A novel monolithic HBT-p-i-n-HEMT integrated circuit with HBTactive feedback and p-i-n diode variable gain control

We report the world's first functional MMIC circuit integrating HBT's, HEMT's, and vertical p-i-n diodes on a single III-V substrate. The 1-10 GHz variable gain amplifier monolithically integrates HEMT, HBT, and vertical p-i-n diode devices has been fabricated using selective MBE and a merged processing technology. The VGA offers low-noise figure, wideband gain performance, and good gain flatness over a wide gain control range. A noise figure below 4 dB was achieved using a HEMT transistor for the amplifier stage and a wide bandwidth of 10 GHz. A nominal gain of 10 dB was achieved by incorporating HBT active feedback techniques and 12 dB of gain control range was obtained using a vertical p-i-n diode as a varistor, all integrated into a compact 1.5×0.76 mm² MMIC. The capability of monolithically integrating HBT's, HEMT's, and p-i-n's in a merged process will stimulate the development of new monolithic circuit techniques for achieving optimal performance as well as provide a foundation for high performance mixed-mode multifunctional MMIC chips     

用于光通信的GaAs集成电路

介绍了用于 1 0 Gb/s光传输系统前端模块的超细栅 Ga As FET器件的制作技术以及制作的数 /模 IC芯片组     

相位共轭反馈光波用于图像衬度控制

本文提出了一种利用双相位共轭反射镜的实时图像衬度控制方法。给出了理论分析,提出了一种实验方案,给出了模拟实验结果。     

Tracking control of electrostatically actuated micromirror with closed-loop feedback circuit

Presented is a closed-loop feedback control of an electrostatically actuated micromirror to track a moving light source and to stabilise fast the tilting angle. The micromirror has been designed and fabricated with single crystalline silicon. Tracking and tilt-angle stabilisation has been tested using a position-sensing detector and analogue feedback control circuit. Successful tracking of a moving light source was achieved. The feedback control has been also verified to improve the tilt-angle stabilisation time of the micromirror significantly.     

Loss-compensated optical Y-branch switch in InGaAsP-InP

An InGaAsP-InP loss-compensated Y-branch switch is demonstrated. Integrated amplifying sections compensate for internal losses. The operating wavelength is 1.3 μm, and the gating dynamic range is 35 dB. A study of similar devices indicates that a gain of more than 10 dB and a gating dynamic range in excess of 45 dB are feasible     

A temperature insensitive InGaAsP-InP optical filter

A temperature insensitive optical filter (TIOF) with InGaAsP-InP material system is proposed. Less than 0.1 /spl Aring///spl deg/C temperature dependence is achieved for the first time even though we used the InGaAsP-InP material system. By changing the optimum structure of the TIOF, blue-shift temperature characteristics are also obtained. These two novel phenomena are in good agreement with the TIOF design principle.     

Micromechanical optical switching with voltage control using SOImovable integrated optical waveguides

Optical switching is demonstrated using movable integrated optical waveguides fabricated on silicon-on-insulator substrates. The switching effect is produced by the voltage-controlled micromechanical deflection of the movable waveguides. The dynamic response of the deflection is studied. A contrast ratio of 12 dB of switching is obtained using an applied voltage of less than 10 V. At 20 V, the contrast ratio is about 40 dB     

InGaAsP/InP monolithic integrated circuit with lasers and an optical switch

InGaAs/InP monolithic integrated circuits composed of a compact carrier-injection optical switch and distributed feedback laser diodes are fabricated. These integrated circuits have a variety of functions, such as monolithic modulators, switches and optical amplifiers for optical communication systems.     

An optical integrated circuit for time-division 2-D velocitymeasurement

An LiNbO₃ optical integrated circuit pigtailed with two single-mode fibres, which allows time-division two-dimensional velocity measurement, is discussed. To detect time-division multiplexed beat signals corresponding to velocity components v_X and v_γ of a moving object, a waveguide switch is integrated on a Z-propagating LiNbO₃ substrate of 28×7 mm² in addition to a waveguide interferometer with a frequency shifter. In the optical IC, either v_X or v_γ could be measured selectively with signal-to-noise ratio of 20 dB by driving an electronic gate placed after a photodiode in synchronization with the waveguide switch     

Polysiloxane optical waveguide layer integrated in printed circuit board

A hybrid electrical-optical circuit board is demonstrated using polysiloxane as low-loss and high-temperature stable waveguide material system. After board lamination at 180/spl deg/C for two hours and a subsequent annealing at 230/spl deg/C for 5 minutes the waveguide insertion loss is 0.05 dB/cm at 850 nm wavelength.     

半导体激光器混沌电路延时反馈控制方法

由于当前方法未能建立物理模型,导致混沌电路延时反馈控制复杂度和控制耗时增加,容错率下降,为此提出一种半导体激光器混沌电路延时反馈控制方法。组建半导体激光器混沌电路延时反馈条件下激光器电流激发混沌的物理模型,获取激光器非线性增益和线宽增强因子特性,并获取控制延迟可控条件。分析延迟量和反馈增益的解析关系,获取目标周期轨道控制参数的分岔图,以此为依据进行半导体激光器混沌电路延时反馈控制。实验结果表明,所提方法能够有效降低混沌电路延时反馈控制复杂度和控制耗时,大幅度提升容错率。     

All optical switching of integrated hybrid distributed feedback bistable laser

A novel type of optical bistable circuit using both optical and electrical feedback to achieve bistable operation is reported. The circuit provides genuine optical gain, can be triggered by optical inputs over a large spectral range and minimises signal feedback to previous circuits.<>     

Electrically pumped InGaAsP-InP microring optical amplifiers and lasers with surface passivation

Vertically coupled electrically pumped InGaAsP microring optical amplifiers providing gain at 1550 nm are demonstrated. The microrings provide up to 10 dB of gain at the through-port in pulsed mode. The bias current is used to control the loss in the ring and, hence, the region of operation (under-coupled, critically coupled, transparency, and gain). Sulfur passivation is used to reduce carrier loss due to surface recombination in the active region. The amplifiers are designed for application in cascaded microring optical logic gates in photonic logic circuits.     

Linewidth broadening in a distributed feedback laser integrated with a semiconductor optical amplifier

The problem of the linewidth degradation in systems using distributed-feedback lasers together with strained-layer multi-quantum-well semiconductor optical amplifiers (SOAs) is examined. A modified expression for the linewidth in the case of anti reflection-coated SOA output facets is derived and simulation results are given in the case of output facets with a nonvanishing reflectivity. A numerical model combining finite-element calculations in the transverse x-y plane and a longitudinal model based on the Green's function method is used for that purpose.     

Adaptive fuzzy process control of integrated circuit wire bonding

One step in the assembly of integrated circuits is wire bonding, requiring expert knowledge to optimize critical process characteristics. This paper describes a fuzzy logic controller which sets parameters for the wire bonding process for gold ball wire bonds, specifically controlling bonded ball diameter and shear strength density. While the focus is on control of ball bonds, the method is general and may be applied to other bonding methods with minor modifications. The design of the fuzzy engine and the development of rules based on both operator experience and textual sources are discussed. An adaptation technique is developed to tune the controller's membership functions based on the measured results of the process. The controller has been tested on actual devices in an industrial setting; results show improved process control in terms of consistency and reduced operator adjustment     

High-current InGaAsP-InP phototransistors and some monolithic optical devices

High-gain InGaAsP/InP heterojunction phototransistors (HPT's) have been fabricated by a liquid-phase epitaxial (LPE) technique. A collector current as high as 170 mA has been achieved at a 2-V bias and a 155-µW incident-light power. The optical gain is 1180. A monolithic optical device has been constructed in a InGaAsP/InP system which includes the HPT and a double heterojunction (DH) light-emitting diode (LED). The monolithic optical device is designable as an optical switching and an optical bistable or a light amplification device by controlling positive feedback between the HPT and the LED. A light amplification system comprised of a discrete InGaAsP/InP laser diode and a high-current HPT, has exhibited incoherent-coherent conversion with a positive amplification.     

All-active InGaAsP-InP optical tapered-amplifier 1×N powersplitters

All-active tapered-amplifier power splitters (TAPS) consisting of a single-mode input waveguide, which acts as a preamplifier, a two-dimensional (2-D) diffraction section, which amplifies the signal during the splitting process, and N single-mode output waveguides, which act as post-amplifiers, were fabricated in 1.3-μm InGaAsP quantum-well material. Gains in each output guide (power out of guide/input power) of greater than 10 dB with a uniformity of better than 0.5 dB from guide to guide were measured on a 1×8 TAPS device     

采用双Y型LiNbO3集成光路的闭环光纤陀螺研究

集成化已成为研制中、高精度大动态范围光纤陀螺的一个必然途径。文中报道了一种采用光纤滤波/双Y型集成光路和全数字处理的闭环光纤陀螺,其中光纤滤波/双Y型多功能集成光路是采用退火质子交换法(APE)在铌酸锂衬底上制作而成的,它包含了光纤陀螺所需的除光纤线圈以外的无源光学器件的全部功能两个分光/合光器(耦合器)、两个宽带相位调制器(推挽工作)和一个高消光比的偏振器,测试结果表明,陀螺零偏稳定性优于1°/h。该陀螺结构紧凑、动态范围大、精度适中、成本低,特别适合于战术级的应用。