Guide to Selecting Multimode Fiber OM1 to OM5 Compared

When building or upgrading a fiber optic network, the variety of multimode fiber types can be overwhelming. OM1, OM2, OM3, OM4, and the latest OM5—what sets them apart? Which fiber truly meets your network needs while avoiding unnecessary investment? This article demystifies these five mainstream multimode fibers, detailing their characteristics and applications to help you make an informed choice.

Multimode fiber (MMF) is a critical part of fiber optic networks, particularly suited for short to medium-distance data transmission. Unlike single-mode fiber, MMF allows light signals to propagate through multiple paths or modes within the core. This characteristic offers advantages in cost-effectiveness and ease of use but also introduces certain performance limitations.

As network technology evolves, MMF has undergone multiple iterations—from the early OM1 to the current OM5—each designed to enhance bandwidth, transmission distance, and signal integrity. Understanding these variations is essential for building high-performance, scalable networks.

• Core Diameter: Typically ranges between 50 µm and 62.5 µm, varying by fiber type. The core diameter directly influences how light signals travel and their efficiency.
• Bandwidth: Different MMF types support varying bandwidth levels, determining data speed and transmission distance. Higher bandwidth enables greater data capacity.
• Light Propagation: Fiber types differ in signal transmission efficiency, affecting performance over distances. Advanced fibers generally exhibit lower loss and higher signal quality.

MMF remains popular in network applications due to its significant benefits:

• Cost-Effective: More economical than single-mode fiber, especially for short-distance applications, making it ideal for budget-conscious organizations.
• Ease of Installation: Larger core diameter simplifies handling and alignment, reducing installation complexity—a key advantage for rapid deployment or maintenance.
• High Bandwidth Potential: Newer types like OM3, OM4, and OM5 offer substantially improved bandwidth, supporting faster data rates.
• Support for Higher Data Rates: OM3, OM4, and OM5 can handle speeds up to 400 Gbps, catering to high-performance applications in data centers and enterprise networks.
• Ideal for Short Distances: Suited for short-to-medium-range transmission, such as within buildings, campus networks, or adjacent data centers.
• Future-Proof Upgrades: OM5 is designed for next-gen technologies, ensuring scalability as network demands grow.

OM1, an early MMF variant, features a 62.5 µm core diameter but suffers from higher modal dispersion, limiting its bandwidth compared to newer types.

• Core Diameter: 62.5 µm
• Bandwidth: 200 MHz·km (at 850 nm)
• Transmission Distance: 300 meters at 1 Gbps; 33 meters at 10 Gbps

OM1 is typically used in legacy systems with low-speed requirements, such as traditional setups in educational institutions or small businesses.

OM2 shares a similar core diameter (50 µm) but delivers better performance, making it suitable for moderate-distance applications requiring higher speeds.

• Core Diameter: 50 µm
• Bandwidth: 500 MHz·km (at 850 nm)
• Transmission Distance: 550 meters at 1 Gbps; 82 meters at 10 Gbps

Common in corporate networks and data centers where moderate distances and higher data rates are needed, such as backbone connections between servers and switches.

OM3 represents a significant upgrade, optimized for laser-optimized transmission and higher data rates over longer distances.

• Core Diameter: 50 µm
• Bandwidth: 2000 MHz·km (at 850 nm)
• Transmission Distance: 300 meters at 10 Gbps; 100 meters at 40 Gbps

Widely used in modern data centers and enterprise networks supporting cloud computing, virtualization, and 10 Gigabit Ethernet (10GbE) systems.

OM4 outperforms OM3 with higher bandwidth and extended transmission distances, ideal for high-performance computing and 100GbE networks.

• Core Diameter: 50 µm
• Bandwidth: 4700 MHz·km (at 850 nm)
• Transmission Distance: 400 meters at 10 Gbps; 150 meters at 40 Gbps

Suited for large data centers, high-speed backbone networks, and systems requiring 100GbE support.

OM5, the latest iteration, supports shortwave wavelength division multiplexing (SWDM), enabling multiple wavelengths over a single fiber for increased capacity.

• Core Diameter: 50 µm
• Bandwidth: 20000 MHz·km (at 850 nm)
• Transmission Distance: 400 meters at 100 Gbps; 70 meters at 400 Gbps

Designed for cutting-edge speeds in data centers and enterprise networks, OM5 excels in 100GbE and 400GbE environments with high-density demands.

• Network Scale & Requirements: Small networks with low-speed needs may use OM1/OM2, while larger, high-performance networks require OM3/OM4/OM5.
• Distance & Bandwidth: OM4 and OM5 excel in longer distances with higher bandwidth.
• Future-Proofing: OM3, OM4, or OM5 ensure readiness for growing data demands.

OM1 has a 62.5 µm core and lower bandwidth, while OM2’s 50 µm core offers better performance for moderate-distance, higher-speed applications.

OM3 supports 300 meters at 10 Gbps and 100 meters at 40 Gbps, ideal for mid-range high-speed uses like data centers.

Yes. OM4 provides higher bandwidth (4700 MHz·km) and longer distances (400+ meters at 10 Gbps), suited for high-performance networks.

Shortwave Wavelength Division Multiplexing (SWDM) allows multiple wavelengths over one fiber, boosting capacity in high-density setups.

No. Mixing types in a single link may cause signal loss and performance degradation. Always use matching fibers for optimal results.

Selecting the right multimode fiber—whether OM1, OM2, OM3, OM4, or OM5—depends on your network’s speed, distance, and scalability needs. While older types suffice for basic requirements, advanced fibers like OM4 and OM5 are indispensable for high-performance, future-ready networks.