2.8kV、140ps高压电脉冲的产生

研制了雪崩二极管脉冲成形电路,简述了此电路的工作原理,用此线路产生了幅度2.8kV、宽度140ps的高压电脉冲。     

一种超宽带脉冲发生器的设计与仿真

利用双极型晶体管的雪崩特性设计了双管并联的超宽带（Ultra-Wideband，UWB）脉冲发生器，通过添加电感使电路的等效负载增加，在维持脉冲宽度基本不变的情况下使输出脉冲的幅度增加到原来的2．5倍。对电路中各元件参数的选取进行详细的分析说明，给出了参数值与脉冲各项性能的关系。仿真得到的UWB脉冲信号幅度为-38．299V，脉冲宽度约为663．265ps，上升时间459．184ps，下降时间约为969．388ps。     

Subnanosecond rise time pulses from injection lasers

The hybrid integration of an injection laser with a simple avalanche transistor modulator is shown to produce optical peak powers of several tens of watts magnitude and pulse rise times appreciably shorter than 1 ns. In certain circumstances the pulse leading edge assumes the form of a spike having a displayed rise time of 120 ps.     

超快速高压雪崩三极管器件研制

采用雪崩三极管MARX电路易产生亚纳秒导通前沿的高功率微波脉冲,可应用于激光LED驱动、超快脉冲前沿发生器和高速脉冲发生器等。介绍了雪崩三极管器件的工作原理及设计方法,采用针对雪崩模式工作的npn晶体管的特殊工艺设计,研制出了耐压400V,脉冲电流达80A的雪崩三极管器件并已投入批量生产。给出了雪崩三极管MARX使用电路及测试结果,重复频率可达400kHz。器件采用金属管壳片式封装,具有可靠性高、易于级联使用等优点。     

Low dark-current, high gain GaInAs/InP avalanche photodetectors

High performance inverted-mesa GaInAsP/InP avalanche photodiodes responding out to 1.25 μm have been fabricated. Uniform avalanche gainsM, of 700 dark-current densities of3 times 10^{-6}A/cm²atM = 10, and an excess noise factor of ∼3 atM = 10have been achieved by placing the p-n junction in the InP and using a new passivation technique. Pulse-response rise times of less than 160 ps, limited by the rise time of the mode-locked Nd:YAG laser pulse, were measured with an avalanche gain of 40.     

纳秒脉冲半导体激光驱动器的研究

为了获得高功率、高重复频率的纳秒级光脉冲,介绍了一种基于Marx bank脉冲发生原理的纳秒脉冲激光驱动器的设计,以及设计过程中雪崩晶体管的选取.该驱动器采用一级小雪崩管对触发脉冲进行陡化,由小雪崩管产生的脉冲对Marx bank电路进行触发,以获得大电流窄脉冲,用于驱动半导体激光器.设计所得驱动器的峰值电流为12.5A、半峰全宽为1.51ns、重复频率为100kHz,实现了大幅度纳秒脉冲半导体激光驱动器的设计要求.结果表明,对触发脉冲的陡化,可以降低后一级Marx bank电路的雪崩电压,同时使得脉宽更窄,这将更加有利于驱动半导体激光器.     

Experimental analysis for the large-amplitude high-efficiency mode of oscillation with Si avalanche diodes

This paper presents the result of an investigation aiming to clarify the large-amplitude oscillation mechanisms of a Si avalanche diode with high efficiency, a part of which was already reported in [6], by varying circuit conditons and the shapes of applied voltage pulses. Applying a pulse resistive, transient voltage across and current through the diode have been observed by varying the rise time of the source voltage. As a result, variations of these waveforms have been revealed with decreasing the rise time and if the slope of the diode voltage at the breakdown is large than 100 V/ns, damping oscillation has been observed with the amplitude increasing proportionally to this slope. This damping oscillation plays a significant role in initiating the stable large-amplitude oscillation. Using a resonant cavity, voltage and current waveforms at various points have been observed and analyzed for various cavity lengths and applied source voltages. The analysis shows that the voltage wave-form across the diode coincides with the superimposed waveforms of the wave incident on and the wave reflected from the diode, the latter being delayed about 60 ps with respect to the former. This oscillation mechanism is considered to be very close to the TRAPATT oscillation. The details of experimental results, oscillation characteristics, and their analyses are explained.     

Frequency modulation mode-locking and Q-switching of diode-laser-pumped Nd:YLF laser

Using frequency modulation (FM) mode-locking techniques, and pumping with a 500 mW laser diode, the authors have developed a Nd:YLF (yttrium lithium fluoride) laser operating at 1053 nm that produces 49 mW average power in pulse durations of 9 ps. When this system is Q-switched, the energy within the 90 ns pulse envelope is 17 mu J. The average mode-locked pulse duration within this envelope is 21 ps giving rise to a peak power of 22 kW.<>     

Electrooptic sampling evaluation of 1.5 μmmetal-semiconductor-metal photodiodes by soliton compressedsemiconductor laser pulses

An electrooptic sampling system using soliton compressed pulses from a gain switched laser diode was assembled and used to characterize an InGaAs metal-semiconductor-metal photodetector at the important optical fiber wavelength of 1.55 microns. The measured rise time of the photodiode pulse was 6.5 ps. The pump and probe pulses had a FWHM of 0.6 ps as measured by autocorrelation. The sampling system rise time was evaluated to be 2.0 ps, yielding the estimated intrinsic photodiode rise time of 2.3 ps. By introducing a differential detection scheme and optical filtering, a shot noise limited sensitivity of 0.6 mV/Sqrt[Hz] was achieved. These results represent the fastest rise time, and most sensitive semiconductor laser based, electrooptic sampling system reported to date     

Single-photon avalanche diode with ultrafast pulse response freefrom slow tails

A single-photon avalanche diode (SPAD) with a novel structure is presented. The slow tail in the pulse response, which plagued the performance of previous ultrahigh-speed SPADs, has been eliminated. The pulse response is cleaner and sharper than that of the fastest microchannel-plate photomultipliers, making the new devices almost ideal for photon timing measurements on fast optical waveforms. The typical photon detection efficiencies are 16% at 630 nm and 4% at 850 nm, and the timing resolution of the 8-μm devices is 45 ps full width at half maximum (FWHM). Unprecedented performance is demonstrated: just 300 ps after a light pulse, a signal three orders of magnitude weaker can be easily measured     

Silicon avalanche photodiodes with low multiplication noise and high-speed response

Low-noise and high-speed silicon avalanche photodiodes with low breakdown voltage are reported. The diode structure with a low-high-low impurity density profile is proposed to have low-noise characteristics. Multiplication noise and depletion layer width of several structures are compared theoretically, and effects of impurity density profile of the avalanche region are discussed. Built-in field is also provided to realize high-speed response without increasing operating voltage. Silicon avalanche photodiodes with the above mentioned structure have been fabricated with long time substrate annealing, ion implantation, and epitaxial growth. Attained performances are as follows: noise parameter k = 0.027 - 0.040, output pulse half width τ = 260 ps for a mode-locked Nd:YAG laser pulse, gain-bandwidth product up to 300 GHz at M = 400, quantum efficiency 0.55 - 0.66 at the 0.81- to 0.83-µm wavelength, and breakdown voltage about 100 V.     

Double epitaxy improves single-photon avalanche diode performance

A new single-proton avalanche diode (SPAD) with double-epitaxial silicon structure is presented. The device has a time response with short diffusion tail (270 ps time-constant), high resolution (45 ps FWHM, full-width at half maximum of the peak) and low noise, i.e. low-dark-count rate.<>     

Simulation studies in both the frequency and time domains of InGaAsP-InP avalanche photodetectors

The purpose of this brief is to analyze the relation between the physical structure of the quaternary InGaAsP avalanche photodetector and the speed of temporal response. The small-signal time-domain differential equations dealing with the current multiplication in a p-n junction structure operating in the avalanche mode are obtained. The structure is a mesa diode made of an n-type quaternary material In1-xGaxAsyP1-ygrown on a heavily doped InP substrate. For the first time, both magnitude and phase of the frequency response are computed in a frequency band extending up to 256 GHz, from which the time-domain impulse responses are obtained. Simulation studies are performed using light pulses with an FDHM of 48.8 ps and a base duration of 97.7 ps. The FDHM of the detected waveform is less than 70 ps, and the leading edge duration is less than 100 ps.     

Characteristics of germanium avalanche photodiodes in the wavelength region of 1-1.6 µm

Dark current, quantum efficiency, multiplication noise, and pulse response of germanium avalanche photodiodes with n+-p junction were studied to find an optimum structure. The dark current can be separated by graphical means into a leakage current component and a multiplied component which flows through the junction. The dark current components are also evaluated by using diodes with various diameters. The quantum efficiency and the multiplication noise are shown to be strongly affected by the n+ layer thickness. An n+ layer thickness optimized for signal-to-noise ratio is estimated from experimental and calculated results, using a figure of merit for avalanche photodiodes. The response waveform for mode-locked Nd:YAG laser shows a rise time of 100 ps and a half pulsewidth of less than 200 ps.     

可用于光纤用户网的0.6μm CMOS激光驱动器

基于国内的CMOS技术和EDA工具以及全定制的设计方法,采用无锡华晶上华(CSMC-HJ)0.6μm CMOS技术实现了可工作于155Mb/s、622Mb/s的激光驱动器.该激光驱动器在50Ω负载上输出电流摆幅从0到50mA可调.在输出级3V直流偏置时最大输出电压摆幅可达2.5Vpp.输出电压脉冲的上升、下降时间分别小于471ps和444ps.四个工作速率下均方根抖动都小于30ps.电路在5V单电源供电时功耗小于410mW.芯片测试结果表明,该激光驱动器达到了世界同类集成电路的水平.     

A Fast-Speed Pulse Detector Based on N-Type Si-Schottky Diode via Tuning Circuit

A fast-speed pulse detector based on n-type Si-Sehottky diode mounted in the waveguide is investigated. The relation of the fast-speed pulse detector between response time and 3 dB bandwidth is analyzed. By adopting the tunable circuit, the matched bandwidth is achieved as wide as possible. Experi- mental results show that the pulse response time of the detector is less than 150 ps within random carrier signal 500 MHz bandwidth range between 35 GHz to 39 GHz via tuning circuit. The detector is very easy to operate because it does not need bias current or synch-pulse source.     

InGaAs/InP separated absorption and multiplication regions avalanche photodiode using liquid- and vapor-phase epitaxies

Heterostructure planar InGaAs/InP avalanche photodiodes, which consist of a vapor-phase epitaxial InP avalanche multiplying layer and a liquid-phase epitaxial In0.53Ga0.47As optical absorption layer, were fabricated. Dark current, multiplication, spectral response, and pulse response characteristics are reported. Diodes were prepared by InGaAs liquid-phase epitaxy on an InP substrate, followed by InP vapor-phase epitaxy. The vapor-phase epitaxy was adopted in the InP growth to avoid ternary layer melting encountered in the liquid-phase process. Cd diffusion was carried out in the InP layer to form a p-n junction. A uniform multiplication factor of 5.5 was observed without a guard ring. The quantum efficiency was 70 percent in the1-1.6 mum wavelength region without antireflection coating. Dark current density was as low as1.5 times 10^{-4}A/cm²at 90 percent of breakdown voltage. A fast rise time of 100 ps was observed.     

Ultrahigh-power picosecond current switching by a silicon sharpener based on successive breakdown of structures

Ultrafast current switching by a silicon sharpener based on successive breakdown of structures has been experimentally implemented and theoretically studied. A voltage pulse with an amplitude of 180 kV and a rise time of 400 ps was applied to a semiconductor device containing 44 series-connected diode structures positioned in a 50-Ω transmission line. After device switching, pulses with an amplitude of 150 kV and a rise time of 100 ps were obtained in the transmission line. Numerical simulation showed that the electric field near the p-n junction reaches the Zener breakdown threshold (∼10⁶ V/cm) at an input voltage rise rate of more than 4 × 10¹³ V/s per structure achieved in the experiment, even when the diode structure contains technological impurities with deep ionization levels and a concentration of 10¹¹ cm⁻³.     

New silicon epitaxial avalanche diode for single-photon timing atroom temperature

A new silicon single-photon avalanche diode (SPAD) with epitaxial structure is presented. The carrier diffusion effect, which has plagued the time response of previous SPADs, is strongly reduced. The resolution obtained, less than 30 ps full width at half-maximum, is the highest so far reported in single-photon timing     

A proposed punch-through microwave negative-resistance diode

A new microwave negative-resistance diode is proposed. The diode is similar to the Read diode insofar as the negative resistance is partially due to the finite transit time of carriers flowing through a depletion region. Unlike the Read diode, however, the carriers are injected into the depletion region by punch through rather than by avalanche. The resulting device is therefore expected to have a considerably better noise performance than the Read diode. The paper first explains qualitatively the punch-through operation of the proposed device and contrasts it with similar structures proposed earlier by Read and by Shockley. The large signal admittance of the punch-through diode is then obtained by using a sharp pulse approximation of the injection process. A device Q of -15 is calculated. Considering the device as a microwave oscillator, it is found that conversion efficiencies of the order of 20 percent should be possible. Estimates of the upper bounds on the microwave power are given. The paper concludes with a detailed account of design considerations for the device. Numerical designing examples for the frequency range of 1 to 5O GHz are given.