Arlie G. Standlee

Attenuation at 10.6μm in loaded and unloaded polycrystalline KRS-5 fibers

Extruded polycrystalline KRS-5 fiber exhibits a large amount of residual strain. This strain, which results from the large forces applied in the extrusion process, is a major contribution to the total attenuation. To study the effect of strain on fiber loss, we have measured the total attenuation coefficient αT and the attenuation coefficient due to scattering, αS, as a function of stress applied along the fiber axis. The applied stress σ induces a change in the refractive index, which in turn leads to bulk scattering and excess fiber loss. We have found that αT ∼ σ2, which is in accord with an extension of a recent theory by Harrington and Sparks.

Aging effects in bulk and fiber TlBr‐TlI

A study of optical aging in bulk and extruded fibers of thallium bromo‐iodide (TlBr‐TlI) is presented. A variety of techniques including secondary ion mass spectrometry (SIMS), powder neutron and x‐ray diffraction, infrared spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy are used to probe the chemical and structural properties of both pristine and aged material. High concentration levels of a hydrogen bearing impurity have been detected by SIMS and neutron scattering in aged TlBr‐TlI, and have been shown to be localized in the surface layers of fibers as well as bulk samples. We present EPR evidence which indicates that the hydrogen bearing impurity is water.

Aging Effects In Extruded Polycrystalline Thallium Bromo-Iodide Fibers

Optical aging in bulk and extruded fibers of thallium bromo-iodide is discussed. In particular, changes in optical attenuation with age are correlated with the physical properties of the material.

Single-Crystal Infrared Fibers Fabricated By Traveling-Zone Melting

Single crystal fibers of thallium, silver and cuprous halides have been fabricated by passing polycrys-talline extruded fibers through a small submillimeter melt zone, converting them to single crystal fibers. The lowest loss measured in a single-crystal fiber was 6.6 dB/m at 10.6 μm for AgBr, 620 μm in diameter and 80 cm in length.