For multimode fiber, the loss is about 3 dB per km for 850 nm sources, 1 dB per km for 1300 nm. 5 dB/km max per EIA/TIA 568) This roughly translates into a loss of 0. This is made possible by its relatively large core diameter, typically 50 or 62. 5 microns, compared to the ~9-micron core in single-mode fiber. Multi-mode fiber has a fairly large core diameter that enables multiple light modes to be. Multimode fibers are fibers having multiple guided modes at the operating wavelength — sometimes only a few (→ few-mode fibers), but often many. Figure 1: A single-mode fiber (left) has a core which is very small compared. ISO/IEC 11801 defines the OM1, OM2, OM3, OM4, and OM5 types of multimode fiber. In the two tables above, we've summarized the main differences between OM1, OM2, OM3, OM4, and OM5.
