光通信用光纤端面截止滤光膜的研制

为了满足光通信中对光纤端面镀多层膜的特殊需求,分析了光纤端面镀制截止滤光膜所存在的难点问题,利用TFCalc薄膜设计软件,采用解析法设计了一个初始膜系,再结合梯度优化法对初始膜系进行优化处理,成功设计出具有较好光谱性能的光纤端面截止滤光膜的膜系,并对德国莱宝APS1104型镀膜机进行了内部结构和镀制工艺的改进,最终采用离子源辅助沉积进行低温镀制,获得了性能优良的光纤端面截止滤光膜。结果表明,在光纤端面镀制多层的截止滤光膜,虽然存在很多困难,但选择合适的膜系和镀制工艺,依然能获得符合实际要求的滤光膜。     

光纤到户单纤三向截止滤光片的研制

单纤三向技术是无源光接入网实现音频、视频、数据集成传输的关键技术.用光学薄膜实现无源光网络的波分复用要求部分滤光片的入射角为45°,大角度入射会造成s偏振光和p偏振光分离,为了减少信道间的干扰,要求滤光片在45°入射的情况下,同时具有低插入损耗和高通带隔离度,按照常规膜系设计方法及镀制工艺,很难镀制成功.采用解析法和自动优化法综合设计了45°入射单纤三向干涉截止滤光片,分析了膜厚改变2％对设计膜系透过率曲线及参数的影响,采用德国莱宝APS1104型镀膜机,针对所设计的非规整膜系选择合适的镀制工艺进行实际镀制,获得了性能优良的大角度入射单纤三向截止滤光片.     

1.3～2.7 μm带通滤光膜研制与分析

光学薄膜技术广泛应用于几乎所有的光学系统、光电系统和光电仪器。新型探测器的发展对1～3 μm近红外波段附近的能量响应提出了滤波的要求。从电磁场理论和麦克斯韦方程出发,介绍了光学薄膜的设计理论,论述了带通滤光膜的设计方法。基于Optilayer软件,以氧化铝为基底,设计了一种工作波段为1.3～2.7 μm的近红外带通滤光膜。考虑到镀膜材料的匹配性问题,选择硫化锌和氟化镱作为高、低折射率材料。采用长波通与短波通相结合的设计方法,并用Optilayer软件完成了膜系的计算和优化。在氧化铝基底双面镀制膜,用电子束蒸发和离子束辅助沉积的制备工艺完成了膜系镀制。用分光光度计对制备样品进行了透过率测试。结果表明,在1.3～2.7 μm设计波段,样品的平均透过率大于95%,符合带通滤光膜的设计要求。     

多层膜镀制过程中监控片的最优化更换策略

研究了分离法监控多层膜淀积时监控片的更换策略问题。分析了不同的监控片更换策略对所淀积薄膜光学特性的影响,得出了监控片的更换策略也是决定所镀制光学薄膜成功与否的关键因素之一的结论。提出了利用最优化原理和计算机模拟薄膜淀积来确定多层膜镀制过程中监控片的最优化更换策略的新方法,并设计了相关的计算机程序。在基于反射率极值法监控的镀膜机上进行的实验结果表明：用设计的程序可得到一定工艺条件下镀制多层规整膜系时应采取的监控片更换策略。这对于多层膜的实际镀制具有指导意义。     

激光雷达测距系统中滤光片的制备

针对激光雷达测距系统的使用要求,通过对镀膜材料的光学特性、膜系设计和监控方法的分析,优化工艺参数,采用电子束真空镀膜的方法,同时加离子辅助系统,选用TiO2和SiO2氧化物硬质薄膜材料在HB830颜色玻璃基底上镀制窄带滤光膜.用maclod灵敏度算法分析膜层的相对灵敏度,减小厚度监控误差,改进制备工艺过程,寻求膜系的最佳控制方法.所镀膜层在垂直入射的条件下,905 nm波长的透过率达86%以上,半峰值宽度为23 nm,并且通过提高膜厚控制精度解决了中心波长漂移、膜层吸收等问题.该膜层能够承受激光光源的照射,抵御恶劣的使用环境.     

宽波段7:3 消偏振分光膜的设计及镀制

分光膜在倾斜使用时会存在较强的偏振效应,通常采用各种措施来减小这种偏振效应的影响,但基本上只能在单一波长或较窄波段范围内实现消偏振分光,其波段范围几乎不超过50 nm。根据设计要求运用解析法设计出一个合适的初始膜系,再在所设计的初始膜系基础上,运用TFCalc膜系设计软件采用解析法、Needle和变尺度优化法综合设计了45入射1 260～1 360 nm波段7:3消偏振分光膜,分析了该设计膜系的监控曲线以评价其可镀制性,并采用德国莱宝APS1104型镀膜机对所设计的膜系进行了实际镀制,获得了性能优良的45入射宽波段7:3消偏振分光膜。     

红外探测器滤光膜的研究与制备

为满足红外探测器在1.064 m和3~5 m双波段透射,在1.2~2.8 m波段反射,可适应复杂的环境条件、具有高稳定性和可靠性等要求,依据薄膜的设计理论,选择合理的膜系设计方法,借助TFC膜系设计软件对膜系结构进行优化设计。并采用电子束真空蒸发和离子辅助沉积技术,在蓝宝石晶体基底上镀制红外多波段滤光膜。同时对所使用的薄膜材料的光学、物理、化学和机械特性进行分析与研究。通过反复试验,优化工艺参数,使多波段滤光膜得以实现。对所制得的薄膜进行测试,基本满足红外探测器的使用要求。     

Ge基底8～11.5μm长波通滤光膜的研制

论述了在Ge基底上镀制8～11.5 μm红外长波通滤光膜.通过对Ge基底和Ge、ZnS膜料的色散计算,优化膜系设计,进行工艺实验以及膜层的光学及耐环境实验,制备出满足应用条件的红外长波通滤光片,并已批量生产.     

3.7～4.8μm中红外带通滤光膜研制

以光学薄膜理论为出发点,系统介绍了3.7～4.8 m带通滤光膜的理论设计与优化、实际生产制备以及成品测试方法。考虑到膜料性能及膜层匹配等问题,分别选用锗和一氧化硅作为高低折射率材料,并以氧化铝作为薄膜基底。确定了滤光膜的基础膜系,并使用Filmaster软件对膜系进行了设计和优化计算。在薄膜蒸镀过程中,根据材料选取合适的镀制工艺。通过温度控制、离子辅助等方法研制出了可靠性与光谱特性皆优的带通滤光膜,并对其光谱特性及膜层质量等进行了测试。根据设计目标修改工艺参数,最终确定可行的工艺流程,从而研制出了符合光学性能设计指标的3.7～4.8 m带通滤光膜。     

1064 nm激光平板偏振膜的研制

根据军用光学仪器的使用要求,在平板K9基底上镀制偏振膜,要求在56.4°角入射条件下,激光波长1064 nm处满足T_P>99%,T_S<1%,且膜层抗激光损伤阈值应≥600 MW/cm~2.采用电子束真空镀膜的方法并加以离子辅助沉积系统,通过选择HfO_2和SiO_2作为高低折射率材料,利用Macleod软件进行膜系设计与分析,采用LightRatioPeak光值比例法进行监控,优化工艺参数,减少监控误差,在平板K9基底上成功镀制符合使用要求的偏振膜.所镀膜层不仅满足光谱要求,且顺利通过膜层环境测试,完全满足军用光学仪器的使用要求.     

波分多路系统的光辉前程

本文首先简述频分,时分和波分多路伟输系统的发展过程,详细释波争多路所需的光纤和小分多路合用的光纤放大器。然后,说明波分多路系统在传输干线和在全光通信网应用的光辉前景。     

A Simple One-System Solution COF-PON for Metro/Access Networks

In this paper, next-generation ultralong reach code division multiplexing (CDM) on fiber (COF) passive optical network (COF-PON) based on CDM (multiplexing carried out in electrical domain) presented here. We describe the system configuration, COF transceiver, key merits such as bidirectional transmission (on the same wavelength with single fiber), extending the reach by coding gain, and offering huge bandwidth to large number of subscribers by overlaying on coarse wavelength division multiplexing (CWDM)/wavelength division multiplexing (WDM). We believe our newly proposed ultralong reach COF-PON will help to drastically reduce the Capex and Opex costs by consolidating metro and access networks into one simple network. We demonstrated initial experimental results over 100-km bidirectional COF-PON overlay on 4lambda-CWDM channels' transmission without the use of an optical amplifier     

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.     

光网络技术的发展与应用

主要从TDM（时分复用）、WDM（波分复用）、光纤技术、节点技术及全光网络等方面的发展介绍了近阶段光网络技术的发展与应用。     

基于相干光正交频分复用的WDM传输系统及其性能分析

相干光正交频分复用由于其良好的传输性能成为近年来光传输领域的研究热点,波分复用技术可以在光纤中通过增加并行波长的数量来提高系统的容量,将CO-OFDM和WDM技术结合,可以构造出高速率、大容量、低成本的光传输网络。文章首先对基于CO-OFDM的WDM传输系统的理论模型和基本原理进行了研究,然后对基于CO-OFDM的100Gb/s×32-信道WDM传输系统进行了仿真分析。并研究了该系统的传输性能。结果表明：在没有任何光纤的色散及非线性补偿的情况下,当信号速率为3.2 Tb/s时,系统的Q因子高于16.0 dB,在标准单模光纤中的传输距离可达1500km。     

射频反馈法实现声光可调谐滤波器稳频输出

在集成声光可调谐滤波器(AOTF)工作时,由于环境温度变化以及自身声表面波吸收使器件的温度发生变化,导致滤出波的中心波长发生漂移。在理论分析的基础上,对声光可调谐滤波器的温度特性进行了实验研究,并在此基础上提出一种新的解决方案:用动态控制射频信号来实现声光可调谐滤波器的稳频输出,并用该方案实现了中心波长的漂移控制在0.08 nm以内,满足了波分复用(WDM)通信系统的应用要求。     

622-Mb/s Bidirectional SFP Optical Transceiver Using an Integrated WDM Optical Subassembly

The 1.3/1.55-mum bidirectional small form pluggable (SFP) optical transceiver with an integrated wavelength division multiplexing (WDM) subassembly using accurate ceramic blocks has been developed. The WDM subassembly on which a laser diode, a receiver photodiode, a WDM filter, and two microlenses are integrated is only 2.0 times 2.1 times 0.6 mm³ in size and inserted in a TO-CAN package. The SFP transceiver coupled with single-mode fiber has been operated at a 622-Mb/s data rate. The transmitted optical output power is -2.8 dBm and the measured value of sensitivity is -32 dBm at 10^-10 bit-error rate.     

基于WDM和TDM的串联FBG高速列车定位系统

介绍了一种基于波分复用（WDM）和时分复用（TDM）串联光纤Bragg光栅（FBG）的高速列车定位系统。用快速的光功率监测替代FBG的波长监测,定位时延较小（0．2s）;波长漂移转化为光功率的一对负正脉冲波动,提高了定位自动识别的准确性;同时WDM与TDM相结合的系统结构设计,扩大了列车定位系统监测的总长度。     

Choice of MUX/DEMUX filter characteristics for NRZ, RZ, and CSRZ DWDM systems

This paper investigates the influence of filter bandwidth and flank steepness of both multiplexing and demultiplexing filters in dense wavelength division multiplexed systems (spectral efficiency 0.8 b/s/Hz) in the presence of coherent wavelength division multiplexing (WDM) crosstalk. Using a recently introduced technique for the statistically reliable performance prediction of systems impaired by coherent WDM crosstalk, this paper presents numerical results for nonreturn-to-zero (NRZ), 33% duty-cycle return-to-zero (RZ), and 67% duty-cycle carrier-suppressed return-to-zero signals. This paper confirms that steep filter flanks are generally preferable, both in terms of optical signal-to-noise ratio penalty and in terms of filter bandwidth tolerance.