利用光子晶体光纤实现10 Gb/s光传输系统的色散补偿

利用光子晶体光纤（PCF）在10Gb/s光传输系统中对普通单模光纤中传输的光脉冲进行了色散补偿，获得了很好的补偿效果。实验中，10Gb／s光脉冲序列经过2.163km普通单模光纤被展宽后．利用26m长光子晶体光纤对其进行色散补偿．补偿后脉冲基本恢复到了初始形状。进一步的理论计算表明，此光纤在C波段20nm波长范围内对普通单模光纤能够实现较好的色散斜率补偿，补偿后剩余色散小于5ps／nm。理论与实验结果表明光子晶体光纤在色散补偿方面具有很大的潜力．在未来光通信系统中将发挥重要作用。     

用于X波段相控阵天线的高速可调光纤延迟线

设计并制作了一种用于X波段相控阵天线的5bit光纤延迟线,采用高速磁光开关和单模光纤级联组成.测试结果显示,该光纤延迟线可实现时间延迟量在0～ 1096ps范围内步进为35.4ps的任意可调,延迟精度小于±2ps,开关切换时间小于30μs.     

先进的光纤光缆技术：光缆网络的革新动向

一种采用１６纤带的高密度光缆目前已经被研制出来，光纤带由涂覆很薄的２００μｍ外径的光纤组成。对于１６芯和８０芯单模光纤连接器而言，平均光损耗分别达到０．２和０．３５ｄＢ。光缆接续时间已减少到目前需要的１／５。通过对纤芯和包层材料的粘度匹配，减少了光纤的结构不完整性损耗。经过改变沿长缆长度方向的布里渊频移，光缆的有效输入功率提高了７ｄＢ。     

对少模大模场多芯光纤的研究与设计

本文利用空分复用思想,提出了一种新的大模场少模多：占光纤（few—mode fiber,FMF）：详述了空分复用的原理、特点以及目前所存在的问题;同时对该大模场少模多芯光纤研究情况进行了说明。研究结果表明,通过在125μm的包层空间中排列纤：＆成圆对称分布的7根纤芯,在保持少模特性的同时,七芯光纤的基模有效面积达到724．21μm^2,且具有良好的弯曲特性。同时当光纤外层涂低折涂覆时弯曲损耗可忽略。涂高折涂覆时,当弯曲半径小于0．6m,该种光纤的弯曲损耗比阶跃型单模大模场光纤小得多,当弯曲半径大于0．4m,该种光纤的弯曲损耗0．03dB／m,同时基模有效面积能保持在735．99μm^2左右。     

单模光纤设计和性能的进展

本文对近年来长波长单模光纤设计和性能的进展作了综合评述。常规单模光纤的零色散波长在1．3μm有匹配包层和压低包层两种折射率分布，设计和选择芯径d、折射率差△、归一化频率V、截止波长λε、建模直径dp等参数时，要使1．3μm的损耗、色散和抗弯能力等性能最佳化。于是考虑波导色散抵消材料色散，使零色散波长移至最低损耗波长1．55μm及其附近窗口。这类光纤称为色散移位和色散平坦单模光纤，其折射率分布有三角形、分隔纤芯和四包层等几种设计。将MCVD、OVD、VAD、PCVD四种工艺的设计和性能列表相互比较。最后总结光纤通信所用单模光纤的现状和前景。     

大芯径双包层单模光纤

本文对芯中折射率为α分布的双包层单模光纤的传输特性作了详细分析和计算,并且考虑了实际光纤制造工艺(MCVD法)中存在的折射率中心凹陷的影响。根据理论计算值,在国内首次成功地制造了大芯径双包层单模光纤,芯径达14～17μm,比通常的单包层单模光纤提高一倍左右,且弯曲损耗也有明显减小。     

微纳纤芯/包层结构大模场单模聚合物光纤设计

提出了一种微纳纤芯/包层结构大模场单模聚合物 光纤。建立了光纤结构模型,在非 弱导近似条件下,根据波导理论,分析了微纳光纤的单模和波导特性;讨论了微纳纤芯直径 、 芯/包层折射率差以及包层直径等结构参数对微纳纤芯/包层结构聚合物光纤的模场分布、有 效 模场直径等导波特性的影响。结果表明,在传输波长λ＝650nm、微纳纤芯直径Dcore＝172μm、包层 直径Dclad＝250μm和芯/ 包层折射率差δn=0.128时,可获得有效模场直径达126.56μm和芯内能流比为10.66% 的大模场单模聚合物光纤。     

采用非零色散位移光纤的骨架式光缆的开发

本文报道了采用G．655非零色散位移光纤（NZDSF）的单层骨架式光缆的开发情况。该缆可以5层4芯光纤带叠加排列,容纳300芯光纤。此类光纤在1530－1620nm范围内具有少量正色散,色散斜率＜0．05ps/nm^2/km。本文测定了试验光缆在C带和L带的机械和光学性能。此类光缆可为经济地建设高比特速率远程传输网络提供大量的有利条件。     

基于侧面抛磨锗芯光纤的折射率传感器

通过抛磨单模-多模-单模(Single mode-Multimode-Single mode,SMS)光纤结构,设计制作一种光纤折射率传感器。多模光纤选用的是纤芯直径为16μm的锗芯光纤,纤芯直径较小,使制作的传感器尺寸较小,从而在传感应用中具有较高的样品利用率。单模光纤纤芯直径为8.4μm,可确保抛磨至多模光纤纤芯附近时单模光纤的纤芯不被破坏。SMS被AB胶固定在玻璃槽内,使得侧面抛磨光纤具有很好的鲁棒性,可重复使用性。制备并侧面抛磨了锗芯光纤长度分别为0μm、23μm、70μm、690μm、2 mm的SMS光纤结构。对产生的传输光谱进行测量,发现前4个样品随着周围环境折射率的增加,谐振波长向长波长处偏移;而前3个样品的折射率测量灵敏度随着锗芯光纤长度的增加而提高。当锗芯光纤长度为70μm时,在1.333~1.367折射率区间内,灵敏度可以达到623.5 nm/RIU。然而,过长的锗芯光纤导致折射率测量灵敏度降低。当锗芯光纤长度为2 mm时,抛磨过程中激发产生了包层模,导致传输光谱复杂、不稳定,而且长波处产生了较大的插入损耗。     

微结构光纤的制造工艺研究

构建了基本的微结构光纤制造系统,初步形成了可行的微结构光纤制造技术路线。利用该工艺技术制造出了全内反射(TIR)型微结构光纤,该TIR型光纤纤芯为9．5／μm,空气孔等效直径为9．8／μm,孔间距为12．3／μm,在1385nm的羟基吸收峰为0．106dB／m,l550nm的衰减为0．008dB／m;该微结构光纤经过显微镜放大和CCD采样到计算机得到的图片表明：光纤中空气孔基本均匀,并且微孔点阵基本呈现正六边形排列。     

Influence of fiber parameters on skew in single-mode fiber ribbons

The influence of fiber parameters on skew has been experimentally clarified by using single-mode 16-fiber ribbons with different fiber parameters. The skews are measured for fibers in 16-fiber ribbons. It is found that not only the relative refractive index difference Δ but also the ratio of the mode field diameter to the core diameter influence the skew. The time of flight is measured for 16-fiber ribbons under several temperature and strain values. Although the time of flight is influenced both by temperature and strain, it is confirmed experimentally that skew is independent of fiber parameters. These results indicate that the skew of a fiber ribbon under a uniform environment can be determined from fiber parameter differences. Previously proposed equations for evaluating the skew are used to design fibers in a fiber ribbon in order to realize fiber ribbons with the desired skew value     

Subscriber single-mode optical fiber ribbon cable technologiessuitable for midspan access

The loop network configuration and high-fiber-count, single-mode optical fiber ribbon cable and jointing technologies which enable a quick response to service demand and offer high reliability in the subscriber network are described. Fiber parameters were chosen for 1.3/1.55-μm wavelength division multiplexing (WDM) transmission, and a 1000-fiber cable composed of 8-fiber ribbons was developed. A mass-fusion splicing technique and a multifiber connector were developed for the fiber ribbon. These techniques were evaluated by constructing an experimental line. It was found that they are highly suitable for midspan access, which is indispensable for the high-fiber-count loop network     

Skew evaluation using two-dimensional refractive-index profile insingle-mode fiber ribbons

The skew of fiber ribbons must be small for high bit rate parallel optical transmission systems. Accurate skew evaluation using fiber parameters is important for this purpose. A simple method, based on the calculus of variations, is proposed for evaluating the skews of fiber ribbons. This method employs only one mode field (LP₀₁ mode) of an ideal step-index fiber as a trial function and a two-dimensional (2-D) refractive index profile. The measured skews of a 16-fiber ribbon composed of fibers with different parameters are compared with calculated values and are found to be in good agreement. The influence on the skew of several refractive index profile deviations (including asymmetric profile deviations) are evaluated using the proposed method. It is found that the asymmetric core profile has a large influence on skew whereas that of the asymmetric core-cladding boundary is relatively small     

Low-rigidity optical fiber ribbon and its application to ultra-high-density cable with bending-loss insensitive fibers

We propose a novel optical fiber ribbon using bending-loss insensitive fibers aimed at tightly and randomly assembling in small core of the cable. Proposed ribbon is designed to be capable of mass-splicing and to suppress local bending and strain increase caused by cabling and cable bending by reducing flexural rigidity against bending under high fiber density assembling. We manufactured the cable with proposed ribbons and achieve the maximum fiber density of a 4.1 fiber/mm² for 400-fiber cable in conjunction with good optical loss and strain characteristics.     

骨架式光纤带光缆用于FTTH的解决方案

将骨架式光纤带光缆用于FTTH的解决方案是将接人用的光纤带光缆中的光纤从机房连到若干交接箱,再接入各住宅单元,并根据住宅单元的不同结构选择所需接入的骨架式光纤带光缆.通过在骨架式光纤带光缆上开启若干分离窗口就可直接抽出需要接入住户的光纤带,而不必按通常的方式将光缆剪断,因无需接续且只需极少量的光缆,加上骨架式光纤带光缆无油膏填充的特点,极大地简化和方便了FTTH的设计和施工.     

Uniform and low polarisation-mode dispersion in 100 fibre ribbonslotted core optical cable

Uniform and low polarisation-mode dispersion, 0.052 and 0.053 ps/√km on the average, has been confirmed in 100 fibre ribbon slotted core optical cable before and after installation, respectively. The cable has been manufactured with standard singlemode fibres having nearly optimised coating structure determined through finite element method analysis conducted to minimise lateral force induced birefringence     

Optical fiber cables for subscriber loops

The use of single-mode optical fiber cables in the local network is discussed. For various network structures, cable constructions with loose buffered fibers, ribbon, and V-groove elements are discussed. For star networks, cables with up to 2000 fibers are described. Cables for bus/star networks are also discussed. Splicing techniques and enclosures are considered. It is concluded that only mass splicing technologies with ribbons will lead to the required results     

Design and performance of very-high-density 60-fiber connectors

High-density, high-count mechanically transferable (MT)-type and multifiber push-on (MPO)-type connectors were constructed by using a monolithic 60-fiber ferrule that aligns five stacked 12-fiber ribbons. The MT- and MPO-type connectors have high packaging densities of 286 and 40 fibers/cm/sup 2/, respectively. We fabricated both types of connector. The average insertion loss of the MT type was 0.30 dB and that of the MPO type 0.70 dB, with and without index-matching material, respectively.     

First measurement of strain distribution along field-installedoptical fibers using Brillouin spectroscopy

Strain distributions along optical fibers in a 1.3-km-long cable before and after installation are measured using Brillouin optical-fiber time domain analysis. The residual strains in the installed optical fibers were found to vary from zero to 0.07%, depending on the conduit configuration and installation procedure. Strain distribution measurements were carried out on a 24-fiber slotted-core type single-mode optical fiber cable for 1.55-μm-wavelength transmission, whose length, outer diameter, and weight were 1.3 km, 14 mm, and 0.18 kg/m, respectively. No clear relation between strain distributions and the fiber configuration in the test cable are found     

Design and performance of ultra-high-density optical fiber cable with rollable optical fiber ribbons

This paper proposes a novel ultra-high-density optical fiber cable that employs rollable optical fiber ribbons. The cable has great advantages in terms of cable weight and diameter, and fiber splicing workability. Moreover, it will be easy to install in a small space in underground ducts and on residential and business premises. The structural design of the rollable optical fiber ribbon is evaluated theoretically and experimentally, and an optimum adhesion pitch P in the longitudinal direction is obtained. In addition, we examined the performance of ultra-high-density cables with a small diameter that employ rollable optical fiber ribbons and bending-loss insensitive optical fibers. The transmission, mechanical and mid-span access performance of these cables was confirmed to be excellent.