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Proposes a quasi-steady-state heat transfer/thermal stress model for dislocation generation in the vertical gradient freeze (VGF) growth of III-IV compounds. VGF growth model; Calculation of the temperature distribution; Factors influencing the generation of glide dislocations in III-IV compounds.

Provides information on a study that compared two avenues available to achieve low dislocation densities in gallium arsenide grown by the vertical gradient freeze and liquid-encapsulated Czochralski techniques. Solution for the heat conduction equation; Result of experiments; Origin of dislocations in regions free of thermal stresses.

We show that frozen-in viscoelasticity has a significant impact on the refractive index profile of optical fibers. Viscoelastic strains can be frozen into an optical fiber during draw, or by cooling down a drawn fiber from its fictive temperature while under tension. The resulting refractive index perturbation is concentrated in the highest viscosity region of the fiber, exhibits minimal birefringence, and can significantly alter critical performance characteristics. Our quantitative theory for the refractive index perturbation is in excellent agreement with measured data. Frozen-in viscoelasticity can also be harnessed to serve as the basis for optical fiber devices. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]