A／D与D／A转换器技术

Ａ／Ｄ与Ｄ／Ａ转换器技术ＷＤ９４５１１１０位１００Ｍ采样／秒流水线子区ＢｉＣ－ＭＯＳＡＤＣ＝Ａ１０－ｂ１００－Ｍｓａｍｐｌｅ／ｓｐｉｐｅｌｉｎｅｄ　ｓｕｂ－ｒａｎｇｉｎｇＢｉＣＭＯＳＡＤＣ［刊，英］／Ｓｏｎｅ，Ｋ．…／／ＩＥＥＥＪ．Ｓｏｌｉｄ－Ｓｔａ...     

4×622Mb／sWDM40km光通信系统实验

本文完成了我国第一个４×６２２Ｍｂ／ｓ波分复用（ＷＤＭ）光通信系统实验，使单根光纤线路通信容量达２．４Ｇｂ／ｓ。该系统以ＤＦＢ－ＬＤ为光源，工作波长在１．５５μｍ附近，ＬＤ的工作频率稳定度优于±１５０ＭＨｚ，信道间隔２ｎｍ左右，无中继传输距离为４３．６ｋｍ，采用Ｆ－Ｐ调谐光滤波器作为解复用器，接收机灵敏度达－３０ｄＢｍ。     

HDSL E1／T1传输系统

ＨＤＳＬ　Ｅ１／Ｔ１传输系统一种高速数字用户线传输系统，其中包括本端、远端传输单元和相关维护接口单元。可无中继地沿一般铜绞合线对传输Ｅ１（２．０４８Ｍｂ／ｓ）或Ｔ１（１．５４４Ｍｂ／ｓ）业务分别达４．６公里（Ｅ１）或５．６公里（Ｔ１），无需拆解桥接抽...     

一种新的用于高速波分复用系统的色散补偿方案

本文提出了一种用于高速多路波分复用（ＷＤＭ）陆上级联掺铒光纤放大器（ＥＤＦＡ）光纤通信系统的色散补偿方案，其特点是：利用特殊设计的色散位移光纤ＳＤＤＳＦ（零色散波长λ０≈１．６μｍ，色散斜率Ｓ＿０＝０．０５ｐｓ／ｋｍ／ｎｍ２），在１５５０ｎｍ处产生－２～－４ｐｓ／ｋｍ／ｎｍ的色散，以避免ＩＴＵ－ＴＧ．６５３色散位移光纤在多路复用时的四波混频（ＦＷＭ）效应；并利用ＩＴＵ－ＴＧ．６５２标准单模光纤（非色散位移光纤ＮＤＳＦ）在１５３０～１５７０ｎｍ（ＥＤＦＡ工作带宽）范围内，有效地补偿ＳＤＤＳＦ所引入的负色散。此方案可使单路数据率高于１０Ｇｂ／ｓ的波分复用系统，经１０００ｋｍ传输后因色散引入的眼图恶化量仍＜１ｄＢ。     

2．4Gb／s高频率稳定度光发送机研制

本文研制出调频响应达１．３ＧＨｚ的ＬＤ模块，并根据ＷＤＭ系统传输实验的需要，研制出频率稳定度优于上１５０ＭＨｚ的２．４Ｇｂ／ｓ光发送机。该发送机现已成功地用于２．４Ｇｂ／ｓ光通信系统的传输实验中。     

波分复用传输系统中EDFA-BDE模块的仿真研究

本文在ＣＯＭＤＩＳＣＯ信号处理工作系统中研究了用于波分复用传输系统的掺铒光纤放大器块图编辑器仿真模块。仿真模块考虑了前向及后向放大的自发辐射噪声。通过信息计算ＥＤＦＡ－ＢＤＥ模块,优化设计了掺铒光纤的长度。在含８级ＥＤＦＡ的ＷＤＭ光传输系统的仿真中论证了模块的实际应用。本文在输出信号幅度及ＡＳＥ噪声谱上都获得了与前期发表的实验相一致的仿真结果,证明了ＥＤＦＡ－ＢＤＥ模块在高饱和状态下的实际可用性。     

TN64 10 Gbit／s传输平台与多波长光放大器

北电网络是第一个向市场提供１０Ｇｂｉｔ／ｓＳＯＮＥＴ／ＳＤＨ产品并通过单纤双向密集波分复在一根光纤上传输的供应商边套系统与已敷设的光纤完全兼容。目前,１０Ｇｂｉｔ／ｓＳ／ＤＭＳ传输系统系统与ＤＷＤＭ结合在一起,能够提供３２０Ｇｂｉｔ／ｓ的容量。     

AlGaAs／InGaAs功率PHEMT用异质材料的计算机优化与器件实验结果

借助一新的工艺模拟与异质器件模型用ＣＡＤ软件──ＰＯＳＥＳ（Ｐｏｉｓｓｏｎ－ＳｃｈｒｏｅｄｉｎｇｅｒＥｑｕａｔｉｏｎＳｏｌｖｅｒ），对以ＡｌＧａＡｓ／ＩｎＧａＡｓ异质结为基础的多种功率ＰＨＥＭＴ异质层结构系统（传统、单层与双层平面掺杂）进行了模拟与比较，确定出优化的双平面掺杂ＡｌＧａＡｓ／ＩｎＧａＡｓ功率ＰＨＥＭＴ异质结构参数，并结合器件几何结构参数的设定进行器件直流与微波特性的计算，用于指导材料生长与器件制造。采用常规的ＨＥＭＴ工艺进行ＡｌＧａＡｓ／ＩｎＧａＡｓ功率ＰＨＥＭＴ的实验研制。对栅长０．８μｍ、总栅宽１．６ｍｍ单胞器件的初步测试结果为：ＩＤｓｓ２５０～４５０ｍＡ／ｍｍ；ｇｍ０２５０～３２０ｍＳ／ｍｍ；Ｖｐ－２．０－２．５Ｖ；ＢＶＤＳ５～１２Ｖ。７ＧＨｚ下可获得最大１．６２Ｗ（功率密度１．０Ｗ／ｍｍ）的功率输出；最大功率附加效率（ＰＡＥ）达４７％。     

LMDS在宽带无线接入建设中的应用

ＬＭＤＳ系统的应用 ＬＭＤＳ工作在１０～３８ＧＨｚ的毫米波的波段内,可用的带宽达到１ＧＨｚ以上,最大数据分配带宽为４．８Ｇｂ／ｓ,比ＭＭＤＳ（２００ＭＨｚ）和ＤＢＳ（８００ＭＨｚ）宽得多。ＬＭＤＳ几乎可以提供任何种类的业务,支持话音、数据和图像业务,并支持ＡＴＭ、ＴＣＰ／ＩＰ和ＭＰＥＧ ２等标准。目前ＬＭＤＳ主要应用在以下几个方面： １．高质量的话音业务：通过ＣＥＳＥ１电路为ＰＡＢＸ提供数字中继线的连接,还可用于移动通信一点对多点的基站互联。 ２．高速数据业务：通过１０ＢＡＳＥ－Ｔ和１００ＢＡＳＥ－…     

高清晰度电视中8—VSB与COFDM传输方案的分析比较

本文简要介绍高清晰度电视中８－ＶＳＢ和ＣＯＦＤＭ传输方案及其基本原理，并针对传信率为１／Ｔ＝２３．５４８Ｍｂｐｓ的８－ＶＳＢ生ＣＯＦＤＭ作了计算机模拟，最后对该两种传输系统作了结构和性能上的比较分析。     

Performance of eight-channel OEIC p-i-n/HBT receiver array in8×2.5 Gb/s WDM transmission system

The performance of an eight-channel, 2.5 Gb/s OEIC photoreceiver array in an eight-wavelength long-distance WDM testbed is described. The sensitivity penalties due to crosstalk and transmission are measured, and the source of crosstalk is investigated. Channel sensitivities range from -25.4 to -26.2 dBm after transmission through 720 km of standard fiber, with transmission penalties ranging from 0.3 dB to 1.0 dB. When the power in each of seven interfering channels is 5 dB above sensitivity, the maximum crosstalk penalty suffered by an individual channel does not exceed 1 dB. These experiments are the first comprehensive characterization of monolithic receiver arrays for crosstalk performance under multichannel operation in a realistic system environment     

Uni- and bidirectional 4λ×560 Mb/s transmissionsystems using WDM devices based on wavelength-selective fusedsingle-mode fiber couplers

Four-wavelength-channel wavelength-division multiplexing (WDM) lab transmission system experiments with buried heterostructure (BH) lasers at 1200-, 1240-, 1280-, and 1320-nm wavelengths, all-fiber WDM devices, and 20-km single-mode link fiber at a 560-Mb/s bit rate demonstrated that unidirectional and bidirectional WDM transmission systems could be operated successfully by using all-fiber 4λ multiplexing, 4λ demultiplexing, or 4λ multiplexing/demultiplexing devices with a low insertion loss per wavelength channel (2.1-4.7 dB), enough optical far-end crosstalk attenuation (18-37 dB), and high optical near-end crosstalk attenuation (43-49 dB). It is concluded that the four-wavelength-channel WDM lab transmission system at 560 Mb/s mainly used as a test bed is not representative of future unidirectional trunk WDM systems. Such systems favor distributed feedback (DFB) lasers in the 1500-1560-nm wavelength range where fiber attenuation is lower than in the 1200-1320 nm wavelength range and where 1500-nm DFB lasers with a smaller linewidth do not limit the repeater distance as much because of mode partition noise     

Dynamic power-equalized EDFA module based on strain tunable fiberBragg gratings

An adaptive power-equalized erbium-doped fiber amplifier (EDFA) module is proposed and experimentally demonstrated by using strain tunable fiber Bragg gratings (FBGs). In a demonstration for a five-channel wavelength-division-multiplexed (WDM) system, the EDFA module can effectively reduce the power variation from 11 dB to 0.3 dB. Measured power penalty for 2.5-Gb/s data is less than 0.5 and 1.1 dB for 5 and 17 dB of signal attenuation by tunable FBGs, respectively. The power-equalized EDFA module can find wide applications in WDM lightwave transmission systems     

Gain-flattened Er/sup 3+/-doped fiber amplifier for a WDM signal in the 1.57-1.60-/spl mu/m wavelength region

A gain-flattened Er/sup 3+/-doped silica-based fiber amplifier (EDFA) has been constructed for a 1.58-/spl mu/m band WDM signal. This EDFA exhibits uniform amplification characteristics with a gain excursion of 0.9 dB for a four-channel WDM signal in the 1.57-1.60 /spl mu/m wavelength region. The average signal gain and the noise figure for the WDM signal are 29.5 dB and less than 6.3 dB, respectively. The use of this EDFA in parallel with a 1.55-/spl mu/m band EDFA will expand the WDM transmission wavelength region.     

Polarization independent InP WDM multiplexer/demultiplexer module

We report the design, fabrication, packaging, and characterization of a polarization independent integrated optical InP multiplexer/demultiplexer module. The device is based on a vertically etched diffractive grating and separates four channels with 4 spacing in the 1.55 μm window. An n^-/n⁺-InP layer structure with very low birefringence results in a shift of the passbands between transverse electric (TE) and transverse magnetic (TM) polarization of less than 0.1 nm. With a self-aligned flip-chip mounting technique light is optically coupled from the input and output waveguides to an array of lensed single mode fibers with a coupling efficiency of more than 80%. The packaging includes temperature control that allows fine tuning of the channel passbands over 5 nm. Optical crosstalk is always better than -17 dB and fiber to fiber losses of 15 dB are achieved. The module has been successfully implemented in a 4×2.5 Gb/s WDM transmission system     

光纤光栅和环行器构成的多路光分插复用器

讨论由光纤光栅和光环行器构成的光分插复用器的结构,性能和特点,提出采用一段刻有多个光纤布拉格光栅的光纤,两个光环行器,WDM复用器和解复用器等器件,构造能够对WDM的多个信道实施分插操作的光分插复用器,该光分插复用器的插入损耗要比简单地把多个单路的光分插复用器进行级联时小得多,波分复用全光网络中的光分插复用技术,是实现波分复用网络的关键技术之一。     

Simultaneous all-optical frequency downconversion technique utilizing an SOA-MZI for WDM radio over fiber (RoF) applications

Simultaneous all-optical frequency-downconversion technique utilizing a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) is experimentally demonstrated, and its application to a wavelength-division-multiplexing (WDM) radio over fiber (RoF) uplink is proposed. The conversion efficiencies from 22.5 (f/sub RF/) to 2.5 GHz (f/sub IF/=f/sub RF/-2f/sub LO/) are in the range from 1.5 to 3 dB for the optical RF wavelength between 1548 and 1558 nm. Error-free simultaneous all-optical frequency downconversion of the two WDM RoF upstream channels that carry 155-Mb/s differential phase-shift keying data at 22.5 GHz to an optical intermediate frequency signal having the frequency of 2.5 GHz with the power penalty less than 0.1 dB at the bit error rate of 10/sup -8/ is achieved.     

Eight-channel p-i-n/HBT monolithic receiver array at 2.5 Gb/s perchannel for WDM applications

We report a monolithic chip incorporating an eight channel p-i-n/HBT photoreceiver array designed for multichannel WDM applications. The p-i-n photodetectors are edge illuminated and centered at a 250 μm pitch for mating with either ribbon fiber connectors or waveguide demultiplexers. Each channel operates at 2.5 Gb/s with an electrical crosstalk of -20 dB between adjacent channels. The average sensitivity of each receiver in the array was measured to be (-20±1) dBm for a bit error rate of 10^-9 at a wavelength of 1.5 μm     

980/1 550保偏光纤波分复用器

从耦合模理论出发,分析了980／1550熔融拉锥（FBT）型保偏光纤（PMF）波分复用器（WDM）的工作原理,设计了WDM的制作方法。在FBT台上,通过控制火焰的温度和宽度以及拉伸速度,有效控制WDM的拉伸长度和耦合区结构,用1550nm的PMF和H11060单模光纤（SMF）成功研制了高性能的980／1550PMFWDM。测试结果表明：在1550nm波长上,该WDM具有0．2dB的插入损耗、32dB的隔离度和22．8dB的消光比偏振特性;在980nm波长上,具有0．2dB的插入损耗、14_8dB的隔离度。该器件除了具有SMFWDM的特性外,1550nm端口还具有偏振保持特性,它将促进PMF激光器和放大器快速发展。     

Fluoride-based erbium-doped fiber amplifier with inherently flat gain spectrum

We successfully developed a fluoride-based Er/sup 3+/-doped fiber amplifier (F-EDFA). An average signal gain of 26 dB was achieved for 8 channel wavelength division multiplexed (WDM) signals in the 1532-1560 nm wavelength region with a gain excursion of less than 1.5 dB at an input signal power of -20 dBm per channel. Furthermore, we studied the amplification characteristics of the F-EDFA for WDM signals. The following experimental results were obtained. (1) For an 8-channel WDM signal in the 1532 to 1560 nm wavelength region, the gain excursion between channels can be suppressed to within 1.5 dB. However, the wavelength region allowing a gain excursion of 1.5 dB, is between 1536-1560 nm for the silica-based Er/sup 3+/-doped fiber amplifier. (2) F-EDFAs have a flat gain region between 1534-1542 nm. The gain excursion of this region is less than 0.2 dB for WDM signals.