增强型单边带调制器的设计与实现

介绍了一种增强型单边带调制器 ,普通单边带调制器可使无用镜像边带抑制 2 5dB左右 ,而增强型单边带调制器进一步应用了I/Q正交网络原理 ,将两只普通单边带调制器组合应用 ,使无用镜像边带抑制度提高到约 3 5dB。     

Ka 波段宽带单边带调制器集成电路的设计

基于相移法实现SSB(单边带)调制器理论,设计制造了一种Ka 波段宽带SSB 调制器集成电路。对相移法产生单边带调制信号的原理进行了分析,利用无源电路的3D 电磁仿真分析和ADS 整体电路非线性仿真相结合的方法对调制器进行了优化。设计制造的90°相移电桥网络和同相合成器满足了产生Ka 波段SSB 信号的幅相要求,同时给出了测试结果。调制器在30 ~36GHz 频带内插入损耗臆14dB;载波和对称边带抑制逸15dB;其它边带抑制逸13dB;输入1dB 压缩功率38dBm;外形尺寸18mm×6mm。这种相移法单边带调制器不需要带通滤波器,具有电路简单,载波抑制比高,对相位误差要求不高的优点。     

高性能硅和铌酸锂异质集成薄膜电光调制器 （特邀）

硅基光子集成平台因其高集成度、CMOS工艺兼容性等特点在光通信领域受到了广泛的关注，而电光调制器作为光通信系统中最为重要的器件之一，承担着将电信号加载至光信号上的关键作用，为打破硅基调制器的性能限制，可利用硅和铌酸锂的大面积键合技术以及铌酸锂低损耗波导刻蚀技术实现高性能硅和铌酸锂异质集成薄膜电光调制器，目前该类调制器的性能可达半波电压3 V，3 dB电光带宽超过70 GHz，插入损耗小于1.8 dB, 消光比大于40 dB。文中对比了硅和铌酸锂异质集成调制器的研究现状并介绍了该异质集成薄膜调制器的结构设计与工艺实现方法。     

一种新型的单边带调制技术

从理论和实验两方面研究了一种新型单边带调制(SSB)技术,通过在中心站合适设置单臂强度调制器的偏置电压,使调制器产生的奇数边带被抑制,采用滤波器滤除其中的一个二阶边带,即可产生单边带信号.用该新型的单边带调制技术产生的光毫米波理论上可以传输148 km.同时搭建了实验系统,采用10 GHz的本振信号源与2.5 Gbit/s的数字信号混频后驱动单臂强度调制器产生抑制奇数边带的调制信号,再通过一个滤波器得到20 GHz的单边带毫米波,还得到了不同载波边带比(CSR)情况下的毫米波眼图.通过实验分析不同载波边带比对传输性能的影响,发现载波边带比为0 dB时,传输性能最佳.     

应用于光子集成的硅基混合集成人工微结构硅波导输出激光器研究

目前,硅光子集成在光通信和信号处理、微电子系统的片内和片间互连领域成为研究热点。虽然其基础元件如波导、输入/输出(I/O)耦合器、波分复用器、调制器和光探测器性能达到了一定水平,但是硅光子集成回路仍面临挑战,原因是硅基激光光源的制作仍然是一个技术难题。综述了近年来硅基混合集成激光器的进展,介绍了课题组的研究成果。将微结构引入到硅基混合集成硅波导输出激光器中,提出了新型的III-V/硅混合集成的微结构硅波导输出单模激光器。此新型激光器工作在通信波段。其中,InGaAlAs增益结构是通过晶片直接键合的方式与具有微结构的SOI(Si/SiO2/Si)集成。激光器模式选择机制是基于SOI中的周期微结构,仅通过标准光刻即可实现。微结构激光器室温连续输出为0.85mW,脉冲输出为3.5mW,边模抑制比为25dB。     

11GHz微波光子信号的单边带布里渊选择放大实验研究

提出一种实现11GHz微波光子信号单边带布里渊选择放大的简单系统,对该系统进行了研究,理论分析了11GHz微波光子信号下边带的光功率变化,通过实验实现了11GHz微波光子信号的单边带选择放大,得到了30dB单边带增益。对实验测得的边带光功率随泵浦波光功率的变化进行了讨论,实验结果和理论计算相吻合。     

基于光子芯片的微波光子混频器 （特邀）

提出了一种由光生本振单元和波长分离调制单元组成的微波光子混频方法,并在绝缘体上硅材料上设计实现了上述波长分离调制芯片。该芯片集成了硅基相位调制器、微环滤波器、光电探测器、光耦合器和光栅耦合器。实验搭建了基于该波长分离调制芯片的微波光子次谐波混频系统,结果表明,该微波光子混频器可以将6~16 GHz的RF信号变频到33~23 GHz。此外,针对实验系统中残留的混频杂散,分别提出了增加微环滤波器抑制比降低泄露光生本振强度和引入光移相器修正泄漏光生本振相位两种解决方案。通过仿真验证可知,引入光移相器的方法更为简单,更适合于光子集成芯片。     

基于氮化硅微环和载波分离的可重构微波光子带通滤波器

基于Add-Drop型氮化硅微环滤波器,利用光学单边带调制和光载波分离的方法,实现可重构微波光子带通滤波器。滤波器带宽和带外抑制比分别达到726 MHz和37.0dB。并且通过改变光载波波长实现1.64~23.41GHz的滤波器频率调谐;通过调节微环耦合系数实现0.683~2.246GHz的滤波器带宽调谐,在带宽调谐范围内带外抑制比大于26dB。     

SiGe电光调制器研究进展

光子调制器是光纤通信系统中的核心器件,主要对光信号进行调制,实现信号从电域到光域的转换。随着硅基半导体工艺的发展,硅基光子调制器逐渐成为了主流硅光子器件,基于硅工艺技术的GHz带宽调制器的实现也为硅光子学的发展奠定了基础。作为一种用于短距离光互连的高性能光调制器,SiGe光吸收调制器受到了较多关注。文中讨论了高性能SiGe电光调制器的发展现状,对国内外硅基光子调制器的研究进展进行分析,讨论了PIN、PN结等电学调制结构,为研发高速率、低损耗的光子调制器提供了思路。     

基于光子晶体和纳米线波导的马赫-曾德尔型调制器

提出了一种基于光子晶体和纳米线波导的马赫-曾德尔型调制器.该调制器由硅基光子晶体平板波导、纳米线波导和光子晶体多模干涉耦合器(MMI)构成。在光子晶体与纳米线波导连接处采用了锥型结构,用于减少模式失配造成的损耗。利用时域有限差分法(3D-FDTD)进行仿真分析,结果表明,该调制器在工作波长1 550 nm下的插入损耗为0. 3 dB,消光比为15. 1 dB,器件尺寸仅46μm×8μm×0. 22μm,调制带宽可以达到68 GHz,且工作区域覆盖了以1 551 nm为中心波长20 nm的通信波段。该调制器结构紧凑,易于集成,可应用于高速光通信系统。     

Design and Characterization of a 211–275 GHz Sideband Separating Mixer for the APEX Telescope

We present the final results of the development and characterization of the sideband separating superconductor-insulator-superconductor (SIS) mixer for the APEX telescope band 1 (211-275 GHz). The sideband separation is achieved by using a quadrature scheme where the radio frequency (RF) and a local oscillator (LO) power are applied to two identical double sideband SIS mixers. All mixer components, including the LO and RF distribution circuitry, are integrated into a single mixer block. To achieve a compact design we developed a superconducting Lange coupler, based on Nb thin film, which is used as an intermediate frequency hybrid. Typical single sideband noise temperature of 100 K and sideband rejection ratio of about 12 dB and are measured.     

Hybrid ring coupler for W-band MMIC applications using MEMS technology

The hybrid ring coupler was designed and fabricated on a GaAs substrate using surface micromachining techniques, which adopted dielectric-supported air-gapped microstrip line (DAML) structure. The fabrication process of DAML is compatible with the standard monolithic microwave integrated circuit (MMIC) techniques, and the hybrid ring coupler can be simply integrated into a plane-structural MMIC. The fabricated hybrid ring coupler shows wideband characteristics of the coupling loss of 3.57 /spl plusmn/ 0.22dB and the transmission loss of 3.80 /spl plusmn/ 0.08dB across the measured frequency range of 85 to 105GHz. The isolation characteristics and output phase differences are -34dB and 180/spl plusmn/1/spl deg/, at 94GHz, respectively.     

Gigahertz-bandwidth InGaAsP/InP optical modulators/switches with double-hetero waveguides

A new kind of InGaAsP/InP electro-optic directional coupler modulator/switch with double-hetero plano-convex waveguides, which is suitable for monolithic integrated optics, has been proposed and demonstrated. The fabricated devices have shown low optical loss (4 dB/cm) and high modulation bandwidth of 1 GHz at 1.3 ?m wavelength.     

Design and analysis of CMOS broad-band compact high-linearity modulators for gigabit microwave/millimeter-wave applications

CMOS broad-band compact high-linearity binary phase-shift keying (BPSK) and IQ modulators are proposed and analyzed in this paper. The modulators are constructed utilizing a modified reflection-type topology with the transmission lines implemented on the thick SiO/sub 2/ layer to avoid the lossy silicon substrate. The monolithic microwave integrated circuit (MMIC) chips were fabricated using standard bulk 0.13-/spl mu/m MS/RF CMOS process and demonstrated an ultracompact layout with more than 80% chip size reduction. The broadside couplers and 180/spl deg/ hybrid for the modulators in the CMOS process are broad-band designs with low phase/amplitude errors. The dc offset and imbalance for the proposed topology are investigated and compared with the conventional reflection-type modulators. The measured dc offset was improved by more than 10 dB. Both BPSK and IQ modulators feature a conversion loss of 13 dB, a modulation bandwidth of wider than 1 GHz, and second- and third-order spur suppressions of better than -30 dBc. The IQ modulator shows good sideband suppression with high local-oscillator suppression from 20 to 40 GHz. The modulators are also evaluated with a digital modulation signal and demonstrate excellent modulator quality and adjacent channel power ratio.     

一种小型化电调正交耦合器

该文提出了一种3dB正交电调耦合器。该耦合器基于传输线变换技术进行设计,利用变容二极管调节3dB正交耦合器的中心频率,实现了从1.8~2.8GHz的中心频率调节范围,在可调范围内实现S11优于-15dB,S31大于-4.4dB,直通和耦合端的相位差为90±5°。该耦合器具有结构紧凑,偏置电路简单的优点。     

A 3.1-4.8 GHz transmitter with a high frequency divider in 0.18 μm CMOS for OFDM-UWB

A fully integrated low power RF transmitter for a WiMedia 3.1-4.8 GHz multiband orthogonal frequency division multiplexing ultra-wideband system is presented. With a separate transconductance stage, the quadrature up-conversion modulator achieves high linearity with low supply voltage. The co-design of different resonant frequencies of the modulator and the differential to single (D2S) converter ensures in-band gain flatness. By means of a series inductor peaking technique, the D2S converter obtains 9 dB more gain without extra power consumption. A divided-by-2 divider is used for carrier signal generation. The measurement results show an output power between -10.7 and -3.1 dBm with 7.6 dB control range, an OIP3 up to 12 dBm, a sideband rejection of 35 dBc and a carrier rejection of 30 dBc. The ESD protected chip is fabricated in the Jazz 0.18/zm RF CMOS process with an area of 1.74 mm~2 and only consumes 32 mA current (at 1.8 V) including the test associated parts.     

Optical mm-Wave Signal Generation by Frequency Quadrupling Using an Optical Modulator and a Silicon Microresonator Filter

By adjusting the direct current (dc) bias on an electrooptic modulator to suppress the first-order sideband and subsequently using a double-waveguide micro-ring resonator to filter out the optical carrier, millimeter (mm)-wave signal was generated at a frequency of four times the 10-GHz local oscillator. A monolithic integrated silicon-based optical mm-wave signal generator by frequency quadrupling is proposed. A silicon integrated microresonator filter was fabricated and its design parameters are given. High extinction ratio optical mm-wave signal was obtained. The single sideband noise spectrum of the generated 40-GHz optical signal was measured, showing similar performance when compared with that generated by a radio-frequency synthesizer.      

Millimeter-Wave Lange Coupler Design and Its Application in the Monolithic Image Rejection Mixer Design

This paper reports on the design of a Ka-band monolithic Lange coupler and its application in the monolithic fourth-harmonic image rejection mixer. Detailed design and analysis using Ansoft-HFSS simulator have been carried out. The simulated results of the Lange Coupler show the insert loss is better than ?3.64 dB; the amplitude balance is less than 0.55 dB and the phase balance is less than 0.65° from the 90° phase difference over the 30 to 40 GHz frequency range. The Lange Coupler is employed in a monolithic image rejection mixer that is fabricated by a commercial 0.18-μm pseudomorphic high electron-mobility transistor (pHEMT) process. The chip size is 1.4 mm × 1.9 mm. The image rejection ratio (IMR) is from 15 to 34 dB in the RF frequency range of 30 to 40 GHz.     

Ka Band Broadband Fourth Harmonic Image Rejection Mixer

This paper presents the design and implementation of Ka band broadband hybrid integrated image rejection mixer with a fourth harmonic mixer as unit mixer. Detailed design and analysis have been carried out. The mixer was fabricated by hybrid microwave integrated circuit (HMIC) process based on the thin film ceramic substrate which can reduce the cost compared to monolithic microwave integrated circuit (MMIC). The measured results showed conversion loss less than 11.2 dB and image rejection ratio (IRR) more than 20 dB in 4 GHz RF bandwidth. It can also play the role of up-converter from the test data.