OM3 and OM4 fibers are backward compatible. Connectors, transceivers, and equipment designed for one will generally work with the other, provided all components use the same core size (50/125 µm). However, the overall performance will be limited to the lowest-rated component in. Two of the most widely deployed laser-optimized multimode fibers are OM3 and OM4, both designed to support high-speed data transmission using VCSEL-based optical modules. However, despite their similar core size and compatibility, these two fiber standards differ in modal bandwidth, maximum. The OM4 fiber type was standardized in 2009, and compared to OM3 fiber, it has a higher modal bandwidth of 4700 MHz/km, while OM3 has a modal bandwidth of 2000 MHz/km. This means that OM4 can send more data than OM3 over the same distance. OM4 is best for 10G–100G, OM5 supports SWDM.
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