MMI型1.31/1.55 μm GaAs波分复用/解复用器的研制

利用多模波导的自镜像原理,分析设计了一种能直接与单模光纤相耦合的具有最小循环比的1.31/1.55 μm波长的GaAs/GaAlAs波分复用/解复用器。该器件的输入、输出单模波导和SIE多模波导采用离散谱折射率法进行优化设计,最后获得了当输入、输出单模波导宽为3 μm、SIE多模波导宽度和最佳耦合长度分别为18 μm和5 602.8 μm时,该器件对1.31 μm和1.55 μm两个波长的隔离度均在70 dB以上,且传输损耗小于0.1 dB。     

A 4 Gbits/s GaAs 16:1 multiplexer/1:16 demultiplexer LSI chip

A GaAs 16:1 multiplexer (MUX)/1:16 demultiplexer (DMUX) LSI chip, which operates at data rates from 50 Mb/s up to 4 Gb/s in a multilayer ceramic package, is described. The LSI chip incorporates trees of 2:1 MUX and 1:2 DMUX. The 2:1 MUX is composed of a master-slave D-flip-flop (DFF) joined with a 2-1 selector. The 1:2 DMUX consists of DFFs which are either a master-slave or the tristage type. The package has 76 pins and consists of five layers, including four power layers, and is applicable up to 7.7 GHz operation. The LSI chip is fabricated using a flat-gate self-aligned implantation for n⁺-layer technology (FG-SAINT process)     

26GS/s单bit量化降速芯片

基于1μm GaAs HBT工艺设计并实现了一种26GS/s单bit量化降速芯片。芯片采用树形级联架构,集成前端宽带比较器,综合优化各级降速单元拓扑,在功耗、速度各方面达到最优化。测试结果表明,芯片在26GS/s转换速率下,其SFDR大于8dBc,数据带宽达13GHz,显示出其在电子对抗及高速数据处理方面的潜力。     

基于FPGA的高速DMUX设计

介绍了基于Altera公司FPGA的高速DMUX(数据分路器)设计.通过与DMUX专用器件的比较,说明了这种实现方式的优势.     

Ultrahigh-speed heterojunction bipolar transistormultiplexer/demultiplexer ICs

High-speed 2-b monolithic integrated multiplexer (MUX) and demultiplexer (DMUX) circuits have been developed using self-aligned AlGaAs/GaAs heterojunction bipolar transistors (HBTs) with improved high-speed performance. Both ICs were designed using emitter-coupled logic. The 2:1 MUX was composed of a D-type flip-flop (D-FF) merging a selector gate and a T-type flip-flop (T-FF). The 1:2 DMUX consisted of two D-FFs driven at a clock of half the rate of the input data. Error-free operation with a pseudorandom pattern was confirmed up to 10 Gb/s. The rise and fall times of the output signals of both ICs were 40 and 25 ps, respectively. HBT frequency dividers were used as inputs for both ICs in order to find the maximum operation speed. Although only a few test patterns were available, the maximum operation speeds of the MUX and DMUX were found to be around 15 and 19 Gb/s, respectively     

基于空时分组编码的协同通信系统性能的研究

该文提出了一种基于空时分组编码的协同通信方案(WCC-STBC),通过理论分析得到了系统的误码率传输特性,并给出了Monte Carlo仿真结果。理论分析和仿真结果表明:WCC-STBC方案通过临近用户之间的空时协同发送可获得分集增益,增益的大小与协同信道及各用户信道的传输特性有关。在误比特率为10-3,两用户间协同信道的传输特性优于各用户(假设各用户传输特性相同)5dB时可获得约3dB的分集增益;一个用户信道的传输特性(假设其与两用户间协同信道传输特性相同)优于另一用户5dB时,信道传输特性较差的用户可获得约5dB的性能提升,且较好信道用户的性能损失并不大,仅约0.5dB。     

Two-Stage Channel Estimation Algorithm for TD-SCDMA System Employing Multi-Cell Joint Detection

The conventional Steiner channel estimator is inefficient for TD-SCDMA systems employing multi-cell joint detection because of its low estimation accuracy. A novel two-stage channel estimation algorithm was presented by re-defining the channel estimation matrix to mitigate the noise in the channel estimation. It is based on matched filter and minimum mean square error channel estimation results and it refines the initial channel estimation using inter-symbol interference and multiple access interference elimination. Simulation results prove the validity of the proposed algorithm for estimation accuracy upgrade, contributing to 10.2 dB and 6.8 dB BER performance improvement for the outdoor-to-indoor A channel and Vehicular A channel respectively.     

基于硅纳米线波导的16通道200GHz阵列波导光栅

设计了基于硅纳米线波导的16通道,通道间隔为200GHz的阵列波导光栅(AWG)。传输函数法模拟了器件传输谱,结果表明器件的通道间隔为1.6nm,通道间串扰为31dB。器件利用SOI材料,由193nm深紫外光刻工艺制备。光谱测试结果分析表明,通道串扰为5-8dB,中心通道损耗2.2dB,自由光谱区长度24.7nm,平均信道间隔1.475nm。详细分析了器件谱线畸变的原因。     

Technique for widening passband of wavelength router

A new method to broaden the passband of arrayed-waveguide grating routers is proposed. A sinc(x) intensity distribution is formed in the array by a slot etched in the input star coupler. A 3 dB bandwidth of 65 GHz is obtained for a 100 GHz channel spacing and the adjacent channel crosstalk is less than 25 dB.     

16 channel 200 GHz arrayed waveguide grating based on Si nanowire waveguides

A 16 channel arrayed waveguide grating demultiplexer with 200 GHz channel spacing based on Si nanowire waveguides is designed.The transmission spectra response simulated by transmission function method shows that the device has channel spacing of 1.6 nm and crosstalk of 31 dB.The device is fabricated by 193 nm deep UV lithography in silicon-on-substrate.The demultiplexing characteristics are observed with crosstalk of 5-8 dB,central channel’s insertion loss of 2.2 dB,free spectral range of 24.7 nm and average channel spacing of 1.475 nm.The cause of the spectral distortion is analyzed specifically.     

Wavelength multiplexer based onSiO2-Ta2O5 arrayed-waveguide grating

The characteristics of a wavelength multiplexer based on an arrayed-waveguide grating are carefully investigated by using the grating theory and related experiments. A 28-channel multiplexer is designed and fabricated as SiO₂-Ta₂O₅ waveguides on a 1 cm×2 cm substrate. The designed wavelength channel spacing of 1 nm is obtained. The crosstalk to an adjacent channel is -15 dB. The measured minimum loss is 4.2 dB, which is composed of 3.4 dB excess loss and 0.8 dB grating loss     

16-channel surface-acoustic-wave grating-filter bank for real-time spectral analyser

A 16-channel surface-acoustic-wave grating-filter bank has been constructed on four y-cut LiNbO3 crystals. Each channel has a 4dB bandwidth of 6.7 MHz. The insertion loss at the peak of the passband of each channel is ?32 dB, ±1.2 dB. The centre frequencies are 6.7 MHz apart and span the range 150?250 MHz. This filter has been incorporated in a realtime spectral analyser.     

High-speed 8:1 multiplexer and 1:8 demultiplexer implemented withAlGaAs/GaAs HBTs

An 8:1 multiplexer (MUX) and 1:8 demultiplexer (DMUX) implemented with AlGaAs/GaAs heterojunction bipolar transistors are described. The circuits were designed for lightwave communications, and were demonstrated to operate at data rates above 6 Gb/s. These are among the fastest 8-b MUX-DMUX circuits ever reported. Each contains about 600 transistors and consumes about 1.5 W. The pair provides features such as resettable timing, data framing, and clock recovery circuitry, and a built-in decision circuit on the DMUX. Emitter-coupled logic (ECL) compatible input/output (1/O) signals are available. The circuits were implemented with bi-level current mode logic (CML) and require a -5.2-V power supply and a +1-V bias for ECL compatibility     

旋转星座下匙孔信道的四元素准正交空时分组码研究

提出了一种基于匙孔信道的旋转四元素准正交空时分组码(QQOSTBC-CR,Constellation Rotation Quaternion Quasi-Orthogonal Space Time Block Code),该码可以通过极化天线进行发射和接收,设计出发射天线数为8的QOSTPBC-CR,并对N＝8的情况进行成对译码,最后与匙孔信道下传统旋转准正交空时分组码(QOSTBC CR,Constellation Rotation Quasi Orthogonal Space Time Block Code)、准正交空时分组码(QOSTBC,Quasi Orthogonal Space Time Block Code)以及瑞利信道下QQOSTBC-CR进行了仿真比较.结果表明:对4个发射天线的情况,当BER＝10(-3)时,BPSK和QPSK调制下本文所提QQOSTBC-CR分别比QOSTBC-CR有4.5dB和7dB的增益,分别比瑞利信道下QQOSTBC-CR有-4dB和-3dB的增益.     

Experimental Demonstration of a Holographic Demultiplexer With Low Polarization-Dependence Loss Using a Long-Period Diffraction Grating

We describe the results of a holographic demultiplexer (DeMux) focused on the low polarization-dependence loss (PDL) using long-period volumetric diffraction grating. A 0.8-nm-spaced 21-channel holographic DeMux with PDL of less than -0.38 dB, channel uniformity of 0.495 dB, and channel crosstalk of -13 dB has been demonstrated     

Gating demultiplexer integrated with MSM detector array inInGaAs/AlGaAs/GaAs for WDM

The authors demonstrate the integration of a grating demultiplexer with curved output waveguides and a MSM photodetector array in InGaAs/AlGaAs/GaAs operating in the 1-μm wavelength region. The structure provides 38 channels with 1-nm channel spacing. The total loss, including scattering from the unmetallized grating, is about 17 dB. A channel crosstalk of -11 dB is obtained. The FWHM of the channel pass band is 0.5 nm     

非线性光谱展宽载波的湍流信道高速传输特性

采用非线性光谱展宽光源作为高重复频率部分相干光载波光源,开展大气湍流信道中高速信息传输实验研究.通过皮秒光纤激光器泵浦高非线性光纤获得非线性光谱展宽的部分相干光载波光源,重复频率可达10 GHz.采用10 Gbit/s脉冲高速数字调制,通过模拟大气湍流信道传输,相干光载波和部分相干光载波在湍流信道传输前后的信噪比分别从...     

Flat-top silica-based arrayed waveguide grating with 40-channels

A wavelength multiplexer or demultiplexer plays ani mportant role in all wavelength division multiplexing( WDM) system.Silica-basedarrayed waveguide gratings(AWGs) offer attractive featuresinthis area due to theadvantage of large output channels and lowlo…     

干涉SAR模拟器通道幅相特性实时校正方法

干涉SAR模拟器是构建单航过InSAR系统地面半实物仿真系统的重要地检设备,模拟器通道幅相非理想特性会影响对干涉性能的准确评估.研究了基于实时滤波校正模拟器通道幅相特性的方法:采用相关加窗处理从闭环数据中提取通道幅相特性,提出了复Remez算法和遗传算法相结合的方法设计复FIR滤波器系数,采用FPGA实现高数据率数据的实时滤波.通过实时校正将模拟器通道间幅相一致性误差峰峰值从1 dB/10度量级提高至0.1 dB/1度水平,半实物试验验证了本文实时校正方法的有效性.     

High-performance InP reflection-grating wavelength multiplexer

A high-performance InP reflection-grating wavelength multiplexer for the 1530-1560 EDFA fibre band is reported. The 8 channel 3.6 nm-spacing devices operated with 30-35 dB channel isolation, <0.04 wavelength precision, and <10 dB on-chip loss. Although realised with 3.6 nm spacings, the multiplexer may be adapted for channels as close as 0.5 nm