Optical Fiber Interconnect Subjected to the Ends Offset and Axial Loading: What could be done to reduce the tensile stress in the fiber?

We examine an optical fiber interconnect subjected to the ends offset and subsequent thermally induced axial tension or compression. The objective of the study is to develop simple analytical ("mathematical") models for the prediction of the maximum tensile stress in the fiber. We use these models to find out what could possible be done to reduce this stress. We shoe that, it the ends offset is significant, the reactive tension (which occurs because the interconnect's supports cannot move closer, when the fiber bends) and the subsequent active (external) tension (which could be due to the thermal expansion mismatch of the glass and the material of the enclosure) not only lead to elevated tensile stresses in the fiber, but, more importantly, can result in a considerable increase int he bending stress. In order to minimize the tensile stress in the fiber, the ends offset and the active tension should be reduced. In the case of the subsequent compressive loading, however, there is a way to reduce the tensile stress substantially and, if the offset is not very large, even remove it al all. This could be done by a proper selection of the coefficient of thermal expansion (contraction) of the material of the enclosure. Based on the analysis, using the developed model, we suggest that this coefficient be chosen in such a way that the induced compressive force in the fiber, is about 44% of the critical value., a 34% relief in the bending stress can be achieved in such a situation (compared to the case of zero compression). Larger compressive force is not advisable, because of the rapid increase in the fiber curvatures (bending stress) and, as a result of that, in the total maximum tensile stress as well.