Microbend test methods comparison

摘要

In recent years an increased interest for microbend sensitivity and testing is shown in various conferences. This is partly due to the new fiber category G.657, the bend-loss insensitivity fiber and partly to new coating systems, but also to other fiber studies. In IEC the technical report TR62221, microbend test methods, is being revised. The access network and in particular the FTTH part require smaller bends and therefore it is of interest to further elucidate the different techniques to evaluate microbend sensitivity. The IEC TR describes four different methods (A, B, C, D) to measure microbend sensitivity. The revised report will give more details about the different techniques and some experimental results for method B. However, no information is given about comparing the methods with each other. We have focused our study on method A and B. A short description of each technique will be followed by experimental results. Method A uses an expandable drum and Method B a fixed diameter drum. We will also briefly mention the content of method C and D. Since microbend testing using all four different methods is a huge task, we have concentrated our work on method A and B in the-present study. A justified question is whether one can draw the conclusion that these methods give the same qualitative answer, i.e. if method A indicates one fiber to be superior to another would that be the same if method B was used. We will show experimental results confirming that method A and B will give similar qualitative result.