INTERFACIAL STRENGTH OF OPTICAL FIBRES

The interfacial strength of three different optical fibres were evaluated using a push-out test method. Polyimide coated optical fibres either without or with a silane sizing on the silica glass, and optical fibres with aluminium coating were tested. A significant increase in the interfacial strength was achieved with the silane sizing. The failure mode shifted from the silica glass/polyimide interface to the polyimide/composite. For the two other fibres the interfacial strength was similar. Pre-conditioning of samples with polyimide coated optical fibres indicates that moisture can result in a significant reduction in interfacial strength for fibres without sizing whereas the sizing has a protective effects on the interfaces to moisture.