For modern data centers, OM3, OM4, and OM5 multimode fiber cables are recommended for high-speed, short-reach connections, while OM1 and OM2 are largely legacy options.

Overview of Multimode Fiber Types

Multimode fiber (MMF) uses a larger core (50 µm or 62.5 µm) to carry multiple light modes simultaneously, making it cost-effective for short-distance data center connections using VCSEL or LED transceivers . MMF is ideal for intra-rack, inter-rack, and horizontal cabling within 300 meters, supporting speeds from 1G to 400G depending on the fiber type .

OM1 and OM2

• OM1: 62.5 µm core, orange jacket, LED light source. Supports 10G Ethernet up to ~33 meters. Mostly found in legacy networks; not recommended for modern high-speed deployments .
• OM2: 50 µm core, orange jacket, LED source. Supports 10G Ethernet up to ~82 meters. Suitable for older 1G/10G networks but limited for high-density data centers .

OM3 and OM4

• OM3: 50 µm core, aqua jacket, laser-optimized for VCSELs. Supports 10G Ethernet up to 300 meters, 40G/100G up to 100 meters. Cost-effective for current 10G/25G/40G deployments .
• OM4: 50 µm core, aqua jacket, enhanced laser-optimized. Supports 10G Ethernet up to 400 meters, 40G/100G up to 150 meters. Recommended for high-density, high-speed data centers with future-proofing for 400G short-reach links .

OM5

• OM5: 50 µm core, lime green jacket, designed for Short Wavelength Division Multiplexing (SWDM). Supports multiple wavelengths (850–940 nm), enabling 40G, 100G, and 400G SWDM4 links over a single fiber. Ideal for next-generation data centers requiring multi-wavelength, high-bandwidth applications . OM5 is backward compatible with OM4 for standard 850 nm transceivers.

Practical Recommendations for Data Centers

1. Intra-rack and horizontal patching (<100 meters): OM4 is generally the best balance of cost and performance, supporting 40G/100G links with LC duplex connections .
2. High-density, future-proof deployments: OM5 is recommended for SWDM applications and 400G-ready infrastructure .
3. Legacy networks: OM1 and OM2 may still exist but are not suitable for new high-speed deployments; consider upgrading to OM3/OM4 for cost-effective performance .
4. Connector types: LC duplex is standard for most data center patching; MPO/MTP connectors are used for high-density backbone or spine connections .

Summary

For modern data centers, OM3 and OM4 remain the most widely deployed multimode fibers for 10G–100G applications, while OM5 is recommended for future-proofing and SWDM-based 400G deployments. OM1 and OM2 are largely legacy and should be replaced in high-speed environments. Selecting the right fiber type ensures optimal bandwidth, lower latency, and cost-effective operation for short-reach, high-density data center networks .