Showing papers on "Photodiode published in 1984"

High‐speed optical modulation with GaAs/GaAlAs quantum wells in a p‐i‐n diode structure

Abstract: A new type of high‐speed optical modulator is proposed and demonstrated An electric field is applied perpendicular to GaAs/GaAlAs multiple quantum well layers using a ‘‘p‐i‐n’’ diode doping structure of 4‐μm total thickness The optical absorption edge, which is particularly abrupt because of exciton resonances, shifts to longer wavelengths with increasing field giving almost a factor of 2 reduction in transmission at 857 nm with an 8‐V reverse bias The shifts are ascribed to changes in carrier confinement energies in the wells The observed switching time of 28 ns is attributed to RC time constant and instrumental limitations only, and fundamental limits may be much faster

Optical Communication Systems

Abstract: Part 1 Elementary discussion of propagation in dielectric waveguides material dispersion total dispersion in multimode and monomode fibres attenuation mechanisms in optical fibres inelastic scattering and non-linear propagation effects system considerations electromagnetic wave propagation in step-index fibre wave and ray propagation in graded-index fibres single-mode fibres the fabrication of fibres, cables and passive components fibre parameters specification and measurement. Part 2 Sources and detectors basic semiconductor properties injection luminescence the design of LEDS for optical communication the basic principles of laser action semiconductor lasers semiconductor lasers for optical fibre communication systems semiconductor photodiode detectors avalanche photodiode detectors and photomultiplier tubes. Part 3 The receiver amplifier the regeneration of digital signals coherent systems unguided optical communication systems optical fibre communication systems.

Fourier transform spectrometer with a self-scanning photodiode array.

Abstract: A Fourier transform spectrometer with no mechanical moving parts is described. The interferogram is generated spatially by a triangle common-path interferometer and is detected by a self-scanning photodiode array. The spectrum is reconstructed by fast Fourier transform in a microcomputer system. Since no moving part is used and a common-path interferometer is employed for simple, stable, and easy alignment, this spectrometer may be built in a relatively small size and with moderate cost. The self-scanning photodiode array as a multichannel detector may lead this spectrometer to the application to time-resolved spectroscopy. The optical throughput is much larger than that of a multichannel dispersion-type spectrometer, because in the system neither a slit nor an aperture is necessary. The emission spectra of a low pressure mercury lamp and a LED are shown to demonstrate the system performance.

The pinned photodiode for an interline-transfer CCD image sensor

Abstract: A pinned photodiode has been developed for use in an interline-transfer CCD. This photoelement has excellent blue response and high charge capacity. Both modeling and experimental results will be presented, including process considerations necessary to avoid unwanted barriers at the diode/transfer-gate edge.

Correlating optical motion detector

Abstract: An optical mouse utilizing a linear array of photodiodes is provided with circuitry to correlate during each self-timed cycle a new image with a stored image from the previous cycle with the new image offset relative to the stored image one pixel (photodiode signal) to the right, one pixel to the left, and also with no offset. All three correlations are done at the same time in separate correlators. Decision as to motion to the right, to the left or no motion is made on the basis of maximum correlation output. The new image is not stored in a second store array for use during the next cycle until any motion is detected, but it is stored in a first store array during the cycle when half the precharged photodiodes discharge below a predetermined level in response to incident light. A new cycle is initiated by precharging the photodiodes when any decision of motion or no motion is made.

Pseudo‐quaternary GaInAsP semiconductors: A new Ga0.47In0.53As/InP graded gap superlattice and its applications to avalanche photodiodes

Abstract: We have demonstrated for the first time a pseudo‐quaternary GaInAsP semiconductor consisting of a graded gap Ga0.47In0.53As/InP superlattice. The average composition and the band gap of this structure are spatially varied by gradually changing the thicknesses of the InP and Ga0.47In0.53As layers between 5 and 55 A while keeping constant the period of the superlattice (=60 A). This new graded gap superlattice has been used to eliminate the interface pile‐up effect of holes in a ‘‘high‐low’’ InP/Ga0.47In0.53As avalanche photodiode, without requiring the growth of a separately lattice‐matched Ga1−xInxAs1−yPy layer. High‐speed operation at 1.7 Gb/s and λ=1.55 μm has been achieved. Pseudo‐quaternary semiconductors represent a new technique of growing GaInAsP and can conveniently replace conventional Ga1−xInxAs1−yPy alloys in a variety of device applications.

III-V compound semiconductor devices: Optical detectors

Abstract: This article presents a review of the historical developments in optical detectors and discusses the motivations for interest in III-V semiconductors for optical-detector applications. Early device work in both depletion-mode photodiodes and avalanche photodiodes in III-V semiconductors is covered as well as the improvements that have been made in avalanche photodiode structures through work in silicon. Also, the results of ionization coefficient measurements on III-V compounds are summarized. Finally, several examples of recent avalanche photodiodes that utlilize the unique properties of heterostructures are presented.

Single photon detection at 1.3 μm using a gated avalanche photodiode

Abstract: We have done experiments on the detection of single photons at a wavelength of 1.3 μm using a gated Ge avalanche photodiode pulse biased above breakdown. The influence of traps on the breakdown voltage was measured and the possibility of using such an ultrasensitive photodiode as a quantum limited detector for optical communications is discussed.

Monolithic integration of a metal—semiconductor—metal photodiode and a GaAs preamplifier

Abstract: A metal-semiconductor-metal (MSM) photodiode and a preamplifier have been monolithically integrated on a GaAs substrate by a very simple fabrication process. Measurements have shown that the constituent MSM photodiode has a sensitivity of 2.2 A/W and a -3-dB cutoff frequency of as high as 1 GHz. The present photodiode has been found to realize an extremely high photosensitivity of the monolithically integrated circuit, 26 mV/µW.

Grazing incidence time‐resolving spectrograph for magnetic fusion plasma diagnostics

Abstract: A time‐resolving grazing incidence spectrograph based on an image intensified photodiode array detector has been constructed and has demonstrated its utility as a fusion plasma diagnostic. The total wavelength coverage is 15–360 A with 0.7 A resolution (line profile FWHM); portions of this range may be observed during a single plasma discharge with a bandwidth of ∼40 A when the detector is centered at 40 A and ∼80 A with it centered at 200 A. Integration times from 5.4 to 13.1 ms are available when the entire photodiode array is read out; integration times as short as 1 ms can be obtained for a few lines of interest through the readout of selected photodiodes. The spectrograph has been radiometrically calibrated over the 60‐ to 360‐A range at the NBS SURF II electron storage ring and is currently in operation on the Princeton Large Torus (PLT) tokamak.

Interline CCD image sensor with an antiblooming structure

Abstract: A ⅔-in 384 (H) × 490 (V) element interline CCD image sensor with a new antiblooming structure was developed. Blooming was suppressed without sacrificing photosensitivity and dynamic range by means of a vertical overflow drain positioned under (rather than beside) a photodiode. For 10-percent vertical height illumination the smear signal was reduced to 0.05 percent of the illumination signal. Well-balanced performance, namely, large dynamic range (72 dB), low random noise (65 rms noise electrons per charge packet), high-contrast transfer functions for horizontal and vertical directions, and a spectral response similar to the luminous efficiency curve were obtained under moderate operating conditions.

Microwave integrated optical modulator

Abstract: A Ti‐diffused lithium niobate, traveling wave modulator has been fabricated and tested at microwave frequencies. A Mach–Zehnder interferometer optical configuration and a coplanar waveguide electrical transmission line are used. For a 4‐mm interaction length, the modulator has a 3‐dB bandwidth of 13 GHz and requires only 2 V to switch at λ=840 nm. The frequency response is measured directly using an ultrahigh speed photodiode, and the test setup therefore constitutes the highest bandwidth efficient electro‐optical transmission system ever reported.

Parallel‐recording systems for electron energy loss spectroscopy (EELS)

Abstract: The present report paper deals with the use of a photodiode array for recording electron energy loss spectra in a transmission electron microscope. Important properties of the array are outlined, together with a description of the circuitry needed for interfacing the output to a multichannel analyser. In the direct-exposure mode, the device can easily detect a single (80 or 100 keV) electron, allowing inner-shell energy losses between 200 eV and 2000 eV to be recorded in about 10 seconds. By signal averaging a large number of readouts, a dynamic range of at least 105 is possible. Irradiation damage to the array can be controlled by cooling the array and by various anealing procedures. Sensitivity and DQE are lower, but the dynamic range is higher in the indirect mode, where a fluorescent screen is used to convert the electrons into visible photons, which are then imaged onto the diodes. The choice of screen material and of optical coupling to the array are discussed. Several spectral artifacts are described, together with spectrum-processing techniques designed to remove them.

Scintillation Detection with Large-Area Reach-Through Avalanche Photodiodes

Abstract: Silicon avalanche photodiodes of the "reach-through" type have been used as scintillation detectors with device performance closely approaching that of PMT's. The device consists of a 6 × 6mm diode with a 5 × 5mm photosensitive area in a 6.7 × 6.7 × 2.0mm package which is suitable for mounting in an array. Typical characteristics at room temperature are: quantum efficiency ?50% at ?=415nm; surface dark current <200nA; bulk dark-current (before gain) <1nA; noise current (at optimum gain of 20 to 50) <1pA/Hz?; response time <5ns; capacitance ?21pF; biasing voltage ?200-400 Volts. When coupled to a NaI(Tl) scintillator (9 × 9 × 38mm) photo-peak resolutions (FWHM) for 662keV radiation of 10.4% at 21°C and 9.8% at 0°C were measured. The measured noise equivalent primary charge of one detector at a gain of 50 was 121 electrons (51 electrons rms) at room temperature. The significance of this new detector to high resolution imaging systems and detector arrays is discussed.

Monolithically integrated In0.53Ga0.47As-PIN/InP-MISFET photoreceiver

Abstract: In0.53Ga0.47As PIN photodiode and InP MISFET were monolithically integrated on an Fe-doped semi-insulating InP substrate. Photoreceiver sensitivities were measured at 100 Mbit/s NRZ pseudorandom signals.

Fabrication and characterization of GaAs Schottky barrier photodetectors for microwave fiber optic links

Abstract: High‐Speed GaAs Schottky barrier photodiodes have been fabricated and characterized. These detectors have 3‐dB bandwidths of 20 GHz and quantum efficiencies as high as 70%. The response of the detectors to light modulated at 1–18 GHz has been directly measured. Microwave modulated optical signals were obtained by using a LiNbO3 traveling wave modulator and by heterodyning two laser diodes.

Multi-element reachthrough avalanche photodiodes

Abstract: Two approaches to making multi-element arrays of p+-π-p-n+reachthrough avalanche photodiodes are reported. In the first approach a single common avalanche region (p-layer) for all elements is used, with the segmentation between elements being on the p+layer. This approach has the advantage of having zero dead space between adjacent elements, but is difficult to fabricate, and has a very narrow range of operation in which it is neither noisy due to injection nor suffers from poor element-to-element isolation. In a second approach, the p+contact is common and separate avalanche regions are used. The problem for this case is the width of the dead space between adjacent elements which, because of field-fringing effects, is considerably wider than the actual physical distance between elements. A self-aligning technique is described for fabricating arrays by the second approach and the technique demonstrated with a 25-element linear array on 300-µm centers. The measured dead space is in the 60-80 µm range, depending on the gain. The array can be used at an average gain of 100 or more, has excellent element-to-element isolation, and NEP's below 2 × 1015W/Hz1/2at 800-900 nm and below 10-14W/ Hz1/2over the whole spectral range from 400 to 1060 nm.

Monolithic optoelectronic integration of a GaAlAs laser, a field‐effect transistor, and a photodiode

Abstract: A low threshold buried heterostructure laser, a metal-semiconductor field-effect transistor, and a p-i-n photodiode have been integrated on a semi-insulating GaAs substrate. The circuit was operated as a rudimentary optical repeater. The gain bandwidth product of the repeater was measured to be 178 MHz.

An interline CCD image sensor with reduced image lag

Abstract: An undesirable image lag with a long time constant was found in the interline CCD image sensor having an n+-p-junction photodiode (PD). This paper clarifies the image lag mechanism and proposes a new photodiode structure having very little image lag. The image lag measurement method and the experimental results are also given. The experimental results quantitatively agree with the analytical model, in which signal electrons are assumed to be transferred from the PD to the vertical CCD as a small subthreshold current. To eliminate the image lag, a p+-n-p-structure PD with low donor concentration is proposed, in which all the signal electrons can be quickly transferred before the subthreshold condition begins. As a result, decay lag values for the first and the second fields were reduced to half and no decay lags were observed after the third field.

Electro-optical fluid detector

Abstract: An electro-optical circuit for detecting fluid in a translucent or a transparent duct or tube, this circuit including an AC activated light emitting diode (LED) for transmitting a narrow beam of light through the tube and a photo transistor detection, sub-circuit activated by the LED light beam, the power to the LED being adjusted to operate the photo transistor of the detection circuit in its unsaturated, active region of operation.

High-speed planar-structure Inp/InGaAsP/InGaAs avalanche photodiode grown by VPE

Abstract: Planar-structure InP/InGaAsP/InGaAs avalanche photo-diodes have been realised by using a VPE-growth technique and a Be+ implanted guard ring. Sensitivity measurement has been performed at 1.3 μm and 1.8 Gbit/s. The minimum average received level required for 10−9 BER was −31.3 dBm, which was 1.2 dB better than the value for the Ge-APD.

Impact ionization rates for electrons and holes in Al0.48In0.52As

Abstract: The first measurement of the impact ionization rates for electrons and holes in Al0.48In0.52As is reported. Photomultiplication measurements in pin avalanche photodiodes give α/β≊2.5–3.0 in the electric field range 3.3×105 V/cm≤F≤4.3×105 V/cm. This material can therefore be used to implement a potentially high‐performance, long‐wavelength avalanche photodiode, with separate absorption and multiplication regions and a high‐low electric field profile (HI‐LO SAM APD).

Photovoltaic relay switch

Abstract: A photovoltaic relay which includes a unique pull down circuit for rapidly turning off the relays field effect transistor(s). The pull down circuit discharges the gate-to-source capacitance of the relay's field effect transistors by turning on a thyristor by turning off a light-activated switch connected between the gate and the cathode terminals of the thyristor. In one integrated circuit embodiment, the light-activated switch is energized by the same light source which activates the photodiode stack which drives the relay. The presence of the pull down circuit does not effect the turn on time of the relay.

Induced junction (inversion layer) photodiode self-calibration.

Abstract: The potential of a newly available oxide-n+-p inversion layer silicon photodiode as a radiometric standard is discussed. Data are presented relating the quantum efficiency of these diodes as a function of oxide and reverse bias. The theory of a simple absolute reflectometer/detector device is described and in situ reflectance corrections for one of the diodes are determined to establish its absolute response. Radiant power measured with this diode, at ten wavelengths between 295 and 1014 nm, was then compared with that measured by reference to electrical substitution radiometry.

Some Near-IR Spectral Emission Characteristics of the Inductively Coupled Plasma:

Abstract: Several spectrochemical measurement systems have been used for the characterization of near-IR emission spectra from the inductively coupled plasma, with particular emphasis on the determination of sulphur. Background emission spectra of Ar and N2/Ar ICPs and the emission spectrum of dimethylsulphoxide (DMSO) are presented and the major emission lines of Ar, N, C, O and S are tabulated. These measurements and data cover the spectral region from about 3 μm to 0.7 μm and were obtained using a Fourier transform spectrometer. Detection limits for the determination of sulfur using a monochromator in combination with either a Si photodiode, a Si photodiode array or a PbS detector at the 0.922 and 1.046 μm lines are presented. The best detection limit (20 ppm) was obtained with the Si photodiode detector at the 0.922 μm line.

Planar InP/GaInAsP/GaInAs buried‐structure avalanche photodiode

Abstract: A new planar InP/GaInAsP/GaInAs buried‐structure avalanche photodiode, which has a buried active region and an n−‐InP guardring region, has been developed A useful guardring effect and a uniform multiplication are obtained in the multiplication range of up to 30 The diode shows a dark current of 10 nA at a bias of 90% of the breakdown voltage, a maximum avalanche gain of 50 under 13‐μm light irradiation, and a gain‐bandwidth product of about 16 GHz

Use of spatial time-division repetition rate multiplication of mode-locked laser pulses to generate microwave radiation from optoelectronic switches

Abstract: Multiplication of the pulse repetition rate of a mode‐locked laser beam using an all‐optical technique has been used to generate microwave radiation from an avalanche photodiode as well as from an optoelectronic switch.