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The effect of power/temperature step stress when applied to the zener diode JANTX1N3031B manufactured by Siemens and Motorola is reported. A total of 48 samples from each manufacturer was submitted to the process. In addition, two control sample units were maintained for verification of the electrical parametric testing.
The effect of power/temperature step stress when applied to the switching diode JANTX1N5618 manufactured by Semtech and Micro Semiconductor is reported. A total of 48 samples from each manufacturer was submitted to the process. In addition, two control sample units were maintained for verification of the electrical parametric testing.
The effect of power/temperature step stress when applied to a variety of voltage regulating diodes manufactured by Texas Instruments and Siemens was investigated. Test requirements are described and results are tabulated. Failure modes are discussed.
Data compiled for the purpose of evaluating the effect of power/temperature step stress when applied to the diode JANTX1N5420 manufactured by Unitrode and Micro-Semiconductor is presented. A total of 48 samples from each manufacturer was submitted to the processes outlined. In addition, two control sample units were maintained for verification of the electrical parametric testing.
Absolute intensities have been measured, using a diode laser spectrometer for several vibration-rotation lines in the nu4 fundamental of methane. The data have been analyzed, with the inclusion of Coriolis interactions, to obtain a transition moment of (0.0508 plus or minus 0.0015) x 10 to the minus 18th esu cm. This work appears to resolve some earlier difficulties in interpreting measurements and calculations of intensities in nu4 of CH4.
Measurements of mean and fluctuating axial velocity have for the first time been made in a seeded pipe flow with a semiconductor laser velocimeter. Several compact velocimeters have been constructed using laser diodes. While the intended applications have restricted the final instrument to operate in a coaxial backscatter mode, operation has been demonstrated in forward and side scattering modes. In all cases the instrument could be classed as dual beam. An instrument has been constructed to be installed in a model airfoil and will be mechanically driven to measure the flow over a 75-mm chord distance. The instrument occupies a volume measuring 100 mm x 100 mm x 40 mm. The compactness has been aided by using an avalanche photodiode instead of a photomultiplier tube.
Report describes effects of power and temperature overstress on Motorola and Siemens diodes. Failure was predominantly due to melted metal on die connections. Other failures are described.
The test results which were obtained with the HEPP liquid trap diode heat pipe prototype after it had been in storage for almost 27 months are presented. Transport data were obtained over the range of 150 to 220 K and reverse mode shutdown was measured with nominal operation at 180 K.
Several recent advances in the state-of-the-art of lead tin telluride double heterojunction laser diodes are summarized. Continuous Wave operation to 120 K and pulsed operation to 166 K with single, lowest order transverse mode emission to in excess of four times threshold at 80 K were achieved in buried stripe lasers fabricated by liquid phase epitaxy in the lattice-matched system, lead-tin telluride-lead telluride selenide. At the same time, liquid phase epitaxy was used to produce PbSnTe distributed feedback lasers with much broader continuous single mode tuning ranges than are available from Fabry-Perot lasers. The physics and philosophy behind these advances is as important as the structures and performance of the specific devices embodying the advances, particularly since structures are continually being evolved and the performance continues to be improved.
A breadboard heterodyne receiver is described which was used to establish the characteristics of lead salt diode lasers pertinent to their use as local oscillators using laser devices operating in the 15-25 micrometer spectral region. Heterodyne detection efficiency is directly correlated with the transverse mode structure and emphasizes the necessity of stable lowest order mode operation for lasers when used as local oscillators. The results obtained indicate that the continued development of these lasers provide suitable local oscillators for a variety of applications.
Initial operation of the tunable diode lasers (TDL) showed that it was not possible to adjust the wavenumber to one selected a priori in the TDL tuning range. During operation, the operating point would change by 0.1/cm over the longer term with even larger changes occurring during some thermal cycles. Most changes during thermal cycling required using lower temperatures and higher currents to reach the former wavenumber (when it could be reached). In many cases, an operating point could be selected by changing TDL current and temperature to give both the desired wavenumber and most of the power in a single mode. The selection procedure had to be used after each thermal cycling. Wavenumber nonlinearities of about 10% over a 0.5 cm tuning range were observed. Diagnostics of the single mode selected by a grating monochromator showed wavenumber fine structure under certain operating conditions. The characteristics due to the TDL environment included short term wavenumber stability, the instrument lineshape function, and intermediate term wavenumber stability.
A tunable diode laser heterodyne radiometer was developed for ground based measurements of atmospheric solar absorption spectra in the 9 to 12 micron spectral range. The performance and operating characteristics of this tunable infrared heterodyne radiometer (TIHR) is discussed along with recently measured heterodyne solar absorption spectra in the 10 to 11 micron spectral region.
A tunable diode laser heterodyne radiometer was developed for ground-based measurements of atmospheric solar absorption spectra in the 8 to 12 microns spectral range. The performance and operating characteristics of this Tunable Infrared Heterodyne Radiometer (TIHR) are discussed along with atmospheric solar absorption spectra of HNO3, O3, CO2, and H2O in the 9 to 11 microns spectral region.
High resolution spectra in the region of the v(2) band of nitric acid have been obtained for selected portions of the HNO3 spectrum using tunable diode laser techniques. Continuous spectra are presented from 1718.97/cm to 1729.57/cm, with a spectral resolution not greater than 0.001/cm (30 MHz). Absolute line intensities and line positions are presented. Self- and foreign-gas (N2) broadening coefficients were iteratively calculated from the experimental data and were determined to be alpha(a) = 0.74/cm atm and alpha (f) = 0.13/cm atm, respectively.
The paper deals with an approach which can improve the accuracy of etalon calibration of tunable diode-laser (TDL) spectra in the IR and extend absolute calibration among several isolated modes. Two etalons placed in the laser beam produce a combined fringe pattern that, with the aid of a monochromator mode selector, can be used to establish the number of fringes between any two spectral points separated by a large frequency interval. This technique has been applied to several similar cases for calibration of isolated modes or verification of the identity of lines of known frequency.
Performance results and design considerations are presented for an all solid-state Ku-band power amplifier which is feasible for use in PM communication systems for airborne or spacecraft transmitter applications. A six-stage GaAs FET preamplifier and a driver and balanced power amplifier utilizing GaAs IMPATT diodes operating in the injection locked oscillator mode are discussed. For high power and efficiency Schottky-Read IMPATT's with low-high-low doping profiles are employed. For improved reliability the IMPATT's incorporate a TiW barrier metallization to retard degradation of the IMPATT's. Results of accelerated life testing of the IMPATT devices are also presented.
Nuclear quadrupole hyperfine structure has been observed in the 1-0 vibration-rotation band of hydrogen iodide with a tunable-diode laser. The measured splittings agree well with microwave measurements of the HI molecule. Evidence for a slight change in the iodine nuclear quadrupole coupling constant from the ground to first excited vibrational state in hydrogen iodide was found.
Experimental results on postbreakdown bulk oscillations in n-type gold-doped phosphorus-compensated p(+)-i-n(+) double-injection diodes is presented. It is suggested that changes observed in the postbreakdown oscillation frequency and amplitude are due to changes in the prebreakdown characteristics. An empirical relationship for the frequency of oscillation is derived. It is concluded that the postbreakdown oscillations are drift-related, although their exact mechanism is not known.