For short- to medium-distance networks, OM3, OM4, or OM5 multimode fiber is generally recommended, while OM1 and OM2 are suitable only for legacy or low-speed applications.

Overview of Multimode Fiber Modes

Multimode fiber (MMF) supports multiple light modes and is ideal for short-distance communication, typically within buildings or campuses, with distances up to 550 meters at 10 Gbit/s . The main types of multimode fiber are OM1, OM2, OM3, OM4, and OM5, each differing in core size, bandwidth, and maximum transmission distance.

• OM1: 62.5 µm core, orange jacket, LED light source, supports 10 Gbit/s up to 33 meters, commonly used for 100 Mbit/s networks .
• OM2: 50 µm core, orange jacket, LED light source, supports 10 Gbit/s up to 82 meters, suitable for 1 Gbit/s applications .
• OM3: 50 µm core, aqua jacket, laser-optimized for 850 nm VCSELs, supports 10 Gbit/s up to 300 meters, widely used in modern data centers .
• OM4: 50 µm core, aqua jacket, enhanced laser-optimized, supports 10 Gbit/s up to 550 meters, 40/100 Gbit/s up to 150 meters, ideal for high-speed backbone networks .
• OM5: 50 µm core, lime or violet jacket, supports short-wavelength division multiplexing (SWDM) from 850–953 nm, optimized for 40/100/400 Gbit/s applications, but offers no extra benefit for standard 1G–100G transceivers .

Selection Guidelines

1. For new high-speed networks: Use OM3 or OM4 for 10–100 Gbit/s within data centers or enterprise backbones. OM4 is preferred for longer distances or future-proofing.
2. For WDM or multi-wavelength applications: Use OM5, especially if planning 40G/100G SWDM deployments.
3. For legacy or low-speed networks: OM1 or OM2 may suffice, but they are limited in distance and bandwidth and are generally being phased out .
4. Light source compatibility: Use LEDs for OM1/OM2 and VCSEL lasers for OM3/OM4/OM5 to achieve optimal performance .

Practical Considerations

• Cost: OM1 and OM2 are cheaper but limited in speed and distance. OM3/OM4/OM5 are more expensive but support higher data rates and longer distances.
• Distance: For runs beyond 300–550 meters at high speeds, consider single-mode fiber instead.
• Future-proofing: OM4 or OM5 is recommended for new installations to accommodate evolving network speeds and WDM technologies. In summary, OM3 or OM4 is the most practical choice for modern multimode fiber networks, with OM5 reserved for specialized WDM applications, while OM1 and OM2 are suitable only for older or low-speed setups .