Optical loss stability of a fiber cable under lateral force and optimum design of the coated fiber structure.
Optical loss increase characteristics under lateral force were investigated to determine the load limit for coated fiber. Plastic deformation of the coating was analyzed, and the loss increase was found to occur in the large deformation region beyond a limit theoretically determined using structural dimensions (diameter and thickness) and the material constant of the coating. The optimum coating structure for preventing loss increase has been designed by introducing the result of the lateral deformation limit as well as fiber stress induced by the lateral force and fiber strain at low temperature. The nylon outer and silicone layer diameters are 0.9 and 0.4 mm, respectively.
Infrared loss increase phenomenon of coated optical fibers at high temperatures
The loss increase phenomenon of coated optical fibers at high temperature has been studied. The wavelength dependent loss increase, observed for plastic-coated fibers at 200°C, is found to be irreversible. During heating, the absorption peak of second overtone of Ge-OH preferentially appeared. The dependence of the loss increase on temperature, heating time, and dopant is also examined. The loss increase level is strongly dependent on phosphorous concentration. The experimental results indicate that the loss increase is caused by chemical reactions between fiber constituent materials and hydrogen generated from coating materials. It is also confirmed that the heating test of secondary coated fiber is a practical, useful method to evaluate the hydroxyl loss increase of optical fibers.
Anomalous Annealing Behavior of Arsenic Implanted Silicon as a Function of Dose and Energy
Anomalous annealing behavior of damage in As implanted Si has been investigated by channeling effect measurements. Room temperature As implants with doses from 1014 to 2 × 1016cm-2 at energies ranging from 50 to 250 keV into Si were annealed over the range of 600°C to 1100°C. Anneal temperatures ≥ 950°C reduce the disorder for ion doses of 0.5 to 1 × 1016 cm-2 at energies between 50 and 250 keV. Anomalously high residual disorder was found for the intermediate doses of 2 × 1014 to 2 × 10/cm2 implanted above 100 keV. For this intermediate dose, annealing of implants performed at liquid nitrogen temperatures did not show significant reduction in this damage. However implants at 200° to 300°C indicate a lower amount of damage compared to the room temperature implants.