bluuebunny/crossref_metadata_2025 huggingface dataset:
Photon Counting with Silicon Avalanche Photodiodes
Authors: Dautet Henri , Deschamps Pierre , MacGregor Andrew , McIntyre Robert , Trottier Claude
Published: February 2023

Within the past few years, avalanche photodiodes (APDs) have been developed with detection efficiencies for single photons as high as 50% and dark count rates in the 104 cps range at room temperature. Besides being extremely small and rugged, these devices have rapid recovery from overloads, wide dynamic ranges, very low after-pulsing, relatively low operating voltages (~200-400V) compared to PMTs, and other properties which make them very suitable for use in photon correlation systems. The purpose of this paper is to review their properties when used in the photon counting mode, to summarize recent progress, and to indicate the types of further improvements that should be possible in the future.
Hardware and Software Modification of a Commercial Laser Vibrometer for Investigation of High Amplitude Surface Fluctuations with Optical Tracking
Authors: Cheung H. Michael , Meyer William V. , Taylor Thomas W. , Tin Padetha , Barmatz M. , Biswas Abhijit , Mann J. A.
Published: February 2023

We have designed, implemented and tested a way of measuring the power spectrum of high amplitude surface fluctuations. A commercial laser vibrometer from Polytec, PI was modified with custom optics and software for this application. The instrument has been tested on levitated drops, levitated bubbles, and on driven fluid surfaces. Independent theory predicted the change in spacing of the fundamental driving frequency and its observed harmonics and subharmonic as the amplitude of the surface waves increases and the system becomes chaotic and turbulent. We observed these predictions along with the appropriate power spectrum for the driving frequency or frequencies and the related harmonics.
Particle Sizing from Spectral Extinction Data
Authors: Ferri Fabio , Paganini Enrico , De Stefano Luca
Published: February 2023

Particle sizing is a topic of great interest for the characterization of many biological, chemical and physical systems. Among the techniques which deal with particle sizing, the optical methods and, in particular the scattering techniques, are the most suitable and convenient ones. Indeed, they allow the characterization of a large number of particles to be carried out in situ and in real time. Scattering techniques include dynamic light scattering for studying submicron particles, low angle elastic light scattering for particles larger than microns, and spectral extinction methods for particles of intermediate size. This last method is probably the most convenient one since it requires a very simple optical layout, obtainable, for example, by adapting commercial spectrophotometers.
Discrete Wavelet Analysis as a Tool in Dynamic Light Scattering
Authors: Kroon Mark , Wegdam Gerard H. , Sprik Rudolf
Published: February 2023

In dynamic light scattering the intensity correlation function is calculated by means of a correlator from the measured scattered fluctuating intensity. Subsequently the intermediate scattering function, or its Fourier transform the dynamic structure factor, can be extracted from the correlation function. This by now classical method has, as any experimental technique, its own limitations. One of the limitations becomes apparent when the intensity correlation function possesses an algebraic tail. It is observed for example in colloidal or polymeric systems undergoing a glass transition1-3. Then it is possible, but difficult to extract the true intermediate scattering function of the system, even though the system is considered in equilibrium. Non-stationary systems or systems behaving chaotically in time pose a real problem. For a non-stationary system the zero frequency divergence in the power spectrum of the fluctuating intensity precludes any quantitative analysis by means of correlation functions, since an infinite time range should be covered. Examples are the formation of a glass or a gel, and turbulence.
Nucleation and Growth of Amyloid β-Protein Fibrils: Detection of Nuclei and Quantitation of Rate Constants
Authors: Lomakin Aleksey , Teplow David B. , Kirschner Daniel A. , Benedek George B.
Published: February 2023

Alzheimer's disease is a progressive, neurodegenerative disorder characterized by amyloid deposition in senile plaques in the cerebral parenchyma and vasculature.(1) These plaques are composed primarily of fibers of the amyloid β-protein, Aβ. A number of studies have provided information on the structure of fibrils formed both in vivo and in vitro, and on factors affecting fiber formation. Synthetic Aβ peptides also form fibers which are ultrastructurally indistinguishable from those isolated from the brain. These peptides have been utilized to examine how a variety of parameters, including temperature, pH, solvent composition, peptide concentration, and peptide sequence, influence the final structure of Aβ aggregates. What is substantially less understood, however, is the kinetics of Aβ fibril growth.
Nonlinear Effects in a Self-Q-Switched Ytterbium Doped Silica Fiber Laser
Authors: Chernikov S. V. , Taylor J. R. , Gapontsev V. P.
Published: February 2023

Fiber lasers and amplifiers have a great potential for many applications in different areas of technology. Various configurations of CW , mode-locked , Q-switched or single-frequency lasers have been reported offering a large variety in performance characteristics. Apart from the use of active fibers as the gain media in the traditional configurations based on concepts developed for bulk lasers, it has appeared that the unique and rather special properties of fiber lasers, like the high single pass gain and in particular numerous nonlinear effects in optical fiber waveguides, have yet to be exploited in novel configurations of fiber lasers.
New Polarimetric Scatterometer for Mueller Matrice Real Time Analysis of Rough Surfaces and Particle Suspensions
Authors: Delplancke Françoise
Published: February 2023

Static scalar light scattering1,2 has, since long ago, proved to be very interesting and useful in many theoretical and practical fields, related to surface and particle suspension investigation. Vectorial approaches provide even more information on the sample characteristics. While most of the theories assume spherical particles, spheroids or gaussian random surfaces with low slopes, real samples do not satisfy in general those assumptions. Scalar (i.e. intensity) measurements are unable to detect this non-ideality. So the predicted values of particle or roughness size are biased. On the contrary, vectorial (i.e. polarization) measurements 3,4,5,6 can provide ways to detect, identify and evaluate the shift from ideality (non spherical particules, porosity, high slopes...).
Recent Developments in Laser Light Scattering
Authors: Canned David S.
Published: February 2023

If so inclined, one might trace photoelectric mixing back to at least 1883, when Righi [1] demonstrated experimentally that a beam of light, split into two beams and frequency shifted relative to each other produced moving fringes when recombined, which he interpreted as beating. By 1947 Forrester, Parkins and Gerjuoy [2] had proposed that even light from two different, and thus completely incoherent, sources could be made to produce beats, and Gorelik [3] had pointed out that the output current from a fast photo-detector, when illuminated by a single spectral line should contain frequency components up to approximately the spectral linewidth. Forrester, Gudmundsen and Johnson [4] silenced all critics when they detected the beat note between two Zeeman components of the 5461 Å line of Mercury in 1955, and by 1959 Raman [5] had described a time-dependent speckle pattern observed by scattering light from a thin film of milk illuminated by a narrow beam of light from a Mercury arc lamp.
Surface Light Scattering: Integrated Technology and Signal Processing
Authors: Lading Lars , Earnshaw John
Published: February 2023

Surface light scattering has matured to the extent that it is now possible to envisage the possibility of applying the technique in more demanding environments like microgravity or industrial process monitoring. Such situations will require more compact and robust system designs than the ones that till now have been used in laboratory studies. The generic elements of a system are identified and their impact on system performance is given based on the model presented in.1 We note that proper use of a grating provides a calibration that is independent of the wavelength. This facilitates the use of cheap unstabilised semiconductor lasers2, but the optics may be rather delicate. An implementation with holographic optical elements gives a mechanically very simple and robust system (Fig. 1)3. A concept based on fully integrated optics is obtained by combining a 2D waveguide with diffractive structures for coupling light out of and into the optical “chip”. The waveguide would be combined with the lower hologram. Laser and detectors could be imbedded in the waveguide. Such a system implies a number of conflicting requirements of the integrated optics. A potential solution based on silicon and a rare earth laser is presented. The complexity of the system may be further reduced by the application of intracavity diffractive structures (Fig. 2). By doing this, we essentially eliminate the need for the very high diffraction efficiency required with external diffractive structures and the laser itself may also be used as a detector. However, the simple configuration requires a spacing to the surface that is fixed within a fraction of the optical wavelength.
Improved Analysis of Photon Correlation Data
Authors: McNeil-Watson F K
Published: February 2023

The emphasis in recent years on improvements in the polydisperse analysis problem - that is the recovery of accurate particle size distributions from PCS data, have concentrated on two areas. Firstly the measurement of the correlation points at a logarithmically spaced set of points, that effectively match the collection of data to the distribution of information in exponential functions. Secondly the use of fitting methods that apply constraints either implicitly or explicitly to the range of possible solutions that are evaluated in the fitting process.
Discrimination Techniques for a Highly Accurate Laser-Sheet Anemometer
Authors: Smart Anthony E. , Abbiss John B.
Published: February 2023

This paper discusses a laser anemometer based on projected light sheets and using a sequence of non-linear discrimination stages in both optics and electronics. Innovative digital correlation techniques yield significantly more accurate transit time measurements than can be obtained from equivalent fringe or two-spot systems. Enhancements of signal processing based upon a priori knowledge of the optical sheet definition and the measurement environment result in up to an order of magnitude increase in accuracy.
Photon Counting Silicon Avalanche Photodiodes for Photon Correlation Spectroscopy
Authors: Lightstone A. W. , McIntyre R. J.
Published: February 2023

Avalanche photodiodes can count photons either above the breakdown voltage or, with sensitive amplifiers, below the breakdown voltage. Detection efficiency, dark count and afterpulsing are discussed for the PCS application.
Resistive Anode Photomultiplier Tube Optimum Operating Conditions for Photon Correlation Experiments
Authors: Floryan R. F. , Johnson C. B.
Published: February 2023

One of the most important new photon-counting two-dimensional imaging detectors developed in the last few years is a microchannel plate photomultiplier tube having a resistive anode readout. Some of the details of the design and performance characteristics of this detector have been described by Firmani (3) and Rees (5). This type of imaging photon detector (IPD) has been used by Dainty, et al (6), to perform photon correlation experiments on dynamic speckle. An ITT version, #F4146M, of this IPD has been tested with a Surface Sciences Instruments model 2401 position computer. Limiting resolution, relative counting efficiency, and linearity have been measured under a variety of operational conditions, and optimum values have been determined. These conditions are presented and discussed in detail. The limiting spatial resolution varies from about 50 um FWHM at the center, to about 65 um FWHM near the edge of the IPD's 25 mm active diameter. The relative counting efficiency is found to be optimized for the same general operating conditions that produce the best spatial resolution, and the IPD and Surface Sciences Instruments position computer system is linear for count rates up to at least 1E4 cps.
Optimizing Fitting Statistics in Photon Correlation Spectroscopy
Authors: Shaumeyer J. N. , Gammon Robert W.
Published: February 2023

We have performed an experiment to test our understanding of the run time, T, necessary to achieve a specified precision in the value of the intensity coherence time, τc, extracted from correlation functions taken in the strong signal limit, and to test predictions for the values of some experimental parameters that optimize the precision. Using ensembles of 10 correlation functions taken at 5 different choices of sample time, we found that the ensemble estimators for the error in τc were well described by the expression
δτ/τ
c
=4.2/T/τ
c
, in agreement with the work of Degiorgio and Lastovka (1971). The sample times used were chosen so that the number of coherence times spanned by the 128 channels of the correlator, α, covered the range 1 ≤ α ≤ 16; in this range, we found no evidence of a minimum in δτ/τc to suggest an optimum value of α. These results were independent of whether we used three-parameter or two-parameter least-squares fits to extract τc. However, we did find that the two fits gave systematically different values of τc, and both show a similar dependence on α.
Analysis of Dynamic Light Scattering from Transient Gels
Authors: Nossal Ralph
Published: February 2023

The possibility of using dynamic light scattering to measure parameters describing the dynamic response of transiently bonded gels is investigated. When a sample is subjected to externally imposed mechanical excitation, a resonance in the frequency dependence of the response will be observed if the relaxation times for bond formation and breakage are long on a timescale determined by the dimensions and the instantaneous shear modulus of the sample. However, if the relaxation is fast on such a timescale, the response does not show resonance behavior and is maximal at zero frequency. Analytical expressions are provided that relate the half-widths of spectral response to kinetic parameters pertaining to the internal restructuring of the gel matrix.
Range Gating of Photons Multiply Scattered in a Stratified Ocean
Authors: Erdmann J. C. , Saint Clair J. M.
Published: February 2023

The applicability of digital correlators to LIDAR is investigated for the special case of a subsurface lidar probing optical depth of the water column in the ocean. The correlator is assumed to operate in the signal averaging mode. For generality a bi-static configuration is analyzed which has advantages under lowest light level conditions. Multiple scattering in the ocean is simulated by a Monte Carlo method. Analysis is included to derive the number density of photons arriving at the detector and the expected arrival time distribution in relation to the lidar pulse energy. Optical depth is obtained by logarithmic display of the correlator channel contents. It is concluded that actual experiments should be possible with existing fast digital correlators and pulsed dye lasers of 1 mJ pulse energy or less.
Heterojunction Bipolar Transistor Technology for High Speed Integrated Circuits
Authors: Asbeck P.M.
Published: February 2023

A bipolar structure provides many potential benefits for picosecond electronic circuits: (a) current flow is vertical, through epitaxial layers whose total thickness is only a few tenths of a micron, decreasing carrier transit times; (b) large amounts of current can be carried by modest size transistors, enabling rapid charging of interconnect capacitances; and (c) threshold voltages are tied to built-in potentials of p-n junctions, which are easy to reproduce device-to-device, enabling accurate logic voltages to be established. Added advantages result from using III-V heterojunctions rather than Si: (a) high electron mobility; (b) pronounced transient electron velocity overshoot effects; (c) ability to incorporate quasi-electric fields into the devices by semiconductor composition variations; and (d) ability to insure adequate emitter efficiency with wide gap emitters. As a result of these advantages, HBTs offer prospects for switching time delays in the sub 10 pS regime, with a robust, manufacturable fabrication process.
Picosecond Photoconductivity In Polycrystalline CdTe Films Prepared By UV Enhanced OMCVD
Authors: Johnson A. M. , Kisker D. W. , Simpson W. M.
Published: February 2023

Picosecond photocurrent transients have been reported in thin films of amorphous[1] and radiation-damaged[2] semiconductors. We report the first measurements of picosecond photoconductivity in 1800 A thick films of polycrystalline CdTe grown by organometallic chemical vapor deposition (OMCVD) with a grain size of approximately 200 Å. We have made high-speed photodetectors with a sampling oscilloscope limited response time of 35 psec (FWHM) with an average drift mobility of μ ≥ 11cm2/Vsec. The variation of the grain size as a means of varying the carrier relaxation time and drift mobility will be discussed.
High-Speed Internal Photoemission Detectors Enhanced by Grating Coupling to Surface Plasma Waves*
Authors: Brueck S. R. J. , Diadiuk V. , Jones T. , Lenth W.
Published: February 2023

The use of gratings to couple optical energy into surface plasma wave modes that are confined to a dielectric-metal interface has been extensively explored. We report on the first use of this coupling to enhance the quantum efficiency of internal photoemission detectors on III-V semiconductors. In this type of device, hot carriers are generated in a metal film by optical absorption and are collected by internal photoemission over a Schottky barrier into the semiconductor. For our initial experiments, the Au-(p-InP) system was used. Gratings, 25-100 nm deep, with a period of 2 μm and a line/space ratio of ~ 1/3 were fabricated photolithographically on heavily doped (~ 1 × 1018 cm−3) p-InP (see inset to Fig. 1). Au films, 25-100 nm thick, were evaporated to form the Schottky barriers; the device active area was 1.6 × 10−4 cm2.
Picosecond Electro-Electron Optic Oscilloscope
Authors: Williamson S. , Mourou G.
Published: February 2023

The technique of picosecond electro-optic sampling for time-resolving ultrafast electrical transients is presently the only means by which an electrical waveform can be measured with single picosecond resolution. In addition, the electro-optic sampling oscilloscope is capable of millivolt sensitivity and can be used in a contactless configuration, a feature that will enable the rapid characterization of packaged electronic circuits or 2-dimensionai mapping of electric fields. The major drawback of the electro-optic sampling oscilloscope is that it requires a short pulse laser system. The complexity of such a laser system results in a sampling oscilloscope that is delicate, maintenance intensive, and expensive, precluding its development in all but a few large laboratories.
A Study of Exciton and Carrier Dynamics and a Demonstration of One-Picosecond Optical NOR Gate Operation of a GaAs-AlGaAs Device
Authors: Peyghambarian N. , Gibbs H. M. , Jewell J. L. , Migus A. , Antonetti A. , Hulin D. , Mysyrowicz A.
Published: February 2023

We report the first time-resolved observation of a GaAs-AlGaAs multiple-quantum-well (MQW) optical NOR gate. The ≃ 1-ps speed of this room-temperature nonlinear etalon is the fastest for such a low-power optical logic device. About 100-fJ/μm2 energy per unit area was used for the logic operation.
22-GHz Bandwidth InGaAs/InP PIN Photodiodes
Authors: Bowers J. E. , Burrus C. A. , Tucker R. S.
Published: February 2023

Fast GaAs Schottky photodetectors for visible and near-infrared applications have been demonstrated [1], and high-speed PIN structures using InGaAs/InP for the emerging lightwave communications wavelengths (1.3–1.6 μm) have been reported [2,3]. We describe here the fabrication and characterization of an improved InGaAs/InP PIN photodiode with a measured 3 dB bandwidth of 22 GHz.
High-Speed Analog Signal Processing with Superconductive Circuits*
Authors: Ralston Richard W.
Published: February 2023

A new technology utilizing superconductive components for pulse compressors and convolvers that are capable of processing analog signals having bandwidths from 2-20 GHz will be described. The technology has two key features: low-loss and low-dispersion electromagnetic striplines which provide tapped delay on compact substrates; and superconductive tunnel junctions which provide efficient low-noise mixing and high-speed sampling circuits. A pulse expander/compressor pair (1) and a convolver (2) with respective time-bandwidth products of 86 and 21 have been demonstrated.
Picosecond Sampling With Josephson Junctions
Authors: Wolf Peter
Published: February 2023

A Josephson sampler basically consists of a sampling gate and a sampling-pulse generator. As Fig. 1 shows, the sampling gate is a Josephson junction to which the signal, the sampling pulse and a dc bias are coupled either directly, as in the figure, or via control lines. The dc bias is adjusted such that the sum of the three inputs just reaches the threshold of the gate, the switching of which is detected by an external voltage dector. The dc bias is adjusted automatically with an external feedback loop. If the sampling pulse is moved along the signal by means of a variable time delay, then the dc bias current as a function of the delay will yield a replica of the signal.
Molecular Beam Epitaxy Materials for High Speed Digital Heterostructure Devices
Authors: Miller D.L.
Published: February 2023

Molecular beam epitaxy (MBE) has made many important contributions to research and development of III-V compound semiconductor devices. For example, MBE has become the predominant technique of epitaxial material growth for digital heterostructure circuits employing heterojunction bipolar transistors (HBTs) and high electron mobility transistors (HEMTs). This has occurred despite the relatively high cost of MBE apparatus, and the reputation of MBE as an esoteric technology. Since high speed heterostructure devices appear to be moving rapidly toward the production line, it is important to consider the status of MBE in device research and development, and the future of MBE in the transition to production.
Hybrid Signal Processor for Wideband Radar*
Authors: Yao I. , Hauser E. M. , Bouman C. A. , Chiang A. M.
Published: February 2023

The signal processing task for radar systems with large instantaneous bandwidth and wide range coverage stresses the throughput rate of conventional digital processors. In this paper, a hybrid analog signal processor for wideband pulse-Doppler radar1 is described. It offers the potential of a compact, high-throughput processor. In the processor, three types of analog signal processing devices are incorporated. They are: (1) a surface-acoustic-wave (SAW) convolver2 to perform programmable pulse compression for radar signals with 200-MHz instantaneous bandwidth in order to provide target range information with 0.75-m resolution, (2) optoelectronic sample-and-hold (S/H) circuits3 to perform the range gating function and the buffering of the sampled data into the Doppler processor, and (3) charge-coupled-device (CCD) matrix-matrix-product (MMP) chips4 to perform Doppler Fourier analysis in order to provide target velocity information.
Pulse Waveform Standards for Electro-Optic Sampling
Authors: Lawton Robert A.
Published: February 2023

The maturing of the semiconductor industry has resulted in the need for faster methods for the measurement of pulse waveforms. The measurement requirements are fast outstripping the capability of integrated circuit testers. The fastest commercial sampling oscilloscope today has a step response transition duration (risetime) of 20 picoseconds. For the measurement of single transients, available time resolution is somewhat less. This time resolution is not adequate to support the measurement of the faster semiconductor devices being developed such as gallium arsenide logic gates whose switching times have been estimated to be 12 picoseconds (1). Measurement of such transitions requires a significant advance in measurement technology. A prime candidate for making the required quantum leap in time measurement resolution is the electro-optic sampler (2). This sampler has a demonstrated resolution of 0.4 picoseconds and theoretical resolution limit much shorter than that.
Picosecond Pulse Production in the Semiconductor Laser with A 100 GHZ Repetition Rate
Authors: McLean J. , Haas D. , Wurl J. , Gustafson T. K.
Published: February 2023

We present, the possibility of optical phase modulation of the semiconductor laser to produce mode locked pulses. By the external injection of two laser lines we show that it is possible to modulate the index of refraction of GaAs through χ(3) strongly enough to produce pulses in the 5 to 10 psec range. The main advantage of this technique is that repetition rates as high as 100 GHz should be possible.
Frequency Chirping in Pulse Modulated Gain and Real Index Guided Single Quantum Well Lasers
Authors: Larsson A. , Andersson P. , Yariv A.
Published: February 2023

Directly modulated semiconductor lasers exhibit a dynamic frequency shift (chirp) which limits the performance of fiber-optical systems using dispersive fibers. This chirp is due to a carrier induced change in the refractive index. Both theoretical [1] and experimental [2] investigations show that the change in refractive index of the guided mode varies linearly with the optical confinement factor.
Picosecond measurements of gain-switching in a semiconductor laser driven by ultrashort electrical pulses
Authors: Downey P. M. , Bowers J. E. , Tucker R. S. , Wiesenfeld J. M.
Published: February 2023

We report on the temporal profile of optical pulses emitted by a semiconductor laser when driven by 17 ps electrical pulses. These optical pulses are detected with subpicosecond resolution by optical up-conversion sampling[1,2]. The short duration of our electrical pulses distinguishes this work from previously published reports on gain- switching experiments. The short electrical pulses enable us to operate in a regime where the optical pulse widths are limited only by the laser, even when it is biased at threshold. We have investigated how the risetime, falltime, FWHM, amplitude and delay time of the gain-switched pulses vary with the semiconductor laser’s operating conditions (e.g. dc bias current, the width and amplitude of the driving pulse, and temperature).
Non Stationary Transport in MODFET’s and Heterojuction Devices
Authors: Hess K.
Published: February 2023

New horizons have opened up in semiconductor research with the possibility of "band gap engineering" and the combination of signal transport by photons as well as electrons in new forms of ultra thin III-V compound layers.
Development of 18 GHz GaAs Static Frequency Dividers and Their Evaluation by Electrooptic Sampling
Authors: Jensen J. F. , Weingarten K. J. , Bloom D. M.
Published: February 2023

Digital integrated circuits (ICs) operating at clock rates above 10 GHz will have a significant impact on the performance of digital systems in the next decade. We have successfully employed advanced design and fabrication techniques to raise the operational frequency of room temperature GaAs MESFET divider circuits to 18 GHz, which exceeds speeds achieved by any other technology at any temperature.
Picosecond Sampling of Integrated Circuits
Authors: Rodwell M.J.W. , Weingarten K.J. , Bloom D.M.
Published: February 2023

GaAs microwave integrated circuits are now being developed for operation at frequencies as high as 40 GHz, while GaAs digital IC’s have been demonstrated with ring-oscillator propagation delays of 5-10 ps, with gate delays of 50-100 ps for larger-scale circuits. Digital IC’s are currently tested only by indirect technique (multistage propagation delay or cycle times), while microwave circuits are tested only by external scattering parameter measurement; if the circuit does not perform to expectations, the cause is not easily identified. Electrooptic sampling, providing picosecond-resolution measurements of the voltages within the IC, permits more detailed circuit evaluation.
Picosecond Electrical Pulses for VLSI Electronics Characterization
Authors: Halbout J-M. , May P.G. , Ketchen M.B. , Li G.P. , Chi C.C. , Scheuermann M. , Smyth M.
Published: February 2023

Opto-electronics techniques allow us to take full advantage of the subpicosecond laser technology to generate and characterize picosecond electrical pulses. (1) These pulses have frequency components extending into the terahertz region and are ideally suited to the characterization of ultrafast transistors. Because of the intrinsic nonlinearities in the response of a fast switching transistor, it is most desirable to study the device directly in the time domain and to characterize it in an electrical environment as close as possible to its working environment. Furthermore, it is most urgent to characterize the very environment where these ultrafast signals are generated and must propagate, i.e. transmission lines with micron design rules fabricated on materials compatible with tomorrow’s semiconductor technology.
Enhanced Performance Ultrabroadband Distributed Amplifiers
Authors: Zdasiuk G. , Riaziat M. , LaRue R. , Yuen C. , Bandy S.
Published: February 2023

Distributed amplifiers have been used in recent years to achieve amplification over multi octave bandwidths extending to millimeter-wave frequencies [1]. The distributed (or traveling wave) amplifier topology has been especially suitable for monolithic integration using GaAs technology due to low sensitivity to component parameter variations and a relatively high active/passive component ratio. A major drawback of the approach has been the relatively low gain per stage (4-7 dB) and high current consumption. This paper describes the application of novel circuit approaches (such as cascode-connected FETs and coplanar waveguide transmission lines) and advanced devices such as high electron mobility transistors (HEMTs) to improve performance, simplify fabrication and achieve over 10 dB of single-stage gain over the 2-20 GHz band. This band is of significance for electronic countermeasures systems and microwave measurement applications.
Recent Developments in High-Tc Superconducting Films and Devices
Authors: Buhrman R. A.
Published: February 2023

The discovery of high temperature superconductivity (HTS) has created the opportunity for major extensions of current electron device applications of superconductivity, including opening up the possibility of integration of superconductivity with semiconductor devices. However, due to the difficult nature of the presently known HTS materials, the actual realization of this opportunity faces severe challenges. In this talk I will describe recent advances in, and current prospects for, the production of high quality, well-oriented HTS films with acceptable superconducting properties on technologically useful substrates, both insulating and semiconducting. Emphasis will be given to the discussion of new and improved techniques for the lower temperature growth and in-situ formation of the superconducting phase. The stability of current HTS materials will be discussed. I will also report on successful techniques for the formation of very low resistance contacts to HTS films and for the patterning of epitaxial films to micrometer, and possibly submicrometer, dimensions. The most recent results on the microwave and millimeter wave surface losses of high quality HTS material will be presented, as well as results on picosecond pulse propagation experiments on transmission lines formed from epitaxial HTS films.
Millimeter Wave AlInAs-GaInAs HEMTs
Authors: Mishra U.K.
Published: February 2023

This paper reports the work done at the Hughes Research Labs in the area of mm-wave AlInAs-GaInAs HEMTS.
Femtosecond Excitonic Electroabsorption Sampling
Authors: Knox W.H. , Henry J.E. , Tell B. , Li K.D. , Miller D.A.B. , Chemla D.S.
Published: February 2023

Optoelectronic sampling based on the Pockels' effect1 has become an important technique for the measurement of electrical signals with the highest time resolution, currently at 300 fs. We present first results obtained using a new technique for femtosecond electrical pulse measurement: excitonic electroabsorption sampling (EES). We have previously shown that excitons exhibit a femtosecond electroabsorption response, however the device which was used did not facilitate propagation studies over macroscopic distances2. In our new embodiment, a coplanar stripline is fabricated on a GaAs multiple quantum well mesa ridge structure (Fig. 1). We thus obtain optical modulation by parallel-field electroabsorption, which is due to lifetime broadening by field ionization of the excitons3. The detection sensitivity is about 1%/volt in a 10 micron structure. We etch the GaAs substrate down to a 1 micron AlGaAs stop-etch layer in a 1×2 mm area and leave the stripline free-standing on the 1 micron thick film, thus obtaining an extremely low dispersion structure to test the EES concept. We use an infrared dye laser which produces femtosecond pulses at a wavelength of 805 nm4 at 82 MHZ repetition rate. The exciton energy is temperature-tuned to the laser with a Peletier device, in this case operating at about 5 degrees above ambient temperature. At 300 fs pulsewidth the laser spectrum is already comparable to the exciton linewidth, and we expect that shorter pulses will provide reduced sensitivity relative to the DC response. We expect that time resolution of 100 fs or less may be possible with this technique. We note that electroabsorption is a purely electronic phenomenon, with no ionic lattice contribution such as that of LiTaO3.
Measurement of Gigahertz Waveforms and Propagation Delays in an InGaAs/InAlAs MODFET Using Phase-Space Absorption Quenching
Authors: Wiesenfeld J. M. , Heutmaker M. S. , Bar-Joseph I. , Chemla D. S. , Kuo J. M. , Chang T. Y. , Burrus C. A.
Published: February 2023

We use the phase-space absorption quenching (PAQ) effect as a high-speed optical probe of the carrier density in the channel of an InGaAs/InAlAs modulation-doped FET (MODFET). This effect is caused by the presence of carriers in the quantum well that forms the MODFET channel, which suppresses the optical absorption of the 10 - 20 ps probe pulses at wavelengths near the first subband edge due to Pauli exclusion. Because the technique probes the carrier density in the gate, it can determine the logic state of the MODFET. We combine the charge-sensitive PAQ technique with voltage-sensitive electrooptic sampling to study internal dynamics of the MODFET. A channel charging time of 11 ps and a gate to drain propagation delay of 15 ps are measured.
120-GHz Active Wafer Probes for Picosecond Device Measurement
Authors: Majidi-Ahy R. , Bloom D. M.
Published: February 2023

We have developed frequency-multiplier and harmonic mixer active wafer probes for picosecond device measurements to 120 GHz. All-electronic 100 GHz on-wafer frequency-response measurements have been demonstrated using these probes.
Picosecond, Spatially Resolved Optical Detection of Charge-Density Modulation in AlGaAs Lasers
Authors: Heinrich H. K.
Published: February 2023

This paper presents the first application of a modified confocal optical probing system to spatially-resolving picosecond charge-density modulation along the cavity of an AlGaAs semiconductor laser. The measurements show that the internal charge concentration overshoots and then clamps at the threshold level in response to an input current pulse. The amount of overshoot was found to be proportional to the current pulse amplitude, and appears to agree with previous theoretical analyses.
Ultrafast Nonlinearities in InGaAsP Diode Laser Amplifiers
Authors: Hall K. L. , Ippen E. P. , Mark J. , Eisenstein G.
Published: February 2023

Using femtosecond pulses at 1.5 µm we study ultrafast gain and loss nonlinearities in InGaAsP optical amplifiers. Sub-picosecond pump-probe dynamics are observed.
Subpicosecond Multiple Pulse Formation in Actively Mode-Locked Semiconductor Lasers
Authors: Morton P. A. , Helkey R. J. , Corzine S. W. , Bowers J. E.
Published: February 2023

Theoretical results for active mode locked semiconductor lasers explain the multiple pulse phenomena seen for all experimental results to date showing subpicosecond pulses. Dynamic detuning, due to gain saturation, causes multiple pulse output by moving the main pulse away from the peak in the gain waveform. This mechanism also limits the inherent pulse width achievable with a given modulation waveform.
Ultrafast All-Optical Multiplexing-Demultiplexing Techniques for Future Optical Communications
Authors: Saruwatari Masatoshi
Published: February 2023

This paper reviews the all-optical switching techniques, based on the Kerr effect in optical waveguides, which could be applied to time-division multi/demultiplexing of high-speed optical signals. Potential applications are suggested.
Fabrication of Resonant Tunneling Diodes for Switching Applications
Authors: Diamond S. K. , Ozbay E. , Rodwell M. J. W. , Bloom D. M. , Pao Y. C. , Wolak E. , Harris J. S.
Published: February 2023

Resonant tunneling diodes have been fabricated in a microwave compatible process. Current densities in excess of 105 A/cm2 were achieved. Scattering matrix parameter measurements were performed to validate the equivalent circuit model used. Pulse forming structures were fabricated on chip and rise times from 6-10 ps were obtained.
Improvement of Space Dependent Sensitivity and Absolute Voltage Measurement in Non-Contact Picosecond Electro-Optic Sampling
Authors: Takahashi H. , Aoshima S. , Tsuchiya Y.
Published: February 2023

While the need for measurement systems capable of characterizing ultrafast electrical signals has grown according to the increasing speed of electrical devices, Valdmanis et al. have, for the first time, achieved time-resolved ultrafast photo-detection with accuracy of less than 1ps by electro-optic sampling using a CPM dye laser1)2). Nowadays the electro-optic sampling method has opened a new area as a measurement method of ultrafast electrical signals3)-7).
75 GHz SiGe Heterojunction Bipolar Transistors: GaAs Performance in Si Technology?
Authors: Stork J.M.C. , Comfort J.H. , Patton G.L. , Crabbé E.F. , Meyerson B.S.
Published: February 2023

SiGe HBTs have demonstrated new device and circuit records, extending the speed of silicon bipolar devices closer to a regime dominated by GaAs and other compound semiconductor technologies. This paper gives a review of these results and our present understanding in order to address the potential merits of SiGe HBTs in relation to Si and III-V bipolar technology.
Generation of High Power Femtosecond Optical Pulses from a Semiconductor Diode Laser System
Authors: Delfyett P. J. , Florez L. , Stoffel N. , Gmitter T. , Andreadakis N. , Alphonse G. , Connolly J.
Published: February 2023

Compact and efficient sources of high repetition rate, high peak power ultrashort optical pulses are needed to replace the standard ultrashort optical pulse generation schemes due to their relatively large size and poor wall plug efficiency. In this talk, an external cavity mode locked semiconductor laser system which combines both active and passive mode locking techniques is described. This system produces optical pulses that are 0.46 psec in duration with over 70 watt of peak power. These optical pulses are both the shortest and most intense optical pulses ever generated from a semiconductor laser system.
Broadband Periodic Antennas for Detecting Picosecond Terahertz Radiation
Authors: Dykaar D.R. , Federici J.F. , Greene B.I. , Levi A.F.J. , Pfeiffer L.N. , West K. W. , Anzlowar M.
Published: February 2023

Recent results from several groups have convincingly demonstrated that picosecond terahertz (THz) light pulses are a useful tool for far-infrared spectroscopy. This paper reports on the design, fabrication and initial performance demonstration of two antennas specifically designed for broadband pulsed THz detection.
Electron Transport in Double Barrier Diodes Studied by Differential Absorption Spectroscopy
Authors: Woodward T. K. , Chemla D. S. , Bar-Joseph I. , Sivco D. L. , Cho A. Y.
Published: February 2023

Double barrier tunneling heterostructures are part of an emerging class of devices that rely on quantum-mechanical effects for their operation. A deeper understanding of these devices is possible when diagnostic methods that augment electrical measurements are employed. In our project, we have used differential absorption spectroscopy (DAS) to investigate the operation of the double barrier diode (DBD). This technique, whose experimental realization is detailed in Fig. 1, relies on measurements of normalized changes in optical transmission, ΔT/T = [T(V) - T(V
0
)]/T(V
0
) where T(x) is the transmission at voltage x, arising from electrical modulation imposed upon the device.[l,2] For small signals ΔT/T = lΔα, where Δα = α(V0)-α(V) is the change in absorption and I is the length over which the change occurs. Lock-in signal extraction allows the observation of ΔT/T signals as small as ~ 10−4, permitting observation of events on length scales ~ l0Å with low probe intensities (we use an incandescent lamp). DBD depletion and accumulation regions can be seen, as can signals originating in the QW. This signal can be calibrated to obtain the QW stored charge Q. Other workers have reported measurements of Q using photoluminescence,[3] excitation spectroscopy in conjunction with photoluminescence,[4] as well as methods involving magnetic fields.[5] Since we can use low light intensities and rely on optical absorption-a technique allowing absolute calibration-we believe DAS to be both a significantly more accurate[3] and a much less invasive method of determining Q. In addition, we can determine the energy distribution of the electrons stored inside the QW, without the confusion caused by creating large numbers of highly excited electron-hole pairs in the measurement process. All samples were grown by MBE on conducting InP substates and show profound negative differential resistance (NDR). Geometries are similar to that illustrated in Fig. 2, with variable barrier thicknesses.[1] The barrier material is In0.52Al0.48As, with QW and electrodes being In0.53Ga0.47As. Measurements were performed on 150 μm2 mesas at 10K.
Propagation of Picosecond Electrical Pulses in GaAs for Velocity-Matched Modulators
Authors: Chen Yi , Nees John , Williamson Steve
Published: February 2023

A traveling-wave electro-optic modulator fabricated from GaAs can, in principle, be fabricated having a modulation bandwidth exceeding 500 GHz. To approach such performance will require the elimination of not only velocity mismatch, which now limits the state-of-the-art to ~40 GHz,[1] but also modal dispersion of the microwave signal, radiation loss, free carrier absorption, and losses due to skin effect absorption.
New Scheme of Electrooptic Sampling by Probe Beam Polarization Modulation
Authors: Takahashi Ryo , Kamiya Takeshi
Published: February 2023

Electrooptic (EO) sampling is a powerful technique to characterize very-high speed electrical waveforms in the time domain and to examine waveforms internal to Integrated circuits[1-6].
Photonic Switching and Automatic Cross-Connect Systems
Authors: Nagel Jonathan A.
Published: February 2023

There will be an explosion of digital facilities as more and more lightwave systems are installed in the next few years. The size and complexity of junction offices where transmission facilities are interconnected will increase, and rearrangements will be more frequent than in the past. Because of these factors, wideband digital switches will replace manual cross-connects at junctions.
Introduction to Switching Networks
Authors: Beneš Václav E.
Published: February 2023

We present a broad tutorial description of connecting network concepts and structures, divided into three categories: combinatorial, probabilistic, and operational, each with suitable examples.

Among the combinatorial aspects we single out the semi-lattice of network states, notions of mismatch and overflow, group theory applications such as the reduction of states by symmetries, construction of nonblocking networks, and topological characterization of such network properties as rearrangeability and nonblocking.

The probabilistic ideas we cover are (i) modeling of network operation, (ii) definition of loss (probability of blocking), (iii) load-loss relationships. Finally, such operational issues as good routing choices and time-space swaps and shuffles (time-division and/or packet switching) are touched on.
A New Architecture for Large Integrated Optical Switch-arrays
Authors: Duthie P J , Wale M. J. , Bennion I
Published: February 2023

We propose a new reflective switch-array architecture, and describe process-tolerant waveguide-reflectors. Experimental results from a reduced 8×8 Ti:LiNbO3 switch-array are presented and used to derive practical maximum array sizes.
Overview of Electronic Switching Technologies for Digital Logic
Authors: Keyes Robert W.
Published: February 2023

Modern computation depends on the representation of information in digital form. “Digital” means that there are a discrete set of signal values. All contemporary electronic logic uses just two digits, binary representation of information. There are two recognizable signal values. A binary unit of information is known as a bit. It can be represented by the position of a switch of the familiar ON-OFF type. The state of the switch or the signal is also conveniently represented by a 0 or a 1.
Exciton-Enhanced Photonic Switching inGaAs–AlGaAs Fabry–Perot Resonators
Authors: Kowalsky W. , Hackbarth T. , Ebeling K. J.
Published: February 2023

Exciton enhanced photonic switching in GaAs-AlGaAs multiple quantum well (MQW) etalons integrated with quaterwave stacks is demonstrated. For logical AND operation an on-off-ratio of 10 : 1 is achieved at 1 mW control power. An inverting switching characteristic of 4 : 1 is obtained employing an anti-reflection multilayer.
Reduced Waveguide Intersection Losses for Large Tree-Structured Ti:LiNbO3 Switch Arrays
Authors: Murphy T. O. , Hernandez-Gil F. , Veselka J. J. , Korotky S. K.
Published: February 2023

We describe modifications to waveguide intersections used in integrated-optic switches that permit reduced excess loss. Using the Beam Propagation Method as a guide, we designed and fabricated geometries that have 50% lower loss.
Linear Torsion-Hinged Deformable Mirror Device for Optical Switching
Authors: Boysel R. Mark , McDonald T. Gus , Sampsell Jeffrey B.
Published: February 2023

In this paper we describe a deformable mirror device and discuss its system-dependent optical performance in two applications: optical crossbar switching and frequency excision.
InP-Based 4×4 Optical Switch Module and Its Application to ATM Switching
Authors: Inoue H. , Kato T. , Sasaki Y. , Ishida K. , Mizuishi K. , Amada E. , Kashimura S.
Published: February 2023

A module hosting a 4×4 polarization-independent optical-switch array with an original fiber attachment has been fabricated and tested, and its application to ATM switching is proposed.
Experiment on Photonic Wavelength-Division and Time-Division Hybrid Switching
Authors: Nishio M. , Suzuki S. , Shimosaka N. , Numai T. , Miyakawa T. , Fujiwara M. , Itoh M.
Published: February 2023

Fast wavelength tuning of a filter and a laser diode among 4 of the 8 wavelengths is confirmed. It shows eight-wavelength-division and four-time-division hybrid switching capability for 100-Mbps signals.