Silicon photodetector structure for direct coupling of optical fibers to integrated circuits

A novel detector structure exhibiting real-estate efficient coupling of optical fibers to semiconductor devices is described. The integrated fiber-optic coupler employs vertical insertion of a tapered single-mode fiber into a laser-etched cylindrical hole in the substrate. It features a small surface footprint, mechanical stability, and accurate alignment. Fabricated in silicon, the p-n junction detectors have typically shown responsivities of 0.23 A/W at 0.63 µm, corresponding to a quantum efficiency of 45 percent, and dark currents below 1 nA.     

Efficient finite-element-based time-domain beam propagation analysis of optical integrated circuits

In this paper, a novel numerically efficient time-domain beam propagation method based on the versatile finite element method (FETDBPM) is presented for the analysis of arbitrarily shaped optical integrated circuits. Lumping the global mass matrix into a diagonal matrix, an explicit full band finite-element time-domain propagation algorithm that needs only matrix-vector multiplication at each time step is derived. The accuracy and efficiency of the proposed FETDBPM is demonstrated through the analysis of propagation in different photonic integrated structures.     

Ceramic capacitors for hybrid integrated circuits

Ruggedness, wide capacitance range, high volumetric efficiency, and relatively attractive cost have been the main reasons for the popularity of ceramic chip capacitors. Continuing improvements in most of these categories promise to keep the ceramic chip in its present position of prominence. This article considers multilayer, single-layer, and screened-on configurations. In addition, relationships between size, capacitance, and cost are covered for three common ceramic formulations (NPO, W5R, and Z5U).     

集成化故障检测电路设计

讨论了高频 (微波 )通讯系统中故障检测电路设计的一般方法及设计中应注意的问题 ,并给出了一个设计实例     

Efficient analysis of microstrip-coupled nonradiative dielectric(NRD) resonators for hybrid integrated circuits

Nonradiative dielectric (NRD) resonators have been recently known as excellent stabilizing components for the design of a new class of oscillators based on hybrid integration of planar circuits and NRD-guides. However, an accurate characterization of such a component is needed in order to develop efficient computer-aided-design programs. In this paper, a hybrid planar integrated circuit comprising an NRD resonator is accurately modeled and is coupled to input and output planar microstrip circuits by means of long slots located on the top ground plane of the NRD structure. A reciprocity approach is used to solve the coupling problem between the resonator and microstrip lines. A modal expansion of the field equations has been applied to the NRD resonator in obtaining its rigorous field expressions. Finally, a transmission-line analysis is proposed for the structure, and scattering parameters have been calculated for different slot positions. Results are discussed for various parametric effects on coupling and Q-factor characteristics     

Quasiplanar 3 dB hybrid for millimetre-wave integrated circuits

A quasiplanar 3 dB hybrid suitable for integration in millimetre-wave fin-line circuits is presented. The performance of the device is characterised by 0.5 dB insertion loss, less than 0.5 dB imbalance and 20?25 dB isolation over the entire Ka-band (26.5?40 GHz).     

Computer-aided design considerations for mixed-signal coupling inRF integrated circuits

This paper reviews computer-aided design techniques to address mixed-signal coupling in integrated circuits, particularly wireless RF circuits. Mixed-signal coupling through the chip interconnects, substrate, and package is detrimental to wireless circuit performance as it can swamp out the small received signal prior to amplification or during the mixing process. Specialized simulation techniques for the analysis of periodic circuits in conjunction with semi-analytical methods for chip substrate modeling help analyze the impart of mixed-signal coupling mechanisms on such integrated circuits. Application of these computer-aided design techniques to real-life problems is illustrated with the help of a design example. Design techniques to mitigate mixed-signal coupling can be determined with the help of these modeling and analysis methods     

Efficient methods for modelling substrate coupling in mixed-signalintegrated circuits

A key problem in the design of large mixed-signal circuits is the noise caused by the coupling of digital signals into the substrate. This paper describes methods that allow circuit designers to model efficiently such substrate noise in large mixed-signal SPICE designs. In the light of these techniques a new methodology is presented for efficiently modelling the substrate noise caused by current injection and its coupling to analogue signals; this is then extended to provide a real-time modelling capability. The practicality and the numerical efficiency of the methods are demonstrated on several prototype example circuits     

Interconnection systems for solid-state components in hybrid integrated circuits

The factors which can influence the performance and reliability of the interconnection system for solid-state components in hybrid integrated circuits are examined. The main emphasis is on materials that have received most attention in the tantalum film and silicon technologies in the Bell System. However, other materials that are being used are discussed. The interrelation of various factors in choosing an interconnection system is discussed. These factors include the composition of the materials, the methods of depositing various metals, and the properties of the substrates. Among the properties of the materials that are considered, emphasis is laid on environmental stability. The results of environmental tests on conductors and thin-film resistors under high-humidity conditions are reported. Some results on the use of silicone rubber as an encapsulant indicate this material is effective in reducing degradative action on hybrid circuits.     

Nondestructive optical technique for electrically testing insulated-gate integrated circuits

A simple nondestructive optical technique for electrically testing insulated-gate integrated circuits and for testing dielectric layers for pinholes and breakdown strength is described using a nematic liquid crystal in the dynamic scattering mode. Good correlation has been obtained between this technique and conventional electrical-probe test results. The technique has also proved particularly useful for fault locating and diagnosis.     

Picosecond optical sampling of GaAs integrated circuits

Direct electrooptic sampling is a noncontact optical-probing technique for measuring with picosecond time resolution the voltage waveforms at internal nodes within GaAs integrated circuits. The factors contributing to system bandwidth, sensitivity, spatial resolution, and circuit perturbation are discussed, as are the circuit requirements for realistic testing of analog and digital devices. Measurements of high-speed GaAs integrated circuits are presented, including time-domain waveform and timing measurements of digital and analog circuits and frequency-domain transfer function measurements of microwave circuits and transmission structures     

Modeling and analysis of substrate coupling in integrated circuits

This paper describes a fast and accurate simulator for characterizing the effects of substrate coupling on integrated-circuit performance. The technique uses the electrostatic Green function of the substrate medium and the fast Fourier transform algorithm. It is demonstrated that this technique is suitable for optimization of layout for minimization of substrate coupling. Analysis of substrate coupling in different types of substrates and the utility of guard rings in different types of substrates is also discussed. Experimental verification of the models is presented     

混合信号集成电路的衬底耦合噪声分析

本文系统分析了混合信号集成电路的衬底噪声耦合的研究进展.简要分析了衬底噪声的基本机理,及其对混合信号电路的影响,在此基础上分析比较了目前已提出的几种主要的衬底耦合噪声模型.通过分析不同类型衬底内的噪声耦合,介绍了一些电路设计中的去耦方法.最后讨论了衬底耦合噪声研究的发展方向.     

Thermal coupling in integrated circuits: application to thermaltesting

The power dissipated by the devices of a circuit can be construed as a signature of the circuit's performance and state. Without disturbing the circuit operation, this power consumption can be monitored by temperature measurements of the silicon die surface via built-in differential temperature sensors. In this paper, dynamic and spatial thermal behavioral characterization of VLSI MOS devices is presented using laser thermoreflectance measurements and on-chip differential temperature sensing circuits. A discussion of the application of built-in differential temperature measurements as an IC test strategy is also presented     

GaAs integrated optical circuits by wet chemical etching

An integrated optical circuit containing a laser, passive waveguide, and extra-cavity detector is described. These devices are fabricated from AlxGa1-xAs layers grown by liquid-phase epitaxy. Reflectors are formed by a two-step preferential etch procedure. For proper laser orientation on {100} wafers, the mirrors are found to be oblique, tapered so as to enhance coupling into the underlying passive waveguide; this increases the efficiency of radiation transfer to the detector. Device operation with high differential transfer efficiency and low threshold has been achieved; e.g., for devices with one etched mirror and one cleaved mirror, ηt= 16 percent andJ_{t} = 2.4kA/cm², whereas these values areeta_{t} = 6.5percent and Jt= 3.0 kA/cm²for devices with two etched mirrors. Other orientations on {100} and {110} wafers have also been investigated. The reflectivity of the etched mirrors is small,R_{e} simeq 1-2percent, but transfer efficiencies into the external passive waveguide as large asT = 50percent have been observed. The effect of small Reon device performance is examined both experimentally and theoretically. The fabrication of ribbed interconnections between active circuit components is also described.     

A family of perfect aspherical geodesic lenses for integrated optical circuits

An aspherical geodesic lens havingf = 4.5mm andf/number = 0.64 has been built and tested for use in integrated optics. Its capability to carry out the spectral analysis of a signal is discussed. This lens is a member of a family of theoretically perfect geodesic lenses, characterized by an arbitrary choice of two parameters. This allows one to match the properties of a lens to the particular application one has in mind.     

Efficient coupling in integrated twin-waveguide lasers usingwaveguide tapers

We demonstrate a 1.55-μm wavelength, InGaAsP-InP, twin-waveguide (TG) laser integrated with passive ridge waveguides using low-loss taper couplers. The lateral taper on the laser waveguide induces efficient resonant coupling of light between the active and passive layers. The device is fabricated using low-cost conventional photolithography and reactive ion etching of a TG structure grown by gas-source molecular beam epitaxy. This structure is suitable for integrating a variety of photonic devices without requiring epitaxial regrowth     

Time-resolved optical characterization of electrical activity in integrated circuits

If the rate of improvement in the performance of advanced silicon integrated circuits is to be sustained, new techniques for the measurement of electrical waveforms in operating circuits are needed. Critical factors dictating this requirement include the increased speed and complexity of circuits, the growing importance of faults that appear only during high-speed operation, and the use of flip-chip packaging technologies. Two recently developed all-optical methods for measuring the switching activity from the backside of a chip are described and compared. One is a passive approach based on the measurement of hot carrier luminescence emitted from the channel of a CMOS field-effect transistor (FET) during switching. The second uses a laser probe to sense the switching induced modulation of the silicon optical constants near an FET's source and drain.     

Liquid crystal variable optical attenuators integrated on planarlightwave circuits

Variable optical attenuators using polymer-network liquid crystal have been integrated with the pitch of 250 μm on planar lightwave circuits. Trenches are cut in the direction perpendicular to the parallel light waveguides into planar lightwave circuits, a transparent electrode is deposited inside the trenches, and the trenches are filled with polymer-network liquid crystal. The typical attenuation range is 18 dB when the driving voltage is <20 Vrms at 1.55-μm wavelength. The power consumption is estimated to be very low (200 nW/ch)