对40 Gb/s OTDM系统中光纤光栅色散补偿器进行偏振模色散补偿的研究

改变光纤光栅紫外曝光系统 ,在相位掩模板后插入一个旋转装置 ,使得光纤在制作过程中可以进行某种旋转。通过这种方法制作的光纤光栅偏振模色散减小到平均差分群时延 (DGD)约为 0 2ps,而没加旋转制作的光纤光栅平均DGD约为 18 2 ps。采用两个这种低偏振模色散 (PMD)的光纤布拉格光栅 (FBG) ,成功地在 4 0Gb/s光时分复用 (OTDM)系统中补偿了约 2 0 4 0 ps的色散 ,该系统在经过 12 2km普通单模光纤传输后 ,未发现PMD的影响 ,传输功率代价小于 1 4dB。     

A New Idea and Technique of Fiber Gratings and Photodetectors in Broad-band Fiber Communication Systems

Contents of this thesis are supported by the National Natural Foudation of China under Contract No.69625101, and the item is named "Tunable Optical Technology in Wavelength Division Multiplexing (WDM)" and is under charge of Professor Ren Xiaomin. They are also supported by subject 307 in National Program "863": i.e., RCE photodetectors (PDs) used in Wavelength Division Multiplexing. Fiber Bragg Gratings (FBGs) have emerged as important optical fiber passive components in a variet…     

Chirp光纤光栅色散补偿理论及实验

分析了 Ｃｈｉｒｐ光纤Ｂｒａｇｇ光栅进行色散补偿的基本原理,２０ Ｇｂ／ｓ、１００ ｋｍ色散补偿的实验表明,利用Ｃｈｉｒｐ光纤Ｂｒａｇｇ光栅是一种优选的色散补偿方案。     

Design and Fabrication of Fiber Bragg Gratings With V-Shaped Dispersion Profile

We propose a new type of fiber Bragg grating (FBG) with a V-shaped dispersion profile. We demonstrate that such V-shaped FBGs bring advantages in manipulation of optical signals compared to conventional FBGs with a constant dispersion, e.g., they can produce larger chirp for the same input pulsewidth and/or can be used as pulse shapers. Application of the proposed V-shaped FBGs for signal prechirping in fiber transmission is examined. The proposed design of the V-shaped FBG can be easily extended to embrace multichannel devices     

Long-haul soliton WDM transmission with periodic dispersioncompensation and dispersion slope compensation

A 20 Gb/s-based soliton wavelength division multiplexed (WDM) transmission experiments using periodic dispersion compensation and dispersion slope compensation were demonstrated. Accumulated dispersion slope was compensated with two methods. The first method was periodical individual dispersion compensation. By using this technique, 60 Gb/s (20 Gb/s×3 WDM) transmission over 8000 km was demonstrated. The second method was the use of a dispersion-flattened transmission fiber. 160 Gb/s (20 Gb/s×8 WDM) transmission over 4000 km using periodically dispersion compensated dispersion-flattened fiber was also demonstrated     

A study on the relationship between DWDM transmission performance and chromatic dispersion

In this letter, we numerically study the relationship between 40-Gb/s-based dense wavelength-division-multiplexing (DWDM) transmission performance and chromatic dispersion in two different transmission lines. We show that the optimum chromatic dispersion region for improving the DWDM transmission performance varies with the type of transmission line. We also show that a hybrid transmission line has a greater potential to resist any change in the dispersion slope compensation characteristics than a single fiber transmission line with a dispersion compensation fiber module. Finally, we show that chromatic dispersion of more than 12 ps/nm/km in a hybrid transmission line is optimum for a 40-Gb/s-based DWDM transmission system by taking the design of a dispersion compensating fiber into account.     

S波段分布式光纤拉曼放大器的实验研究

在S波段对3种不同配置的色散补偿型分布式光纤拉曼放大器(FRA)进行了研制。实验证明：5km DCF-50km G652光纤色散补偿型分布式FRA的增益和噪声特性优于50km、G652-5km DCF光纤和25km G652-5km DCF-25km G652光纤色散补偿型分布式FRA。测量了5km DCF-50km G652光纤色散补偿型分布式FRA的增益光谱和噪声谱。存DWDM光纤传输系统中,色散补偿分布式FRA对S波段1520nm光谱波段2个光谱间隔为0．262nm(频率间隔为34．1GHz)信号信道光谱的传输特性优于50km G652正色散FRA和5km DCF负色散FRA。     

基于DCF长距离光纤通信系统的色散补偿

通过介绍光纤色散的产生及其对传输系统的影响,引出了色散补偿技术.在多种色散补偿方法中,侧重探讨了色散补偿光纤(DCF)技术.基于DCF在标准单模光纤上传输2245 km的情况下进行了研究,获得了一些对实际色散补偿系统有参考价值的结论.     

基于非线性啁啾光栅和波长扫描的ROF系统

为了降低光信号在不同传输距离产生的色散对光载射频(ROF)(光载无线电)传输系统的信号质量的影响,提出了一种基于静态非线性啁啾光纤光栅(NLCFBG)和动态波长扫描相结合的可调谐色散补偿ROF传输系统方案。在对所提出系统方案进行理论分析的基础上制作了NLCFBG,并对ROF传输中的可调谐色散效果进行半实物仿真,分析和比较了有无光栅色散补偿时系统的传输性能;验证了此方案对不同传输距离、不同激光频率以及不同射频载波频率的光纤传输系统色散补偿性能。     

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.     

Complete dispersion compensation for 400-fs pulse transmission over10-km fiber link using dispersion compensating fiber and spectral phaseequalizer

We have demonstrated essentially complete dispersion compensation for 400-fs pulses over a 10-km fiber link using dispersion compensating fiber and a programmable femtosecond pulse shaper functioning as a spectral phase equalizer. The pulse shaper impresses adjustable quadratic and cubic phases onto the spectrum and removes all the residual dispersion and dispersion slope in the dispersion compensated fiber link. Our work shows that the pulse shaper technique provides a powerful and convenient tool for programmable fiber dispersion compensation over broad optical bandwidth. This allows distortion-free femtosecond pulse transmission over a fiber link in excess of 10 km without requiring the exact trimming of the dispersion-compensating fiber     

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     

Experimental evaluation of chromatic dispersion distortion inoptical CPFSK transmission systems

Receiver sensitivity degradations due to fiber chromatic dispersion without chromatic dispersion compensation in multigigabit optical continuous-phase frequency-shift-keying (CPFSK) transmission systems are evaluated experimentally and theoretically. Transmission distance limited by the chromatic dispersion of 15 ps/nm/km is estimated to be 130 km at 5 Gb/s and 33 km at 10 Gb/s     

All-Raman ultralong-haul single-wideband DWDM transmission systems with OADM capability

In this paper, we present a comprehensive experimental investigation of an all-Raman ultrawide single-band transmission system for both 10 and 40 Gb/s line rates. Enabling technologies include forward-Raman pumping of the transmission fiber, counter-Raman pumping of the fiber spans and dispersion compensation modules, wideband dispersion, and dispersion-slope compensation, and modulation formats resistant to both linear and nonlinear impairments. Ultralong-haul (ULH) 128/spl times/10 Gb/s return-to-zero (RZ) and ultrahigh-capacity (UHC) 64/spl times/40 Gb/s carrier-suppressed (CS) RZ transmission are demonstrated for commercially deployed fiber types, including both standard single-mode fiber (SSMF) and nonzero dispersion shifted fibers (NZDSF). The span losses of 23 dB (NZDSF) and 20 dB (SSMF) are consistent with those encountered in terrestrial networks. The optical reaches for 10 Gb/s rate are 4000 km (NZDSF) and 3200 km (SSMF). Using the same distributed Raman amplification (DRA) scheme, UHC over 2.5 Tb/s at a 40-Gb/s per channel rate is also demonstrated for all of the tested fiber types and for optical reaches exceeding 1300 km. We then study the impact of including optical add/drop modules (OADMs) in the transmission system for both 10 and 40 Gb/s channel rates. System performance is characterized by the system margin and the transmission penalty. For all of the experiments shown in this paper, industrial margins and small transmission penalties consistent with operation in commercially deployable networks are demonstrated, showing the feasibility of practical implementation of all-Raman amplified systems for ULH and UHC optical backbones. Attractive features of single-wideband transmission enabled by DRA include simplicity of design, flexible gain and gain-ripple control, good noise performance, and a small system footprint.     

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。     

Broad-band mid-span spectral inversion without wavelength shift of1.7-ps optical pulses using a highly nonlinear fiber Sagnacinterferometer

We demonstrate broad-band mid-span spectral inversion without wavelength shift of short optical pulses using a highly nonlinear fiber Sagnac interferometer. The 1.55-μm optical pulses with a 1.7-ps pulsewidth are transmitted over 40 km of standard fiber, showing the suitability of this technique for broad-bandwidth second-order dispersion compensation in high-bit-rate optical fiber transmission systems     

Repeaterless 10.7-Gb/s DPSK Transmission Over 304 km of SSMF Using a Coherent Receiver and Electronic Dispersion Compensation

Record repeaterless transmission of differential phase-shift keying (DPSK) at 10.7 Gb/s over 304 km of standard single-mode fiber (SSMF) is demonstrated using a coherent optical receiver and electronic dispersion compensation. This is the longest repeaterless 10-Gb/s transmission over SSMF in the absence of Raman amplifiers. The high receiver sensitivity and the high tolerance to nonlinearities of DPSK allow us to overcome a total link loss of 58 dB with a 3-dB system margin. Coherent detection enables linear electrical dispersion compensation and avoids the use of optical dispersion compensation.     

Dispersion compensation optical fiber modules for 40 Gbps WDM communication systems

Dispersion compensation was originally proposed to equalize pulse distortion.With the development of wavelength division multiplexing (WDM) techniques for large capacity optical communication systems,dispersion compensation technologies have been applied into the field.Fiber-based dispersion compensation is an attractive technology for upgrading WDM communication systems because of its dispersion characteristics and good compatibility with transmission optical fibers.Dispersion compensation fibers and the modules are promising technologies,so they have been receiving more and more attention in recent years.In this work,high performance dispersion compensation fiber modules (DCFMs) were developed and applied for the 40 Giga bit-rate systems.First,the design optimization of the dispersion optical fibers was carried out.In theory,the better the refractive index profile is,the larger the negative dispersion we could obtain and the higher the figure of merit (FOM) for the dispersion optical fiber is.Then we manufactured the fiber by using the plasma chemical vapor deposition (PCVD) process of independent intellectual property rights,and a high performance dispersion optical fiber was fabricated.Dispersion compensation fiber modules are made with the dispersion compensating fibers (DCFs) and pigtail fibers at both ends of the DCFs to connect with the transmission fibers.The DCFMs present the following superior characteristics:low insertion loss (IL),low polarization mode dispersion,good matched dispersion for transmission fibers,low nonlinearity,and good stability for environmental variation.The DCFMs have the functions of dispersion compensation and slope compensation in the wavelength range of 1525 to 1625nm.The experiments showed that the dispersion compensation modules (DCMs) met the requirements of the GR-1221-CORE,GR-2854-CORE,and GR-63-CORE standards.The residual dispersions of the G.652 transmission lines compensated for by the DCM in the C-band are less than 3.0ps/nm,and the dispersion slopes are also compensated for by 100%.With the DCFMs,the 8×80km unidirectional transmission experiments in the 48-channel 40Gbps WDM communication system was successfully made,and the results showed that the channel cost was smaller than 1.20dB,without any bit error.     

10 Gb/s 120-km Bidirectional Repeaterless Transmission over Single-Mode Fiber

A successful repeaterless 10 Gb/s bidirectional transmission experiment is demonstrated at the 1550 nm wavelength through 120 km of single-mode fiber. Fiber chromatic dispersion compensation in both transmission directions is realized by insertion of the same dispersion compensating fiber in the transmission fiber span. Excellent long-term error rate performance (BER < 10-¹⁴) is achieved by suppression of the Rayleigh backscattered signal power with low loss narrow-band fiber grating reflection filters.     

Design theory of long-distance WDM dispersion-managed transmissionsystem

This paper describes a novel design theory of long distance wavelength division multiplexed (WDM) dispersion-managed optical transmission systems. Assuming that the transmission distance, bit rate, and number of WDM channels are initially known, we investigate the optimum dispersion allocation and input power per channel to achieve the minimum channel spacing. Based on the design guidelines for single-channel and multichannel systems, we establish the optimal design strategy. Details of the design procedure are demonstrated for 2.5-, 5-, and 10-Gb/s 10000 km WDM systems by using computer simulations. Next, we study the impact of the fiber dispersion slope on the usable wavelength span, and show that the attainable capacity of the representative 5-Gb/s 10000 km WDM system employing the postcompensation scheme can not exceed 100 Gb/s. Finally, we propose several techniques to approach the ultimate capacity of the WDM system and show that up to 1 Tb/s (200×5 Gb/s) 10000 km system can be implemented without utilizing the in-line dispersion slope compensation scheme. We also discuss the 10 Gb/s-10000 km WDM system employing in-line dispersion slope compensation