System design methodology for power budgeting of 62.5 mu m multimode fiber systems

The authors present the data to support a recommendation of a new system loss budgeting rule applicable to high-component-count systems using 62.5 mu m core diameter multimode fiber. The limited phase space or restricted launch characterization of fiber is demonstrated again to give the most accurate system loss prediction. However, for this fiber size, components such as connectors, switches, and couplers are shown to exhibit loss equivalent to the overfilled launch loss. Two mechanisms are found to explain why the overfilled launch component loss best characterizes their actual loss in common multimode fiber systems. Both are related to the large numerical aperture (NA) of the power distribution launched by the light-emitting diode (LED) system sources. It is important to note that these mechanisms only have been observed on components made with 62.5 mu m multimode fiber. This behavior is likely to be different in other fiber sizes.<
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