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The human-body-model electrostatic discharge (ESO) testing is performed on various types of InP-based semiconductor lasers, fabey-perot (FP) and distributed feedback (DFB) lasers, in various regions of 1.3, 1.48 and 1.55 micrometers. The ESD damage is more accurately determined by the reverse voltage current (V-I) characteristics of the laser. The reverse VI exhibit lower laser ESD failure voltages than the forward polarity. The DFB lasers are more vulnerable to the ESD than to the FP lasers. Localized meeting, a thermal effect, caused the breakdown in the mechanism. The permanent aging rates of semiconductor lasers and the ESD effects on aging are also studied.

We report a new type of normalization procedure for modulation spectroscopy experiments in order to obtain the relative change in the reflectance (transmittance) spectrum ΔR/R(ΔT/T). Our new technique utilizes a servomechanism driven variable neutral density filter which keeps the dc component of the signal from the detector constant by varying the intensity of the light striking the sample. This method is particularly useful for photoreflectance measurements which can have background problems due to scattered pump light and/or photoluminescence. Advantages for other modulation spectroscopies, particularly in the region of the fundamental band gap of semiconductors, also will be discussed. [ABSTRACT FROM AUTHOR]

We have observed In out diffusion from strained In[sub x]Ga[sub 1-x]As quantum wells into the adjacent GaAs barriers in degraded 980-nm-wavelength strained quantum-well lasers. A previous calculation on misfit stress-induced compositional instability indicates that this material system is stable with respect to misfit strain. Therefore, the out diffusion of In from an In[sub x]Ga[sub 1-x]As quantum well is mainly driven by the compositional discontinuity across the well/barrier heterointerfaces, and is believed to be activated by the nonradiative recombination of injected carriers. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Using photoreflectance at room temperature we have evaluated the topographical variations in quantum level transitions of a GaAs/GaAlAs multiple quantum well (220 Å/150 Å) due to changes in barrier height and quantum well width. The spatial resolution of the measurement was about 100 μm. A key feature of our analysis is the ability to fit the electromodulation spectra by a third-derivative functional form line shape factor. We can detect barrier height changes of several millielectron volts and variations in well width as small as 2 Å. [ABSTRACT FROM AUTHOR]

The photoreflectance (PR) spectra of several GaAs/AlAs superlattices have been measured at 300 and 77 K using monochromatic light sources (laser or monochromator) as a secondary (pump) beam, thus enabling us to study the wavelength dependence of the PR. We demonstrate for the first time that electromodulation spectra from superlattices can be fit by a third derivative functional line shape, thus making it possible to precisely determine energies, broadening parameters, amplitudes, and phases of the spectral features. This result greatly enhances the usefulness of electromodulation to study and characterize these structures. The wavelength dependence of the PR shows that there is more than one PR mechanism in superlattices, in contrast to bulk material. [ABSTRACT FROM AUTHOR]

The changes in the polarization of the emission, spectrum, and light-current (L-I) behavior of a 1.3 and 1.5 μm InGaAsP channeled substrate buried heterostructure laser and double-channel planar buried heterostructure laser under an external uniaxial compressive stress perpendicular to the junction were studied at room temperature. It was found that the TM emission (electric vector perpendicular to the junction) reached threshold even at a stress level of ∼1×108 dyn cm-2. For stress ≤4×108 dyn cm-2, the TM emission, although reaching threshold first, was found to exist only over a limited range of currents. At high currents only TE emission (electric vector parallel to the junction) was observed. The appearance of the TE emission gave rise to nonlinear L-I characteristics. When both TM and TE emissions were seen, the former occurred at a higher energy. The limited stability of TM emission with current at low stresses is explained by invoking spectral hole burning effects which reduce the gain saturation power for TM mode than the TE mode. At high stresses ≥4×108 dyn cm-2, the increased gain for TM-polarized light ensures its stability at all currents. From our results it can be concluded that to avoid TM emission, and the associated spectral changes and nonlinear L-I characteristics, the tensile stress in the plane of the active layer should be less than 108 dyn cm-2. [ABSTRACT FROM AUTHOR]

The photoluminescence linewidth (4 K) of Al0.48In0.52As was reduced to 15 meV and its dependence was determined to be a strong function of the substrate temperature and As4 overpressure. Raman spectroscopy correlates the luminescence broadening to the crystallinity of the AlInAs. The ratio of the allowed longitudinal optical phonon to forbidden transverse optical phonon Raman peak heights is 10:1. [ABSTRACT FROM AUTHOR]

Explains a correction over the misplacement of the acronym IOD in the penultimate paragraph of the article 'Generic degradation mechanism for 980 nm in[sub x]Ga[sub 1]-[sub x]As/GaAs strained quantum-well lasers' published in the September 2001 issue of the journal 'Applied Physics Letters.'