitude and lower frequencies, the effective Raman gain increases w.r.t. that calculated with no ripples. However, we assume ripple amplitude up to 5% of core cladding refractive index difference w.r.t. the available data, corresponding to the three ranges of relative ripple amplitudes of 1%, 2%, 3% and ripple frequencies of 1, 2, 3 μm−1. Based on these data, we analyse performance of FRA over frequency shift band of 20–700 cm−1. Uniformity of gain is interestingly seen to be maintained for higher ripple frequency and lower amplitude. However, no prominent effect in coefficient of dispersion and phase matched wavelength is observed within operating range of wavelength. Also, based on available structural parameter, the investigation should find use as a guide to system users to know the limit and promise of existence of ripples. 相似文献