Multimode optical fiber typically supports transmission distances from a few tens of meters up to about 550 meters, depending on the fiber type and data rate.

Overview of Multimode Fiber

Multimode fiber (MMF) has a larger core diameter, usually 50 or 62.5 micrometers, allowing multiple light modes to propagate simultaneously. This makes it ideal for short-distance communication within buildings, data centers, or campus networks, but it limits the maximum transmission distance due to modal dispersion, where light rays take different paths and arrive at slightly different times, causing signal spreading and degradation .

Distance Limits by Fiber Type

Multimode fibers are classified into OM1, OM2, OM3, OM4, and OM5, each with different performance characteristics:

• OM1 (62.5 µm core): Supports 1 Gbps up to 275 meters and 10 Gbps up to 33 meters. Commonly used for lower-speed LAN applications .
• OM2 (50 µm core): Supports 1 Gbps up to 550 meters and 10 Gbps up to 82 meters .
• OM3 (50 µm, laser-optimized): Supports 10 Gbps up to 300 meters, and higher speeds like 40/100 Gbps up to 100 meters .
• OM4 (50 µm, enhanced laser-optimized): Extends 10 Gbps links up to 550 meters, with 40/100 Gbps up to 150 meters .
• OM5 (50 µm, wideband multimode): Designed for shortwave wavelength division multiplexing, supporting similar or slightly longer distances than OM4 for high-speed applications .

Practical Considerations

• Data rate matters: Higher speeds reduce the maximum distance due to increased modal dispersion.
• Application: Multimode fiber is cost-effective for in-building backbones, data centers, and campus networks, while single-mode fiber is preferred for long-distance or metropolitan area networks .
• Signal quality: Attenuation and dispersion limit the effective length; using higher-quality fiber and laser-based transceivers can maximize distance . In summary, multimode optical cables are generally used for distances up to 550 meters, with exact limits depending on the fiber type, core size, and transmission speed. For longer distances, single-mode fiber is recommended.