Standard-compliant jitter transfer function of all-optical clock recovery at 40 GHz based on a quantum-dot self-pulsating semiconductor laser

This letter reports on all-optical clock recovery over 40-Gb/s signal using a quantum-dot (QD)-based self-pulsating (SP) laser. In particular, the jitter transfer function from the input signal to the recovered clock is measured for the first time. We clearly demonstrate that, thanks to the narrow spectral linewidth of the free-running SP signal, the QD-based laser allows the suppression of high frequency jitter, and the cutoff frequency is exactly that required by the ITU-T recommendation G825.1 at 40 GHz.     

160 GHz actively modelocked semiconductor laser

A 163.66 GHz optical pulse train was generated by a semiconductor modelocked laser integrated with a high-mesa EA modulator, which enables direct synchronisation with a 81.83 GHz electrical signal. A timing jitter of 0.15 ps and low amplitude modulation noise are achieved.     

Broadband microwave photonic phase shifter based on polarisation rotation

A broadband microwave photonic phase shifter is presented based on the polarisation properties of a Mach-Zehnder intensity modulator and nonlinear polarisation rotation in a semiconductor optical amplifier. The system can realise about 150deg phase shift in the frequency range from 50 MHz to 19 GHz.     

Microwave phase shifter based on high-Tc superconductingfilms

A new microwave 180° phase shifter containing switching high-T _c elements is presented. Its operating principle is based on the fast film switching from the superconducting (S) state to the normal conducting (N) state under controlling overcritical current pulses. The problem of irreversible destruction of the S-N high-T_c film elements is solved by using specially shape controlling current pulses     

Electrically tunable microwave phase shifter based on layeredferrite-ferroelectric structure

Based on surface spin wave propagation in a layered structure containing ferrite and ferroelectric materials. Operating characteristics of the phase shifter are investigated theoretically. It is shown that waveguiding elements from planar layered ferrite-ferroelectric structures allow the construction of compact devices with high electrical tunability achieving 10°/V     

Digital reflection-type phase shifter based on a ferroelectricplanar capacitor

Novel design of an integrated digital reflection-type phase shifter based on a Barium Strontium Titanate thin-film capacitor is presented. Measured characteristics of the phase shifter are compared with the theoretically predicted ones     

基于光移相器的全光正交频分复用技术研究

为了克服光正交频分复用系统中傅里叶变换和数模转换实现的＂电子瓶颈＂,达到提高系统传输速率的目的,采用光延迟器和光移相器构建全光离散傅里叶逆变换（IDFT）和离散傅里叶变换（DFT）的方法,设计一个3路全光IDFT/DFT模块,利用Optisystem软件平台仿真实现一个3×40Gb/s的全光正交频分复用实验系统,并分析系统性能,获得发射光脉冲宽度与系统传输误码率的关系,得到了光脉宽越大误码率越大的结论。     

External-cavity semiconductor laser with 1000 GHz continuouspiezoelectric tuning range

A 1000-GHz continuous tuning range is achieved using a single piezoelectric transducer to orient a diffraction grating in an external-cavity semiconductor laser. The laser output power ripple versus wavelength is 15%, and the linewidth is less than 500 kHz. Large-amplitude piezoelectrically controlled wavelength modulation can be done at modulation frequencies on the order of 100 Hz. The maximum modulation frequency, continuous electrical tuning range, and linewidth are limited by the mechanical design of the external cavity. This device should have wide application in spectroscopy, metrology, and remote sensing     

基于单边带时间调制的CMOS有源移相器设计

为满足低成本相控阵对高精度波束扫描的需求,提出了一种基于单边带时间调制(single-sideband time-modulation, STM)的CMOS有源移相器.基于Global Foundries 0.13μm CMOS工艺,设计了双相调制单元用于I路和Q路的0°/180°移相,以抑制时间调制所产生的基频和偶次边带;设计了矢量合成与复用放大单元,在不增加功耗的前提下提高了整个电路增益;设计了偏置与时序控制单元,通过对I路和Q路增益的时序控制,实现了STM.仿真结果表明：本设计在1.8 V电源电压下的功耗为15.8 mW,在3-dB带宽（13.2～20.7 GHz）内的增益为-3±1.5 dB;在10～25 GHz频段内,实现了小于0.1°的移相偏差均方根（root mean square,RMS）和小于0.02 dB的增益偏差RMS,相位分辨率达10 bit以上;最大无用边带（-7次边带）的功率抑制比为16.7 dBc.该有源移相器具有低成本、低功耗、低相位偏差、低幅度偏差和低插入损耗等性能,为时间调制阵列提供了一种新颖的单元结构.     

A hybrid phase shifter circuit based on TlCaBaCuO superconductingthin films

A superconductor-semiconductor hybrid reflection-type phase shifter circuit has been designed, fabricated, and characterized for 180° phase bit with center frequency of 4 GHz and bandwidth of 0.5 GHz for operation at 77 K. All of the passive components of the phase shifter circuit such as input/output feed lines, 3 dB Lange coupler, impedance matching networks, and transmission lines consisted of thallium based superconducting TlCaBaCuO thin films of 4000 Å thickness on lanthanum aluminate substrate. Metal-Schottky field-effect-transistors (MESFET's) on GaAs semiconductor were used as active devices for switching action (on-state and off-state) in the phase shifter circuit. The phase shift and insertion losses were investigated as a function of frequency from 3.6 to 4.6 GHz at 77 K. The circuit exhibited a fairly flat response of 180° phase shift with a maximum deviation of less than 2° and a maximum insertion loss of 2 dB for on-state and 2.2 dB for off-state conditions over 0.5 GHz bandwidth at 4 GHz. The insertion losses were also fairly flat within the bandwidth. The insertion losses were constant between 50 and 80 K, giving the circuit a large range of operation at or below 77 K. The performance of this circuit as compared to a gold microstrip-semiconductor circuit designed identically was superior by a factor of 1.5, and may be due to lower conductor losses and lower surface resistance in the superconducting microstrips     

10 GHz optical receiver using a travelling-wave semiconductor laser preamplifier

A 1.5 ?m optical receiver with a bandwidth of 10 GHz has been demonstrated. The receiver used a travelling-wave semiconductor laser preamplifier and had an equivalent input noise of 1 pA/?Hz) with a 3 dB bandwidth of 10 GHz. The estimated sensitivity at 15 Gbit/s was ?27 dBm.     

Phase dynamics of semiconductor optical amplifiers at 10-40 GHz

The phase dynamics that occur in bulk InGaAsP-InP semiconductor optical amplifiers (SOAs) in response to picosecond pulse excitations at 10 and 40 GHz are studied experimentally and numerically for various amplifier lengths. The time dependencies of the phase changes and of the absolute gain of the amplifier are measured simultaneously. The total phase shifts induced by 1.5-ps pulses at 10 GHz are higher than /spl pi/ in SOAs with active region lengths between 0.5 and 2 mm and exceed 2/spl pi/ in a 1.5-mm-long amplifier. Phase shifts above /spl pi/ are measured at 40 GHz in 1.5- and 2-mm-long SOAs. The dependence of the total phase shift on the amplifier bias current and length and on pump pulse energy is investigated. Numerical simulations based on a comprehensive time-domain SOA model allow us to confirm the experimental results for a wide range of amplifier parameters. In particular, SOAs with lengths up to 5 mm have been modeled, and the calculations suggest that the maximum phase shifts occur in amplifiers of approximately 2-mm length. The phase dynamics measurements are illustrated at the example of an optical time division multiplexing add-drop multiplexer, based on a SLALOM switch, gated by 10- or 40-GHz control pulses. We find that simultaneous good dropping and clearing is possible if the length and the operating conditions of the SOA in the switch are chosen such as to induce a full /spl pi/ phase shift.     

Low power digital TTL command for 1 bit 60 GHz RF MEMS phase shifter

This paper presents a circuit used to actuate Radio Frequency MicroElectroMechanical Systems (RF MEMS) based phase shifters for 60 GHz beam forming. Wireless transmission in the 60 GHz band show a dramatic free space loss, thus making it mandatory to use antennas with high gain in a desired direction. Beam forming is then necessary to optimize the link budget between communicating nodes. Antenna arrays can be used for beam forming. The work done at LAAS was aiming to provide RF MEMS based phase shifters working with a standard digital command. RF MEMS commonly have high actuation voltages usually obtained with charge pumps. This paper presents a full 1 bit phase shifter with a digital translation part, an analog DC–DC converter, and an RF MEMS based loaded line phase shifter for 60 GHz signals. This converter is built using boost converters as an alternative to the use of charge pumps for driving RF MEMS in the field of wireless communications. Boost converters, despite relatively high current peaks, allow shorter settling times compared to charge pumps.     

40 GHz actively modelocked polarisation maintaining erbium fibrering laser

The first polarisation-maintaining actively modelocked erbium fibre ring laser (ML-EFRL) operating at a base rate of 40 GHz is presented. The laser generates highly stable and virtually transform-limited 1.2-1.9 ps pulses tunable over 40 nm with a timing jitter of <0.1 ps. These represent the shortest pulses and lowest timing jitter generated by a 40 GHz ML-EFRL     

A low-cost 8 to 26.5 GHz phased array antenna using a piezoelectrictransducer controlled phase shifter

A new phased array antenna of wide bandwidth and good beam scanning angle has been developed using a low cost multiline phase shifter controlled by a piezoelectric transducer (PET) and a stripline fed Vivaldi antenna array. The multiline progressive PET phase shifter has a low perturbation loss of less than 2 dB and a total loss of less than 4 dB up to 40 GHz with a maximum phase shift of 480°. The proposed phased array antenna consists of four E- or H-plane Vivaldi antennas, a PET phase shifter, and a power divider. The phased array shows a wide beam scanning capability of ±27° over a wide bandwidth from 8 to 26.5 GHz covering X, Ku, and K bands     

一种基于改进型全通网络版图结构的UWB GaAs移相器

针对移相器带宽受限的问题,设计了一种用于拓展移相器工作带宽的改进型全通网络版图.在传统全通网络版图的基础上引入一个用于调谐全通网络(All-pass Network,APN)中两个电感之间互耦系数的电容,该电容可以作为一个自由设计量,因此该结构可以提升全通网络的设计灵活度.为了验证该设计思路,仿真、加工并测试了两个工作...     

基于加载线型的平面太赫兹移相器设计

移相器是相控阵系统中的重要组成器件,随着频率的增加,金属的趋肤深度及波导表面粗糙度对器件的影响不可忽略,会使移相器的损耗增加。对此,提出一种基于加载线型的平面太赫兹移相器。将2个枝节并联在微带线上,在并联枝节上加载开关二极管,调节两段枝节的电长度得到所需的移相量;控制开关的导通和断开,实现不同的移相角度。仿真结果表明,在192~210 GHz频带范围内,导通和断开的反射系数都小于-10 dB,插入损耗小于0.5 dB,移相误差小于5°,其中在5 GHz带宽范围内,移相误差小于1°。提出的平面型移相器,加工容易,成本低,便于系统集成化,在太赫兹相控阵系统中具有广泛的应用前景。     

基于矢量和的微波光子移相器研究

基于矢量和（vectorsum）原理,利用50：50光纤耦合器、可变光延时线（VDL）、可变光衰减器（VOA）构建了微波光子移相器。以宽带光为载波有效地解决了合波处光波相位不同引起的微波信号不稳定的问题;利用马赫-曾德（M—Z）LiNbO3调制器在不同工作电压下的反相调制特性,设定调制器的不同偏置电压,同时配合调节两支...     

Microbend fiber-optic phase shifter

The use of spatially periodic microbend transducers to produce phase shift in single-mode fibers has been investigaed. Phase shift of32deg/mum²of transducer displacement per centimeter of trans-3.7deg/mum². cm for a 1023-μm peroid. Phase shifts as large as 560°/cm of transducer length were obtained with the shorter period transducer. These results are compared with predictions based on coupled-mode theory.