国外塑料光纤研究动向

聚甲基丙烯酸甲酯芯塑料光纤,是美国杜邦公司于1964年首先研制成功的,1966年商品化。1972年日本也实现了商品化。初期的制品由于损耗大(>1000dB/km)未受重视。1977年,杜邦公司报道了氘化聚甲基丙烯酸甲酯芯塑料光纤的损耗为180dB/km(690nm波长下),日本三菱人造丝公司也开发出300dB/km(570nm)的聚甲基丙烯酸甲酯芯塑料光纤。从此,由于塑料光纤已能用于短距离的光传输,而且与无机光纤相比,它又具有价格低、易加工、耐冲击、轻     

塑料光纤及其制备方法

一、引言1964年,美国Du pont公司首先研制成功以聚甲基丙烯酸甲酯为纤芯的塑料光纤。1966年,日本开始在市场上出售。1972年,实现了商品化。当时,塑料光纤的传输损耗为数千dB/km。因此,仅限于在显示和灯光监视器等很狭窄的领域内使用。     

高分子敏感材料及其应用(Ⅱ)

它是一种新型的光纤材料,应予以重视。从目前的情况来看,损耗小、耐热性良好的石英光纤仍然是光纤传感器的主要材料。但高分子光纤具有可挠性、重量轻、易加工等优点,因此,它也是一种性能优良的光纤材料。目前,主要应从材料的结构、配方和纯度等方面来研究如何降低损耗,现已研制出损耗为100dB／km的高分子化纤。高分子化纤的芯线主要用聚甲基丙烯酸甲酯,包层用氟系聚合物。     

用于短距离通信的塑料光纤技术

介绍了塑料光纤的开发历史和现状,从短距离通信的角度,介绍了聚甲基丙烯酸甲酯（ＰＭＭＡ）的塑料光纤,全氘化塑料光纤和全氟化塑料光纤的损耗,大数值孔径和小数值孔径阶跃型塑料光纤以及渐变型塑料光纤的带宽。另外,介绍了用于高速塑料光纤通信系统的光源和光检测器及其开发现状。     

氟化物玻璃光纤在非通信领域的应用

氟化物玻璃光纤在可见光到中红外波段具有极高的透过,它在3μm左右理论损耗可降至10~(-3)dB/km,是实现远距离无中继站通信最有希塑的超低损耗光纤材料。近十年来,各国相继开展了超低损耗氟化物玻璃光纤的研制,使光纤最低损耗降至0.7dB/km(长     

“熔接补偿剪断法”标定标准光纤的损耗

利用“熔接－OTDR实测熔接头损耗－补偿（FCCB）”实现了无二次连接／对准的剪断法光纤损耗测量,这种改进的FCCB将光纤损耗测量的不确定度提高到优于0．015dB/dB(2σ）。     

基于SOI光波导的损耗测试与优化

利用电子束光刻技术,制备了带有氧化硅包层的SOI光波导结构,对其传输模态及损耗进行了详细的理论分析,并分别对波导的传输损耗和耦合损耗进行了测试.测试结果验证了单模传输模态时的传输损耗较低,在波导层上添加覆盖层可以将波导传输损耗降低至3.96dB/cm,利用光栅垂直耦合可以大大降低光纤-波导的耦合损耗,耦合效率可以达到32.7%.     

一种高双折射低限制性损耗光子晶体光纤设计

本文设计了一种适用于长距离光纤通信的新型光子晶体光纤。该光纤包层内椭圆形和圆形空气孔呈交错排列,纤芯两侧为两个小椭圆空气孔。利用有限元分析方法对所设计光纤的传输特性进行分析并对其结构进行了优化,确定了最佳结构。结果表明,波长为1550 nm时,此新型光子晶体光纤在最佳结构下可提供高达3.51×10^-2的高双折射和低至1.5×10^-9 dB/m的限制性损耗。与现存的引入椭圆形空气孔的光子晶体光纤相比,本文中的光子晶体光纤的双折射系数有较大提高,限制性损耗系数降低了5个数量级。另外,本文还详细研究了光子晶体光纤的色散随光子晶体光纤结构的变化以及其布里渊增益特性,并分析了其可制造性。基于其高双折射和低限制性损耗特性,此种光纤可应用于长距离光纤通信系统。     

用于氟化镓铟高数值孔径光纤的氟磷酸盐和氟锆酸盐包层玻璃

为了得到用于1．3μm光通讯窗口掺镨氟化镓铟（PGICE）高数值孔径光纤，本文报道以ZrF4。－BaF2－LaF3－AlF3－Na（Li）F－PbF2[ZBLAN（Li）Pb]和NaPO3－BaF2－ZnF2－PbF2（FPG）玻璃作为包层材料研究了芯和包层玻璃在物理性质和化学组分上的匹配性差热扫描（DSC）和电镜（SEM）分析表明PGICA/ZBLAN(Li)Pb虽在物理性质上匹配但在化学组分上不匹配．其芯-包展界面生成不稳定相；只有PGICZ/FPG具有良好的物理、化学配合性，可成功地拉制出高数值孔径光纤．     

低损耗离子交换玻璃基光波导制备与分析

考虑到离子交换和离子扩散工艺的特殊要求, 设计并熔制了适合于离子交换工艺的硅酸盐玻璃材料SiO₂-B₂O₃-Al₂O₃-R’O-R₂O（R’=Ca, Mg; R=Na, K）. 采用Ag⁺/Na⁺熔盐离子交换和电场辅助离子扩散工艺在这种玻璃材料基片上获得了掩埋式条形光波导. 光学显微镜和电子探针分析表明高折射率的Ag⁺扩散区位于玻璃基片表面以下约10μm处, 形成光波导的芯部. 光波导芯部尺寸约为8μm×8μm, 与单模光纤芯径尺寸相当, 保证了较低的光纤耦合损耗. 对光波导的测量结果得出：在波长为1.5μm处条形光波导的传输损耗约为0.1dB/cm, 与单模光纤的耦合损耗约为0.2~0.3dB. 条形光波导的传输损耗与材料本身的损耗接近, 表现出掩埋式光波导的低损耗特征. 分析表明, 经过进一步优化, 这种光波导制备技术可用于低损耗光波导器件的制作.     

Low excess losses in a Y-branching plastic optical waveguide formed through injection molding

We have demonstrated low excess losses (1.9 dB at 660-nm wavelength) in a Y-branching plastic optical waveguide (POWG) that was fabricated using an injection-molding method. The waveguide had an amorphous vinyl polymer as the core and transparent polyolefin as the cladding. We then studied a method for isolating the excess loss in the Y-branching POWG, and with that method we estimated the lower limit of the loss to be 1.41 dB at 660 nm. The sample had a heat-resistant plastic optical fiber (POF) with a core composed of crosslinked poly (methyl methacrylate) (PMMA) copolymer, and a cladding composed of poly (tetrafluoroethylene-co-hexafluoropropylene). The POWG has sufficient reliability for ordinary uses below 100 °C. A model for a bidirectional wavelength-division multiplexing opticalcommunication system with the developed Y-branching POWG and the POF was also demonstrated.     

The diffusion of water in optical fibers

The diffusion of “water” (OH) into the core of optical fibers can affect the transmission properties. An increase in the water will result in an increased loss of high order modes, a reduction in numerical aperture, and increased microbending losses if there is coupling to these higher order modes. An extra 10ppm OH uniformly distributed through the core would produce 12dB/km loss at 0.95μm and about 1dB/km loss at 0.90μm.Based on the extrapolation of existing diffusion coefficient measurements and solubility data, calculations are made for the diffusion of atmospheric H₂O through the cladding into the core and also for the diffusion of OH from the cladding into the core. Diffusion can occur fairly rapidly during the high temperatures reached when depositing, collapsing, and drawing the fibers, and also slowly during extended period ambient temperature storage and use.     

High-bandwidth, graded-index polymer optical fiber for near-infrared use

We describe graded-index polymer optical fibers with high bandwidth (5.12 GHz for 100-m transmission) and low loss in the near-infrared region (56 and 115 dB/km at wavelengths of 688 and 773 nm, respectively) that we successfully obtained with a new interfacial-gel polymerization technique using an all-deuterated methyl methacrylate monomer and a partially fluorinated acrylate monomer. The necessity for both low attenuation and high bandwidth for a polymer optical fiber is described for its use as a physical media in a high-speed multimedia network.     

Water impurity in low-loss silica fibre

Water contamination in silica based optical fibre waveguides has been studied. The height of the 950nm water peak was found to vary with fibre pulling speed and reduced sharply from 64 dB/km to 20.5 dB/km as the speed was increased from 0.12 m/sec to 1.47 m/sec. The results have been fitted to a diffusion curve indicating that the water diffuses into the core region from the support tubes used in preform manufacture. Deposition inside a water free Spectrosil tube gave a water peak of only 4 dB/km. A B₂O₃ doped cladding layer was used to provide a barrier to OH migration and the 950nm water peak was reduced from 24 dB/km to 3 dB/km by increasing the B₂O₃ content in the layer from 2 to 4 mole per cent.     

Optical properties of GeO2 glass and optical fibers

The optical properties of GeO(2) glass were investigated to clarify its potentiality as an optical fiber material. Glass samples were prepared by the flame hydrolysis and the melting techniques, and their Rayleigh scattering and infrared absorption properties were examined. Optical fibers composed of a pure GeO(2) core and an F-doped GeO(2) cladding were drawn to clarify the scattering loss characteristics. The Rayleigh-scattering intensity obtained from spectral loss measurements on the fibers agreed with that measured in bulk samples, and the intensity relative to that of SiO(2) glass was found to be approximately 3. These results suggest that a minimum loss of 0.15 dB/km is expected at a wavelength of 2 mum.     

Long-range surface plasmon polariton waveguides embedded in fluorinated polymer

Low-attenuation waveguides based on the propagation of long-range surface plasmon polaritons (LRSPPs) along thin Au stripes embedded in low absorption perfluorocyclobutane (PFCB) polymer are presented. A new low in propagation loss of <2.0 dB/cm was achieved for a 4 microm wide waveguide by optimizing the cladding material and fabrication process. The coupling efficiency between the LRSPP waveguide and the optical fiber is studied theoretically and experimentally for different widths of Au stripes and various cladding thicknesses. Lower coupling loss is found when the cladding thickness is close to the mode diameter of the butt-coupled fiber. Based on the 2D distribution of SPP modes calculated by a finite-difference mode solver, a symmetric structure of multilayer claddings with different refractive indices is proposed to optimize device insertion loss.     

聚合物光纤用氟树脂材料性能特征

聚合物光纤POF用氟树脂材料首要的性能特征是具有低折射率、无定形、高透明特征,透光率以大于90%为佳,当氟树脂在POF中应用时要求同另一材料有匹配性要求:两者折射率相差0.03以上、膨胀系数及玻璃化温度相近;这种氟树脂不仅是优异的光纤皮材,而且是优异的光纤芯材.氟树脂用作POF芯材时,可降低POF的传输损耗,提高POF的耐温性、POF的传输带宽和POF的耐老化性能等,透明氟树脂是优异的POF芯皮材.     

High-purity As-S-Se and As-Se-Te glasses and optical fibers

We describe a procedure for the preparation of As-S-Se and As-Se-Te glasses with low contents of gas-forming impurities (hydrogen, oxygen, and carbon) via melting of extrapure-grade elements in an evacuated silica ampule and purification of the melt by chemical distillation. The impurity concentrations in the glasses thus prepared have been reduced to the following levels: hydrogen, <0.02; oxygen, 0.2; carbon, <0.02; silicon, <0.4 ppm by weight. Using the double-crucible method, we have fabricated glass fibers with various ratios of the core and cladding diameters (1: 25 to 9: 10), protected with a tetrafluoroethylene/1,1-difluoroethylene copolymer coating, which have an average bending strength of 0.5–1 GPa. The minimal optical losses are 150 dB/km at 6.6 μm in multimode As-Se-Te glass fibers and 60 dB/km at 4.8 μm in As-S-Se glass fibers. The effect of microinhomogeneities in the melt on the optical performance of arsenic sulfoselenide glass fibers fabricated by the double-crucible method is examined.     

Fabrication of matched cladding and depressed cladding single mode optical fibers

Abstract

Modified chemical vapor deposition method was used to fabricate single mode optical fibers. Both matched and depressed cladding single mode fibers were designed and fabricated. Loss as low as 0.3 dB/km has been obtained at wavelength 1.55 μm.     

Single-mode operation in few-mode optical fibre based on resonant coupling

The design of a low-bending loss few-mode optical fibre is proposed. Low-bending loss for the fundamental mode is achieved by increasing the index contrast between the core and the cladding, and a microstructured mode filtering region is applied to filter out the higher-order modes in the fibre. Numerical results show that the fundamental mode loss is lower than 0.03 dB/turn and the high-order mode is higher than 4.4 dB/turn at the bending radius of 5 mm and 1300–1600 nm wavelength range.