一种基于因果分析的光纤Bragg光栅设计方法

从光栅矩阵分析法出发，介绍了一种基于因果分析的光纤Bragg光栅设计方法，并采用该方法设计了用于滤波的均匀光纤Bragg光栅和用于色散补偿的啁啾光纤光栅的结构参数。结果表明，所设计的光栅的分析曲线与目标曲线吻合性很好。     

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.     

基于多子群竞争进化规划算法的光纤光栅设计

从光栅传输矩阵分析法出发,提出了一种基于多子群竞争进化规划算法的光纤Bragg光栅(FBG)设计方法,进而设计了用于滤波的均匀FBG和用于色散补偿的啁啾FBG(CFBG)的结构参数.结果表明,本文设计方法可直接确定FBG的结构参数,在不同的设计精度要求下所设计的FBG分析曲线与目标曲线吻合很好,所采用算法具有比传统的进化规划算法快几10倍的收敛速度和更好的稳定性.     

折射率啁啾调制光纤光栅性能研究

从耦合模理论出发,详细推导出平均折射率调制啁啾系数、初始位置平均折射率调制系数和啁啾光纤Bragg光栅(FBG)周期啁啾系数之间的对应关系,并进行了数值模拟和实验研究。结果表明：通过对平均折射率调制系数进行啁啾控制,可以利用一块相位掩膜版制作出不同色散补偿量的FBG。     

弱非周期性相位取样啁啾光栅的优化方法

取样光栅可以同时对多个信道进行滤波或色散补偿，所以在波分复用(WDM)系统中有广泛的应用，其中周期相位取样光栅是一种很有前途的设计方法，但周期取样的方法会使取样光栅的所有信道具有相同的色散补偿能力。提出设计弱非周期性相位取样啁啾光栅的优化方法，通过引入一组与信道色散补偿量有关的啁啾控制参数，可使不同信道的色散补偿量存在差异。运用该方法设计出弱非周期的取样光栅后，可用传输矩阵法来模拟该光栅的复反射谱，结果显示通过调整啁啾控制参数，可方便地控制不同信道的色散补偿能力，从而能实现对光纤链路色散与色散斜率的同时补偿，而且取样函数的幅度值的起伏则被完全消除。     

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.     

Analysis of fiber Bragg gratings for dispersion compensation inreflective and transmissive geometries

Numerical analysis of the dispersion-compensating properties of fiber Bragg gratings (FBGs) in both reflective and transmissive modes is presented. First, the sensitivity of chirped, reflective gratings to the grating chirp parameter, index modulation, and grating length is examined, showing that apodization provides lower sensitivity to variations in these parameters. Second, we introduce a new transmissive geometry for grating-based dispersion compensation that utilizes the dispersive properties of a uniform Bragg grating in transmission     

Fiber Bragg grating fabrication for dispersion slope compensation

Group-delay dispersion slope causes signal deterioration in long-distance high-data-rate communication systems. We report the fabrication of high-quality apodized and chirped fiber gratings with dispersion slopes as high as -1800 ps/nm/sup -2/ over a 0.7-mn bandwidth-sufficient to compensate for the dispersion slope of >25000-km length of standard fiber at a wavelength of 1550 nm. We believe this is the first time that fiber Bragg gratings have been specifically designed and fabricated for dispersion slope compensation. The fabrication technique uses a standard unchirped phase mask and two scans of the inscribing UV beam.     

高速光通信系统色散补偿技术研究

对色散对光通信系统的影响进行了理论分析；然后以光纤光栅色散补偿和色散补偿光纤为重点，讨论了目前高速光通信系统中的各种色散补偿方案，并对各种方案进行了分析比较，结果表明啁啾光纤光栅色散补偿是最有前途的一种方案；最后对今后色散补偿技术的趋势进行了展望。     

Optical Generation of Binary Phase-Coded Direct-Sequence UWB Signals Using a Multichannel Chirped Fiber Bragg Grating

A novel technique to generate binary phase-coded, direct-sequence ultra-wideband (DS-UWB) signals in the optical domain is proposed and demonstrated. In the proposed system, the wavelengths from a laser array are modulated by a Gaussian pulse, which is sent to a multichannel optical frequency discriminator, to generate a UWB monocycle or doublet pulse sequence with a predetermined phase-code pattern. By tuning the wavelengths of the laser array, or by tuning the states of polarization of the wavelengths, the generated pulse shape and code pattern can be changed. The key device in the system is the multichannel dispersive chirped fiber Bragg grating (FBG), which functions, in combination with a dispersive fiber, as a multichannel frequency discriminator with a step-increased group-delay response, to ensure the generated UWB sequence to have uniform time spacing among the chips and to compensate for the fiber-induced chromatic dispersion. The proposed scheme is experimentally demonstrated. A multichannel chirped FBG is designed and fabricated. Binary phase-coded DS-UWB signals with different code patterns are experimentally generated.      

光纤光栅特性分析

本文介绍了由传输矩阵计算光纤光栅特性的方法,并应用该方法分析了不同切趾形式的Bragg光纤光栅反射谱,变周期光纤光栅的反射谱和色散特性,相移光栅以及取样光栅的反射谱。得出了光栅参量对其特性的影响规律,并用实验验证了切趾光栅、取样光栅的理论分析。     

Interleaved sampled Bragg gratings with concatenated spectrum

We design and demonstrate interleaved sampled Bragg gratings with concatenated spectrum which produce high channel counts with simple design and fabrication. These gratings can be applied in multichannel filtering, dispersion compensation, and many other functions. The devices were implemented as reduction-photolithographically written anti-symmetric Bragg gratings.     

Chirped-pulsed frequency modulation (C-PFM) for fiber Bragg grating sensors multiplexing

In this paper, we present experimental demonstration of using chirped-pulsed frequency modulation technique (C-PFM) in order to increase the multiplexing capability of a multipoint fiber Bragg grating (FBG) sensor network without increasing the hardware complexity of the acquisition system. This technique, extensively used in radar applications, is based on the amplitude modulation of the emitted signal (pulsed) by a chirped frequency signal and on the use of an adaptive filter for the demodulation of the reflected signals. Here, the same principle has been used to develop a FBG multisensor interrogation system by employing a proper frequency chirped modulation. The optical signals reflected from the FBG sensors are first interrogated by using an in-fiber edge filter and discriminated by a novel adaptive numerical filtering. The potentiality and limitation of such technique are discussed. Preliminary experimental results are presented.     

非啁啾光纤光栅在色散补偿中的应用

本文基于均匀布拉格光纤光栅的色散特性和啁啾高斯脉冲的传输演变特性,研究了工作于传输方式的非啁啾光纤光栅的色散补偿性能,讨论了光栅长度,光栅耦合系数等光栅参数以及初始脉宽,初始啁啾等脉冲参量对补偿光纤长度的影响。     

Optimization of Apodized Chirped Fiber Bragg Grating for Dispersion Compensation

Multiwavelength chirped fiber Bragg grating (MCFBG) is a more valuable approach to chromatic dispersion compensation. And adjusting the structure of FBG will optimize the performance of dispersion compensator in 8×10 Gb/s DWDM network, which is proved by simulating calculation.     

WDM系统中啁啾光纤光栅带外色散的影响

对啁啾光栅阻带外的色散特性进行了深入理论分析，在WDM系统中往往需要光栅级联来完成单个光栅不能实现的功能，级联光栅时，前面光栅的阻带外色散要对接续在其后面的光栅产生影响，增大了光栅的时延波动。对光栅级相互间的影响进行了理论分析与实验验证，提出了降低光栅间相互影响的方法是降低调制或光栅切趾，在光栅级联时采用高阶高斯切趾的效果最好。     

高斯脉冲在光纤中传输的光纤光栅色散补偿研究

高斯脉冲在光纤中传输一段距离后，啁啾系数和脉冲宽度均要发生变化，不同啁啾系数和脉冲宽度的高斯脉冲经过啁啾光纤光栅反射后的脉宽压缩特性也不同。本文介绍了啁啾高斯脉冲在光纤中的传输特性以及啁啾高斯脉冲经啁啾光纤光栅反射后的传输特性。理论分析和实验均表明，使用啁啾光纤光栅实现长距离色散补偿时，最佳色散补偿长度与光栅位置有关。     

利用线性啁啾光纤光栅补偿PMD的实验研究

对利用线性啁啾光纤光栅补偿偏振模色散(PMD)进行了实验研究.利用压电陶瓷的压电效应挤压线性啁啾光纤光栅使之产生双折射,用于补偿光通信系统中的偏振模色散.通过改变施加在压电陶瓷上的电压值,可实现对偏振模色散补偿量的线性调谐.实验结果与理论预期基本符合.     

基于啁啾FBG的三角形光脉冲发生器的优化设计

提出了利用啁啾光纤布拉格光栅(FBG)和马赫增德尔调制器产生三角形光脉冲的优化方案.方案采用FBG模拟单模光纤的色散特性,结合光载波抑制调制产生了三角形光脉冲, 并通过仿真分析,选择FBG的长度、调制深度、适当的折射率切趾函数对三角形光脉冲的线性特征进行了优化.仿真结果表明,在同一啁啾系数下,产生的三角形光脉冲的失真程度随啁啾光纤光栅的调制深度增大而增大,光栅长度、折射率切趾函数对三角形光脉冲的影响也比较明显.与现有系统相比,由于将FBG引入系统,省去长距离的光纤,优化方案系统结构更为简单,三角形光脉冲线性特征更好.     

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