OM3 is a 50um core diameter multimode fiber optimized by 850nm laser. In 10Gb/s Ethernet using 850nmVCSEL, the fiber transmission distance can reach 300m; OM4 is an upgraded version of OM3, OM4 multimode fiber optimizes the OM3 multimode fiber Due to the differential mode delay (DMD) generated during high-speed transmission, the transmission distance has been greatly improved, and the optical fiber transmission distance can reach 550m.

The key difference between them is that under 4700MHz-km, the EMB of OM4 fiberis only specified as 850 nm, while the OM5 EMB value is specified as 850 nm and953 nm, and the value at 850 nm is greater than OM4. Therefore, OM5 fiber provides users with longer distances and more fiber options. In addition, TIA has designated lime green as the official cable jacket color for OM5.OM4 is designed for 10Gb/s, 40Gb/s and 100Gb/s transmission, but OM5is designed for 40Gb/s and 100Gb/s transmission, which can reduce the number ofoptical fibers for high-speed transmission.