Multimode fiber types include OM1, OM2, OM3, OM4, and OM5, each differing in core size, bandwidth, transmission distance, optical source, and typical applications.

Overview of Multimode Fiber

Multimode fiber (MMF) is designed for short- to medium-range communication, typically within buildings or campuses. It has a larger core diameter (50–62.5 µm) that allows multiple light modes to propagate simultaneously, making it ideal for high-speed LAN and data center applications. MMF is generally paired with lower-cost optical transceivers like LEDs or VCSELs and supports data rates up to 10 Gbit/s over distances up to 550 meters, depending on the fiber type .

Multimode Fiber Types

Key Differences

• Core Size: OM1 has a larger 62.5 µm core, while OM2–OM5 have 50 µm cores, allowing higher bandwidth and longer distances.
• Optical Source: OM1 and OM2 use LEDs, limiting speed and distance. OM3–OM5 are laser-optimized (VCSEL or SWDM), enabling higher-speed transmission.
• Bandwidth and Distance: Each successive OM type increases modal bandwidth and maximum transmission distance at high data rates. OM4 and OM5 are optimized for modern 40G/100G networks.
• Jacket Color: OM1/OM2 are orange, OM3/OM4 are aqua, and OM5 is lime green to indicate wideband capability.
• Applications: OM1/OM2 are mostly legacy networks, OM3/OM4 are standard for current enterprise and data center deployments, and OM5 is designed for future high-bandwidth, multi-wavelength applications.

Summary

Choosing the right multimode fiber depends on network speed requirements, distance, and future scalability. For modern high-speed data centers, OM3 or OM4 is typically recommended, while OM5 is suitable for next-generation networks requiring multiple wavelength channels. Legacy installations may still use OM1 or OM2, but these are generally considered obsolete for 10G+ applications .