OM4

OM4 is a designation for a grade of multimode optical fiber used in short- to medium-distance data networks. It is part of the Optical Multimode (OM) family (OM1, OM2, OM3, OM4, and OM5) and is defined by IEC 60793-2-50 and related standards such as ISO/IEC 11801 and TIA-568. The OM4 designation indicates enhanced performance over older multimode grades.

Like other OM grades, OM4 uses a 50/125 micrometer core/cladding geometry and is laser-optimized to improve coupling and bandwidth for 850 nm and 1300 nm wavelengths. It is designed for use with VCSEL-based transmitters and short-reach dense optical networks.

Compared with OM3, OM4 provides higher modal bandwidth, enabling longer link lengths at high data rates and improved tolerance to transmission penalties in data-center environments. It is commonly chosen for new installations where future-proofing for 40/100 Gb/s and higher Ethernet and storage networks is desired. It remains backward compatible with OM3 fibers and standard multimode connectors such as LC or SC.

In practice, OM4 is widely employed in data centers for campus backbones, and in enterprise networks that require scalable, high-speed multimode links. It supports standard, passive optical cabling and meets prevailing industry testing and performance metrics defined by the relevant standards bodies.