Abstract

Indentation by a Vicker’s diamond pyramid is used to introduce flaws of controlled residual strength into the surface of silica optical fibers. The indentation sites exhibit plastic deformation with an associated residual stress field. They are considered to be a good model for abrasion damage and also model the thermal stresses around an adhering particle on the fiber surface. The indentation technique is therefore used to investigate the behavior of very weak flaws whose strength is close to the proof-stress level. At high indentation loads radial cracks that severely degrade the strength are formed. At lower loads the subthreshold indentations do not have well-defined radial cracks and are correspondingly stronger.

© 1994 Optical Society of America