OM3

OM3 is a grade of multimode optical fiber defined by international standards (such as ISO/IEC 11801 and IEC 60793-2) as a laser-optimized 50/125 micrometer fiber. It is designed to support higher-speed data transmission by using a graded-index core optimized for 850 nm vertical-cavity surface-emitting laser (VCSEL) sources. The defining performance characteristic is a minimum bandwidth-distance product of about 2000 MHz·km at 850 nm, which enables longer reach and higher data rates than older multimode fibers.

Typical applications include data-center and campus networks that deploy high-speed Ethernet and short-reach optical interconnects. In practice, OM3 can support 10 Gigabit Ethernet at distances up to roughly 300 meters, with 40/100 Gigabit Ethernet reaching shorter reaches (often around 100 meters) depending on the transceivers and link design. The fiber uses a 50 μm core with a 125 μm cladding and is compatible with common multimode connectors such as LC, SC, and high-density MPO/MTP assemblies.

OM3 is generally backward-compatible with other multimode fibers in the same family, though achieving the specified performance requires the appropriate transceivers and install practices. For context, a higher-performance variant, OM4, offers a larger bandwidth-distance product (around 4700 MHz·km) and extended reach for similar systems.