Mechanical and chemical damage of optical fiber polymer coating

Systematic measurements have been implemented on commercial optical silica fibers in which the polymer coating has been damaged, either chemically or mechanically. Dynamic fatigue has been studied using a two point bending bench at different stress rates. Small mechanical flaws, subsequently controlled by SEM observations, were created on the polymer coating surface using a micro-hardness indenter, without reaching the glass surface. Chemical damage was implemented by methylene chloride either as a gel or as a liquid. In this later case polymer could be removed just after a few minutes. Fiber strength was altered when polymer - silica interface was affected.