Understanding the Differences Between OM1, OM2, OM3, OM4, and OM5 Multimode Fibers

Multimode optical fibers, abbreviated as OM (Optical Multimode), are categorized based on their core diameter, modal bandwidth, and performance characteristics. Each OM grade serves specific applications and supports different transmission distances and speeds in fiber optic networks.

OM1 Fiber:

Core Diameter: 62.5 micrometers (µm)

Modal Bandwidth (MHz·km): 200 MHz·km

Description: OM1 fiber was one of the earliest multimode fibers deployed in Ethernet networks. It supports Ethernet speeds up to 1 Gbps over short distances, typically up to 275 meters at 1 Gbps.

OM2 Fiber:

Core Diameter: 50 µm

Modal Bandwidth (MHz·km): 500 MHz·km

Description: OM2 fiber offers higher bandwidth than OM1, enabling longer transmission distances at higher speeds. It supports Ethernet speeds up to 1 Gbps over longer distances than OM1, up to 550 meters at 1 Gbps.

OM3 Fiber:

Core Diameter: 50 µm

Modal Bandwidth (MHz·km): 2000 MHz·km

Description: OM3 fiber supports 10 Gbps Ethernet at lengths up to 300 meters and is optimized for use with VCSEL (Vertical Cavity Surface Emitting Laser) sources. It is commonly used in data centers and enterprise networks for high-speed applications.

OM4 Fiber:

Core Diameter: 50 µm

Modal Bandwidth (MHz·km): 4700 MHz·km

Description: OM4 fiber provides higher bandwidth than OM3, supporting 10 Gbps Ethernet at longer distances of up to 550 meters. It is designed to accommodate higher speeds and longer link lengths in data centers and campus backbones.

OM5 Fiber:

Core Diameter: 50 µm

Modal Bandwidth (MHz·km): TBD (To Be Determined)

Description: OM5 fiber, also known as WBMMF (Wideband Multimode Fiber), is designed to support wavelengths in the range of 850 to 953 nm. It is optimized for use with Shortwave Wavelength Division Multiplexing (SWDM) technology, aiming to support multiple wavelengths over a single fiber. OM5 is intended to enhance the efficiency and scalability of data center networks.

Key Differences and Applications:

• Bandwidth and Distance: OM1 has the lowest bandwidth and shortest reach, suitable for older networks or short-distance applications. OM2 and OM3 offer improved bandwidth and distance capabilities, supporting higher speeds over longer distances. OM4 and OM5 provide the highest bandwidth and support for advanced applications like 40 Gbps and 100 Gbps Ethernet over extended distances.

• Technology Compatibility: Each OM grade is optimized for specific light sources and wavelengths, ensuring compatibility with the latest optical networking technologies and standards.

• Future-Proofing Networks: Upgrading to higher OM grades such as OM3, OM4, and OM5 future-proofs networks against increasing bandwidth demands and evolving technology standards.

In conclusion, selecting the appropriate OM grade depends on the specific application requirements, including desired speeds, transmission distances, and compatibility with existing network infrastructure. Understanding these differences helps network planners and installers make informed decisions when designing and deploying fiber optic networks.