OM4 is an enhanced version of OM3, using the same 50-micron laser-optimised core construction but manufactured to tighter tolerances that deliver a higher modal bandwidth of 4,700 MHz/km. That improved bandwidth translates directly into longer supported distances at the same speeds. In the complex landscape of fiber optic infrastructure, selecting the right cable type—single-mode (OS1/OS2) or multimode (OM1/OM2/OM3/OM4/OM5)—can define a network's speed, reach, and cost-effectiveness. This guide dissects their technical nuances, evolution, and real-world applications. While they developed the original "OM" designations, IEC has not yet released an approved equivalent. OM4 multimode fiber optic cables have a core diameter of 50 microns, which allows them to transmit data over distances of up to 550 meters at a speed of 40 gigabits per second (Gbps), and up to 150 meters at 100 gigabits per second (Gbps). These designations tell you everything about what a cable can actually do — how far it will run, what speeds it will support, and whether it's the right fit for your application.
Read More
