在空芯光纤研制方面，本项目分别制备了三种空芯光纤，分别是基于堆拉法拉制的空芯光纤，基于7孔反谐振型的PCF空芯光纤以及6孔单层负曲率PCF空芯光纤，最终拉制出反谐振型5腔空心光纤，从损耗曲线结果来看，光纤损耗2.2dB/km,覆盖C?波段到2μm波段，单模截止波长为1379.3nm,光纤包层直径为251.22um,非线性系数为0.0047W-1km-1,均满足目标考核指标。在高速空芯光纤传输方面，截取长度为500米的该空芯光纤，分别实现了100Gbit/s的PAM-4信号传输,120Gbit/s的PAM-4以及概率整形后的PS-PAM-6信号传输以及200Gbit/s的PS-256QAM高阶调制格式信号的传输。此时，空芯光纤传输系统的距离容量积达到100000Gbit/s*m。另外，我们采用空芯光纤实现了2微米新波段传输系统验证，实现了100Gbit/s的PS-DMT信号在100米空芯光纤中的传输。我们利用空心光纤(HCF)传输极化复用单载波QAM信号，总传输速率达到528 Gbit/s。我们首次通过实验实现了1.1 km长的 HCF在整个扩展C波段上的96通道的WDM相干传输，总传输容量达到50.7 Tbit/s,相继实现2km长度的HCF传输速率达到320Gb/s,达到新波段通信速率和距离指标要求。在集成匹配光源方面，匹配空心光纤的全波段宽带传输窗口，我们研制了覆盖C波段到2微米波段的匹配宽带光源，指标达到任务要求。In terms of the development of hollow fiber,this project has prepared three types of hollow fiber,namely hollow fiber drawn by the stacking method,PCF hollow fiber based on 7-hole anti resonant type,and 6-hole single-layer negative curvature PCF hollow fiber.Finally,an anti resonant 5-cavity hollow fiber was drawn.From the loss curve results,the fiber loss is 2.2 dB/km,covering the C-band to 2 μm.In the band,the single-mode cutoff wavelength is 1379.3nm,the fiber cladding diameter is 251.22um,and the nonlinear coefficient is 0.0047 W-1 km-1,all of which meet the target assessment indicators.In terms of high-speed hollow fiber transmission,the hollow fiber with a length of 500 meters was cut to achieve 100Gbit/s PAM-4 signal transmission,120Gbit/s PAM-4 signal transmission,PS-PAM-6 signal transmission after probability shaping,and 200Gbit/s PS-256QAM high-order modulation format signal transmission.At this point,the distance capacity product of the hollow fiber optic transmission system reaches 100000Gbit/s*m.In addition,we used hollow fiber to verify the 2-micron new band transmission system and achieved the transmission of 100Gbit/s PS-DMT signals in a 100 meter hollow fiber.We use hollow fiber(HCF)to transmit polarization multiplexed single carrier QAM signals,with a total transmission rate of 528 Gbit/s.For the first time,we have experimentally achieved 96 channel WDM coherent transmission of a 1.1 km long HCF over the entire extended C-band,with a total transmission capacity of 50.7 Tbit/s.We have successively achieved a 2-km long HCF transmission rate of 320Gb/s,meeting the requirements of new band communication rate and distance indicators.In terms of integrated matching light sources,we have developed a matching broadband light source that covers the C-band to 2-micron band,matching the full band broadband transmission window of hollow fiber,and the indicators meet the task requirements.

随着对网络带宽的需求越来越高，人们对光纤通信的容量也提出了更高的要求。现有的通信网络多采用单模光纤来实现长距离传输。然而，目前单模光纤的通信容量已经越来越接近其理论非线性香农极限。面对即将到来的光纤传输容量危机，科研人员致力于研究各种解决方案，例如新通信波段、新复用技术和新调制编码技术等，考虑到光信号的波长、偏振、时间等复用维度均已充分利用，新的可扩展复用维度必然将落在信号的空间维度上。利用模式作为新的复用维度的少模光纤传输技术被广泛认为是下一代光纤通信的主流趋势。本年度本项目以多维并行空分信道串扰理论为基础，对多芯少模光纤及其器件进行了设计、制备和测试，研发出7芯6模光纤、19芯3模光纤、超模光纤、低插损复用解复用器、少模光纤波长转换器、光交叉连接器等一系列成果，为高密度空分复用光纤的发展起到了积极的推动作用。As the demand for the bandwidth is greater,the requirement of the transmission of optical fiber is higher.Though single mode fiber is widely used in long-distance transmission nowadays,it still faces the crisis of capacity crunch.Thus new solutions such as new transmission wavelength,new multiplexing and new modulation and coding technology should be adopted.Considering the wavelength,polarization and timing already have been fully adopted,using mode as a new multiplexing dimension is widely considered as the main trend of the next generation optical fiber communication.Based on cross-talk theory of the multi-dimensional spatial channel allocation,design,manufacture and testing of multi-core few mode fiber have been performed and we obtained 7-core-6-mode fiber,19-core-3-mode fiber,coupled core fiber,low insert loss multiplexer and demultiplexer,wavelength converter of few mode fiber and so on,which has a positive effect on promoting the development of high density multi-dimensional space division multiplexing fiber.

在本项目执行期内，各单位围绕项目目标，依照项目任务书研究计划开展相关研究，各项研究任务已顺利完成，项目进度符合预期安排。目前取得的进展及主要成果包括:1、在新光纤方面。经过理论和工艺研究，已制备出低损耗7芯6模光纤、19芯3模光纤，以及8芯超模光纤，相关指标满足考核要求；对于模式复用/解复用器件，已制备出低损耗小体积的多芯光纤扇入扇出和模式复用/解复用光纤器件，并在实验验证系统中得到应用。2、在新放大方面。构建了光纤正/逆向多层光纤增益剖面设计方法和空分复用光纤模式增益竞争分析理论模型；制备了高浓度分层掺杂的空分复用掺铒光纤，铒离子掺杂浓度达到6200 ppm;设计并研制了泵浦耦合器件，基于空分复用掺铒光纤，搭建了增益均衡空分复用光纤放大器样机，增益倍数高于20 dB,增益差小于2 dB,达到考核指标要求；同时，对基于空分复用通信系统开展了传输距离和空分复用维数密度的实验验证研究，相应指标完成考核指标要求。3、在新波段方面。经过理论研究和工艺改进，制备出公里级的空心光纤，损耗满足项目指标要求；基于研制的空心光纤和宽带匹配光源，结合高阶调制技术，分别实现了C波段和2um波段的超100Gbit/s的信号传输，空心光纤通信系统的传输距离达到2km,并创造了传输容量达50.7Tbit/s的实验记录。目前，本项目发表SCI/EI科研论文110篇，申请发明专利61项，其中授权发明专利31项，撰写年度技术进展报告4份。总之，本项目研究内容实施进展顺利，各个单位紧密合作，互通有无，各项科研任务顺利完成。During the implementation period of this project,we focused on the project goals and carried out relevant research in accordance with the project research plan.The project progress is in line with the expected arrangements and all research tasks have been successfully completed.Firstly,in terms of new optical fiber research.After theoretical studies and fabrication improvement,low-loss 7-core 6-mode optical fiber,19-core 3-mode optical fiber,and 8-core supermode optical fiber have been fabricated,and the relevant key parameters meet the final goals of the project requirement;for the multiplexing/demultiplexing devices,low-loss multi-core optical fiber fan-in fan-out and mode multiplexer/demultiplexer with low insertion loss and small volume have been made and used in the experimental verification systems.Secondly,in terms of new amplification research.Constructed a forward/reverse multi-layer optical fiber gain profile design method and a spatial division multiplexing(SDM)fiber mode gain competition analysis theoretical model;prepared a erbium-doped optical fiber with high concentration layered doping,and the erbium ion doping concentration reached 6200 ppm;developed the pump coupling devices,built a gain-balanced SDM fiber amplifier prototype based on the fabricated active fiber,with the gain higher than 20 dB and a differential mode gain less than 2 dB;At the same time,experimental verification research on the transmission distance and SDM density has been carried out with the desired indicators.Thirdly,in terms of new wavelength-band research.After theoretical research and process improvement,the kilometer-level hollow-core fiber has been prepared,and the loss met the project index requirements;based on the developed hollow-core fiber and the broadband light source,combined with high-order modulation technology,>100Gbit/s of optical transmissions in the C-band and 2um band have been achieved respectively with the transmission distance up to 2km,and an experimental record of a transmission capacity of 50.7Tbit/s has been demonstrated.Currently,this project has published 110 SCI/EI papers,applied for 61 invention patents,including 31 authorized invention patents,and written 4 annual technology progress reports.In short,the implementation of the research content of this project has been implemented well,and various scientific research tasks are successfully completed under the closely cooperation with each other.

在本年度中，各单位围绕项目目标，依照项目任务书研究计划开展研究，各项任务正在有序进行当中，项目进度正常。目前取得的进展及主要成果包括: 在新光纤方面：对超模光纤和空心光纤的基本理论进行了初步研究;7芯6模光纤已有初步产品；设计制备了部分新型如高非线性少模光纤和保偏四模光纤；对于模式复用/解复用器件，已完成基本的理论建模和数值仿真，包括十模光子灯笼设计、全光纤型模式转换器和宽带低插损扇入扇出设备。 在新放大方面：对低模式增益差光纤的结构设计及增益均衡放大机理、新型有源光纤及放大机理、少模光纤放大器的增益均衡优化等已进行初步理论研究；建立了相干与非相干模型理论及其仿真，利用差拍效应与复包络初相位结合减小DMG;已通过试验验证稀土氯化物可在等离子体气相沉积的工艺平台上进行等离子体沉积，能够重复生产透明无气泡的预制棒。这些为后续新放大方面的研究工作打下了基础。同时，对基于少模光纤的模式复用通信系统开展了仿真研究，取得了一定结果。 在新波段方面：初步开展高阶调制技术，多维复用技术与概率整形编码技术的协调融合研究；提出了高阶调制技术、概率编码技术、多维复用技术与FEC编码技术相结合的大容量光通信光纤传输系统。 During the year,all the studies were around the project goals and in accordance with the project mission book research plan.All tasks were being carried out in an orderly manner and the project progress was normal.The current progress and main results include: In terms of new optical fibers:preliminary research on the basic theory of supermode optical fibers and hollow optical fibers;preliminary samples of 7-core 6-mode optical fibers have been prepared;and some new types such as highly nonlinear few-mode optical fibers and polarization-maintaining four-mode optical fibers have been prepared;The basic theoretical modeling and numerical simulation of mode multiplexing/demultiplexing devices have been studied,including ten-mode photon lantern design,all-fiber mode converter and broadband low insertion loss fan-in fan-out equipment. In terms of new amplification:preliminary theoretical research has been conducted on the structural design and gain equalization amplification mechanism of low modal gain difference fibers,new active optical fibers and amplification mechanisms,as well as gain equalization optimization of few-mode fiber amplifiers;The model and its simulation,using the beat effect and complex envelope phase to reduce differential mode gain(DMG).Meanwhile,it has been verified through experiments that rare earth chloride can be used for plasma deposition on a plasma vapor deposition process platform,and can repeatedly produce transparent and bubble-free preforms.These have laid the foundation for the subsequent research work on new amplification.At the same time,simulation research on mode multiplexing communication system based on few-mode fiber was carried out,and some results were obtained. In the new band:preliminary research on the coordination and integration of high-order modulation technology,multi-dimensional multiplexing technology and probability shaping coding technology;large-capacity combining high-order modulation technology,probability coding technology,multi-dimensional multiplexing technology and FEC coding technology is proposed Optical communication fiber transmission system. In short,the progress of the implementation of the annual tasks of the project is in good condition,and all scientific research tasks are carried out steadily.