Intermateability of Bend Insensitive Multimode Fiber with Standard Multimode Fiber

This paper presents experimental results for the intermateability between standard multimode fiber (MMF) and bend-insensitive multimode fiber (BI-MMF). Due to differences in fiber numerical aperture (NA) and waveguide structure, the mixing of these fiber types within an optical channel link can result in an increase in insertion loss at connector interfaces. One contribution to this added loss is referred to as NA loss. To characterize the NA loss, we obtained fiber samples from three major fiber manufacturers to determine the nominal variability in NA. Based on far field measurement data, NA probability density functions were obtained for both MMF and BI-MMF fiber types which enabled us to select test fibers representative of typical NA variability. The NA loss was measured for key differences in NA mismatch as well as different launch conditions in order to quantify the potential impact on optical loss budgets in high-speed networks. A brief overview of fiber NA is given and our experimental results are tabulated and compared with theory. In addition to NA loss the bend performance for BI-MMF is presented and other loss contributions are discussed