Abstract

Photoconductivity and photodielectric measurements of preforms and optical fibers have been performed. The measurements were done by using a noncontact microwave resonator technique. The photoinduced conductivity was measured to be 4 × 10^–7 Ω^–1 cm4 by using UV illumination at either 250 nm or 300 nm. In addition, a photodielectric shift of 500 kHz was measured. This shift amounts to an increase in the refractive index and indicates that there are shallow (~1–10 meV) polarizable traps just below the conduction band of the glass.

© 1992 Optical Society of America