Described herein are initial experimental details and properties of a silicon core, silica glass-clad optical fiber fabricated using conventional optical fiber draw methods. Such semiconductor core fibers have potential to greatly influence the fields of nonlinear fiber optics, infrared and THz power delivery. More specifically, x-ray diffraction and Raman spectroscopy showed the core to be highly crystalline silicon. The measured propagation losses were 4.3 dB/m at 2.936 microm, which likely are caused by either microcracks in the core arising from the large thermal expansion mismatch with the cladding or to SiO(2) precipitates formed from oxygen dissolved in the silicon melt. Suggestions for enhancing the performance of these semiconductor core fibers are provided. Here we show that lengths of an optical fiber containing a highly crystalline semiconducting core can be produced using scalable fiber fabrication techniques.

The oxidation rate of SKI, was studied at 1100" to 1300°C. The reaction was first order in SiC1, and zero order in 0, up to a 20-fold excess of 0,. At higher 0, concentrations, the reaction becomes first order in oxygen. The activation energy for the reaction was 962 5 kcaVmol which is approximately the CI:,Si-CI bond energy. The reaction SiCl,+SiCI:,+CI is proposed as the rate-determining step.

The pyrolysis of -butane was studied in a tubular gold reactor at temperatures of 515-605°C, at atmospheric pressure, and mole fractions of butane between 0.01 and 0.9. Under these conditions the conversions of butane were 0.03-7.0%. It was found that the orders of reaction with respect to butane for the various products were not equal and ranged from 1.15 to 1.67. A mechanism, which includes explicit effects of primary and secondary butyl radicals as well as some possibly significant secondary reactions, is proposed which quantitatively explains the product ratios, orders of reaction, and activation energies. The mechanism shows that the role of secondary reactions is small at the low conversions used in this study.

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