The transmission distance of multimode fiber depends on fiber type, data rate, and light source, ranging from about 33 meters for OM1 at 10 Gbps to 400 meters for OM4 at 10 Gbps.

Overview of Multimode Fiber Types and Distances

Multimode fibers (MMF) are designed for short- to medium-range communication and have larger core diameters (50–62.5 µm) that allow multiple light modes to propagate. The main fiber types are OM1, OM2, OM3, OM4, and OM5, each optimized for different bandwidths and distances .

• OM1 (62.5/125 µm): Supports 1 Gbps up to 275 meters and 10 Gbps up to 33 meters using LED sources .
• OM2 (50/125 µm): Supports 1 Gbps up to 550 meters and 10 Gbps up to 82 meters .
• OM3 (laser-optimized 50/125 µm): Supports 10 Gbps up to 300–400 meters and 100 Gbps up to 100 meters using VCSEL lasers .
• OM4 (enhanced laser-optimized 50/125 µm): Extends 10 Gbps up to 400 meters and 100 Gbps up to 150 meters .
• OM5: Designed for wavelength division multiplexing (WDM), enabling longer distances at higher speeds, particularly for future high-speed applications .

Factors Affecting Transmission Distance

1. Modal Dispersion: Multiple light modes travel at slightly different speeds, causing pulse spreading and limiting distance .
2. Data Rate: Higher data rates reduce maximum distance; doubling the data rate roughly halves the achievable distance .
3. Light Source: VCSEL lasers provide narrower spectral width than LEDs, reducing modal dispersion and increasing distance .
4. Wavelength: Shorter wavelengths (850 nm) are typically used for MMF and support longer distances at high speeds .
5. Installation Quality: Poor connectors, excessive splices, or tight bends can reduce effective distance .

Practical Implications

For LANs and data centers, OM3 and OM4 fibers are preferred for high-speed connections due to their longer reach and higher bandwidth. OM1 and OM2 are suitable for lower-speed, short-distance applications. When distances exceed the MMF limits, single-mode fiber is recommended for longer reach and higher bandwidth flexibility . By selecting the appropriate fiber type and considering data rate, light source, and installation quality, network designers can optimize multimode fiber links for both current and future requirements .