Showing papers by "AT&T Labs published in 1986"
TL;DR: In this article, the effects of feedback on the spectra of 1.5-μm DFB lasers from feedback power ratios as low as -80 dB up to -8 dB were measured.
Abstract: We have measured the effects of feedback on the spectra of 1.5-μm DFB lasers from feedback power ratios as low as -80 dB up to -8 dB. Five distinct regimes of effects are observed with well defined transitions between them. The dependence of these effects on the distance to the reflection is also investigated.
729 citations
TL;DR: In this article, the electronic wavefunctions of small crystallites are discussed within the effective mass approximation, and luminescence is observed from trapped carriers that may be in localized surface states.
Abstract: Semiconductor crystallites of characteristic dimension \sim20-100 A can be made by precipitation in liquids and dielectrics. These crystallites have bulk-like internal lattices. The optical spectra show partially resolved discrete features that result from carrier spatial confinement in three dimensions. Spectral shifts of more than 1 eV are observed. The electronic wavefunctions of small crystallites are discussed within the effective mass approximation. The pattern of discrete hole states is qualitatively different in small crystallites than in slab superlattices. In small CdS crystallites, luminescence is observed from trapped carriers that may be in localized surface states. The recombination emission is strongly coupled to crystallite phonons.
429 citations
142 citations
TL;DR: In this article, measurements and calculations of interferometrically demodulated phase noise in an InGaAsP DFB laser were performed and the results led to a novel method of laser linewidth measurement.
Abstract: Measurements and calculations of interferometrically demodulated phase noise in an InGaAsP DFB laser are reported. The results led to a novel method of laser linewidth measurement. The effect of this noise on a DPSK coherent system is considered.
131 citations
32 citations
TL;DR: Ces corrections ne varient pas en V −1/2 comme le prevoit la theorie, mais sont beaucoup plus importantes que celles observees dans les echantillons en volume.
Abstract: We report the first systematic study of the corrections to the electron density of states of a 1D system, ultranarrow granular aluminum wires. These corrections do not have the ${\mathrm{V}}^{\mathrm{\ensuremath{-}}1/2}$ dependence predicted by theory, but are significantly larger than the corrections observed in corresponding bulk samples. At high magnetic fields, low temperatures, and very low voltages, we see evidence of a logarithmic gap in the density of states.
15 citations
TL;DR: In this paper, the authors compared beam-recrystallized Si-on-insulator (SOT) and GOI material systems to gain complementary understanding of the crystallization mechanism that would benefit both systems.
Abstract: Characteristics of beam-recrystallized Si-on-insulator (SOT) and Ge-on-insulator (GOI) material systems are compared for the first time to gain complementary understanding of the crystallization mechanism that would benefit both systems. In general, GOI has been found to behave quite differently from SOI. In SOI, Si yields sub-boundaries; in GOI, Ge generates twinned or faceted crystals. In GOI, too, sub-boundary-like features were observed, but only occasionally in the midst of twinned crystals. Also observed in GOI was the phenomenon of seeded crystallization breakdown, where defect-free crystals from the seed abruptly turn into defect-laced crystals at a certain distance from the seed. This phenomenon is highly characteristic in SOI, but has never been reported for GOI. These findings are compared and discussed in light of the traditional understanding of crystal growth.
5 citations
TL;DR: In this paper, the incorporation of atomic fluorine into flame synthesized silica boules has been investigated, and three different methods were used: (a) in a low temperature process, using XeF2 as the fluorinating agent prior to consolidation, (b) utilizing SiF4 or SF6 in the reagent gas mix during the combustion synthesis and soot deposition step and (c) in situ treatment with SF6 during the dehydration/ consolidation step at elevated temperatures.
Abstract: The incorporation of atomic fluorine into flame synthesized silica boules has been investigated. Soot boules were doped with fluorine using three different methods: (A) in a low temperature process, using XeF2 as the fluorinating agent prior to consolidation, (B) utilizing SiF4 or SF6 in the reagent gas mix during the combustion synthesis and soot deposition step and (C) in situ treatment with SF6 during the dehydration/ consolidation step at elevated temperatures. All three methods produced uniformly down-doped glass after consolidation, although the maximum fluorine incorporation and level of down-doping for each method followed A
4 citations
Patent•
29 Jan 1986TL;DR: In this article, a supported metal is formed by solvating a metallic salt such as nickel nitrate and applying it to a support medium, which is then heated in the presence of a reducing agent to produce elemental metal.
Abstract: Supported intermetallic compounds are produced by a two-step process. In the first step, a supported metal is formed, for example, by solvating a metallic salt such as nickel nitrate and applying it to a support medium. The treated support body is then heated in the presence of a reducing agent to produce elemental metal. The supported metal is then treated with a reactive organometallic or metal hydride compound to yield a supported intermetallic compound. For example, supported elemental nickel is treated with hexamethyldisilane to produce supported nickel silicide.
2 citations