Nanosecond and picosecond pulse transmission in optical fibres

Abstract

The transmission light intensity dependences of different silica glass fibres have been experimentally studied when nanosecond pulse trains were incident. A pronounced 13-42% transmission increase was found in contrast to the picosecond pulse irradiation when a monotonic transmission decrease took place. The photoinduced transmission increase is explained in terms of photothermally increased numerical aperture, the photothermal lens effect, and the photoinduced saturation of a weak impurity absorption. The obtained results can be applied in high power applications of fibres such as WDM fibre communication systems.