Excess noise of an Er/Yb fiber superfluorescent radiation source

A study is made of the noise in the output intensity of a high-power superfluorescent fiber radiation source generating 20 mW in the 1.55 μm region of the spectrum. The source is constructed in an all-fiber technology from a quartz fiber activated with ytterbium and erbium. It is found that the spectral density of the noise in the frequency range 100–500 kHz is uniform and corresponds to the excess noise of “thermal” sources. It is shown that the noise in the output intensity of the source can be compensated (decreased by an order of magnitude) in a two-channel scheme of photodetection, where it approaches a level close to the photon shot noise. Pis’ma Zh. Tekh. Fiz. 23, 1–6 (December 12, 1997)     

Concerning the question about physical model of birefringent spun fiber

An experiment have been proposed, proved and realized which help to make a choice between two models of evolution of light radiation polarization in optical fibers which are made by spinning highly linearly birefringent preforms during the drawing process (common term spun fiber). The model of helical structure of axes of built-in linear birefringence and the model which include circular birefringence are opposed. It is showed that polarization state evolution in spun fibers is described by the model of helical structure of axes of built-in linear birefringence. The article is published in the original.     

A New, 13C-Based Material for Neutron Targets

A ¹³C-based neutron-target material is investigated using x-ray diffraction, IR absorption and Raman scattering spectroscopies, transmission electron microscopy, and electrical (conductivity, magnetoresistance, and Hall effect) measurements before and after high-power electron irradiation for various lengths of time.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 5, 2005, pp. 531–539.Original Russian Text Copyright © 2005 by Romanenko, Anikeeva, Gorbachev, Zhmurikov, Gubin, Logachev, Avilov, Tsybulya, Kryukova, Burgina, Tecchio.     

Structure and Wear Resistance of Plasma-Sprayed NiCrBSiC–TiCrC Composite Powder Coatings

Powder Metallurgy and Metal Ceramics - The NTC20 and NTC40 composite powders were produced by conglomeration from the NiCrBSiC self-fluxing alloy with additions of 20 and 40 wt.% TiCrC,...