Purely phase-sampled fiber Bragg gratings for broad-band dispersion and dispersion slope compensation

We demonstrated numerically that both the chromatic dispersion and the dispersion slope can be compensated by using purely phase-sampled superstructure fiber Bragg gratings provided both the grating period and the sampling period are chirped linearly along the grating. Adjusting the refractive index modulation and the chirp of sampling function, they can be designed to compensate dispersion of a large number of wavelength-division-multiplexing channels.     

Phased-only sampled fiber Bragg gratings for high-channel-count chromatic dispersion compensation

Binary and multilevel phase-only sampling functions are proposed for the sampled fiber Bragg gratings (FBGs) with high channel count, which require significantly less refractive-index modulation than that does the sampled grating with amplitude sampling. The design using the new simulated quenching optimization with temperature rescaling results in high channel uniformity and minimum energy in the out-of-band channels. The technique can be applied to the sampled FBGs with very high channel count. A five-channel nonlinearly chirped multilevel phase-only sampled FBG for tunable chromatic dispersion compensation is demonstrated.     

利用啁啾光纤光栅的色度色散补偿方案的研究

本文针对高速率光传输系统中的色度色散问题,利用啁啾光纤光栅,设计了后置补偿、前置补偿和混合补偿三种方案并实现了320k。的G．652光纤单信道40Gbit/s的无中继传输,仿真实验结果表明：较之后置补偿和前置补偿,混合补偿具有最好的色散补偿性能。     

光纤布拉格光栅温度补偿研究

提出了一种新颖结构的光纤光栅温度补偿器件,它由两种不同的热膨胀系数的材料组成。利用该器件实现了光纤光栅的温度补偿。在-18~50℃温度范围内光栅波长变化0.028nm,是未补偿光纤光栅的1/23倍。     

啁啾光纤光栅色散补偿方案研究

设计了利用啁啾光纤光栅(CFG)对10Gbit／S光信号进行色散补偿的仿真模拟系统,该模拟系统研究了5种不同的色散补偿方案对系统误码率的影响,选出了最佳的一种补偿方案,模拟研究了入纤光功率对系统误码率的影响,结论是在保持光探测器接收功率不变的条件下,入纤光功率越高,误码率越大．对于最佳色散补偿方案,入纤光功率为6dBm时既能保证较高的传输功率又有较好的误码性能。     

Ramped, unchirped fiber gratings for dispersion compensation

The effective medium method is used to analyze an unchirped fiber grating in which the coupling strength between the light field and grating is monotonically increasing with penetration depth into the grating. The potential use of this type of grating for dispersion compensation in intensity modulated optical systems is discussed. It is shown that, when this type of grating is used in reflection, appropriately designed linearly ramped gratings can be used to compensate fiber dispersion over a wide range of bandwidth-distance product values. In contrast, when the grating is used in transmission, there are strong limits on the bandwidth-distance product     

Analysis of linearly tapered fiber Bragg grating for dispersion slope compensation

We demonstrate that linearly tapered fiber Bragg gratings (FBGs) display nonlinear group delay under strain or stress. The nonlinear group delay of the tapered FBG is analyzed theoretically. Experimental results show a good agreement with the analysis. We are the first to find that linearly tapered FBGs can be used in dispersion slope compensation.     

啁啾光纤光栅补偿光纤色散的研究

啁啾光纤光栅被认为是目前最有实用价值的色散补偿方案之一。分析了啁啾光纤光栅补偿色散的基本原理,从简单模型出发分析了啁啾光纤光栅的色散补偿能力,用数值法研究了啁啾光纤光栅的时延及色散特性,并比较了变迹型与非变迹型啁啾光纤光栅。结果表明要获得较大的色散,要求光纤光栅有较长的长度和较小的啁啾。同时为了消除色散曲线的振荡还必须采取适当的变迹方法。     

Low-coherence interferometric measurements of the dispersion ofmultiple fiber Bragg gratings

We show that the dispersion of multiple fiber Bragg gratings can be obtained from a single low-coherence interferometric measurement. The individual gratings can be identified either from the spatial separation of the interferometric signatures or from the unique wavelength-reflection bands of the gratings     

基于啁啾光纤光栅色散补偿问题的思考

色散已成为光纤长距离、高速率通信中的巨大障碍.鉴于色散补偿光纤插入损耗大、易引入非线性效应等缺点,文章采用啁啾光纤光栅对系统进行色散补偿,克服了以上不足.通过分析啁啾光纤光栅色散补偿的原理,结合理论分析,提出在多通道波分复用系统中使用啁啾光纤光栅,以实现长距离无中继传输.     

啁啾光纤光栅中偏振模色散的研究

首先介绍了不同种双折射率差Δn的光纤制成的啁啾光纤光栅中偏振模色散现象 ,然后说明了光栅中偏振模色散的大小与 Δ n的相关性 ,并阐述了对用于色散补偿作用的啁啾光纤光栅中偏振模色散的消除 (补偿 )方法 ,最后指出利用啁啾光纤光栅中大的偏振模色散对高速光通信系统传输线路中偏振模色散的补偿方法。     

Dispersion compensation of fiber Bragg gratings in 3100 km high speed optical fiber transmission system

By optimizing the fabrication process of the chirped optical fiber Bragg grating (CFBG), some key problems of CFBG are solved, such as fabrication repetition, temperature stability, group delay ripple (GDR), fluctuation of the reflection spectrum, polarization mode dispersion (PMD), interaction of cascaded CFBG, and so on. The CFBG we fabricated can attain a temperature coefficient less than 0.0005 nm/℃, and the smoothed GDR and the fluctuation of the reflection spectrum are smaller than 10ps and 0.5dB, respec-tively. The PMD of each CFBG is less than 1 ps and the dispersion of each grating is larger than -2600 ps/(nm·km). With dispersion compensated by the CFBGs we fabricated, a 13×10 Gbit/s 3100 km ultra long G.652 fiber transmission system is successfully imple-mented without electric regenerator. The bit error rate (BER) of the system is below 10-4 without forward error correction (FEC); when FEC is added, the BER is below 10-12. The power penalty of the carrier-suppressed return-to-zero (CSRZ) code transmission system is only 2.5 dB.     

FBG的衍射光学特性和耦合模理论分析

从衍射光学的角度出发研究了光纤布喇格光栅（ Ｆ Ｂ Ｇ） 的光学特性,进而采用理想模展开的耦合模理论对光纤布喇格光栅的模场分布进行了详细分析,推导出反射率、布喇格反射波长及反射主峰带宽等特性参数的表达式。计算结果表明,理论与实验结果吻合较好,从而验证了理论结果的正确性     

Long-phase error-free fiber Bragg gratings

Stitching errors in the phase mask degrade the spectral response of fiber Bragg gratings fabricated with the phase mask technique. We successfully fabricated a stitching error-free phase mask and applied it to the fabrication of fiber Bragg gratings (FBGs). The gratings have no observable excess sidelobes in the reflectivity and show excellent wavelength selectivity     

Dispersion compensation based on sampled fiber Bragg gratings fabricated with reconstruction equivalent-chirp method

Using uniform phase mask and conventional fabrication technology with submicrometer rather than nanometer precision, a pure third-order dispersion-compensating fiber Bragg grating (DCFBG) and a tunable slope DCFBG are demonstrated with high performance based on the combined reconstruction equivalent-chirp method and an error correction technique. The former DCFBG has a dispersion varying from /spl sim/1000 to /spl sim/-1000 ps/nm in the 100-GHz passband and group delay ripple is less than /spl plusmn/5 ps. The latter has a dispersion slope varying from -150 to 150 ps/nm/sup 2/ within the 3-nm passband, and its group delay ripple is less than /spl plusmn/10 ps.     

Multiple stage dispersion compensation in long haul optical fibresystems using chirped fibre Bragg gratings

Modelling is used to assess the performance of an optical fibre link which has fibre grating dispersion compensators spaced at intervals along its length. A 10 Gbit/s electroabsorption modulator with high positive chirp is shown to transmit in excess of 158 km in normal dispersion fibre using two 2 cm long compensators, incurring a dispersion penalty of only 1.0 dB. Thus the transmission range is improved by a factor of 6.6 over the uncompensated case     

光纤布喇格光栅的制作技术

简单介绍了光纤布喇格光栅（ Ｆ Ｂ Ｇ） 的原理及光学特性,详细阐述了 Ｆ Ｂ Ｇ 的制作技术。此外,详细地描述了采用 Ｋｒ Ｆ 激光器,利用位相掩模法光刻光纤形成 Ｆ Ｂ Ｇ 的实验。此种方法与其他方法相比,有很多的优点。给出和分析了实验的结果     

Lightwave applications of fiber Bragg gratings

Fiber Bragg gratings (FBGs) have emerged as important components in a variety of lightwave applications. Their unique filtering properties and versatility as in-fiber devices is illustrated by their use in wavelength-stabilized lasers, fiber lasers, remotely pump amplifiers. Raman amplifiers, phase conjugators, wavelength converters, passive optical networks, wavelength division multiplexers (WDMs) demultiplexers, add/drop multiplexers, dispersion compensators, and gain equalizers     

Fiber Bragg gratings for dispersion compensation in transmission:theoretical model and design criteria for nearly ideal pulserecompression

We propose a transmission-based dispersion compensator employing an apodized, unchirped fiber Bragg grating (FBG). A theoretical model for dispersion compensation in transmission based on the dispersive properties of the periodic structure is developed. A figure of merit is defined for optimization of the grating parameters for maximum recompression of dispersion-broadened optical pulses in long-haul communication systems. Numerical examples confirm that nearly perfect compensation with very low insertion losses can be achieved for many practical cases of interest     

Custom design of long chirped Bragg gratings: application togain-flattening filter with incorporated dispersion compensation

We present and experimentally demonstrate simple relationships between the refractive index modulation, the chirp-rate or dispersion and the transmission loss through, and reflection of, chirped Bragg gratings, and apply them to the design of a new type of gain flattening filter with incorporated dispersion compensation