I am struggling with a concept and not finding much in the way of answers. The spec sheets for SFP+ 10 Gigbit Ethernet optics list the maximum cable distance as a funtion of the fiber type (MMF or SMF), Optical Wavelength, Core diameter and Modal Bandwidth. However, there are several distance entries for similar items that only differ in their modal bandwidth.
For example a SFP-10G-SR when connected to 62.5 micron MMF lists the maximum cable distance as either 26M or 33M depending on the modal bandwidth (either 160 or 200). Is there a way to figure out what the modal bandwidth of a given fiber strand is (short of performing a full fiber characterization study)? It seems that there is no relationship between the grade of MMF (OM1, 2, or 3) since 62.5 micron fiber should all be considered OM1.
This is becoming an issue since many companies are wanting to run 10Gigabit Ethernet over some incredibly old fiber plants, and I am trying to get an handle on which distance measures listed in the spec sheets are more realistic when they list multiple distances for the same fiber type that only differ in modal bandwidth.