Multimode Fiber: Differences Between OM1, OM2, OM3, OM4, and OM5

Multimode fiber is essential for short-distance communication, commonly utilized in campus networks, corporate LANs, and data centers. The market offers various types of multimode optical fiber, including OM1, OM2, OM3, OM4, and OM5, each with distinct data transmission capabilities. With so many options, choosing the right multimode fiber can be challenging. This guide explains the differences between OM1, OM2, OM3, OM4, and OM5 fibers to help you make an informed decision.

 

 

Types of Multimode Optical Fiber and Their Differences

Compared to single-mode fiber, multimode fiber features a larger core diameter, typically 50μm or 62.5μm, supporting multiple modes of light propagation. According to ISO/IEC 11801 standards, multimode fibers are categorized into OM1fiber, OM2 fiber, OM3 fiber, OM4 fiber, and OM5 fiber.

 

 

OM1 Fiber

OM1 fiber has a 62.5μm core diameter and operates at 850/1300nm with a bandwidth of 200/500 MHz.km. It uses LED light sources and is usually housed in an orange jacket. OM1 fiber is ideal for Ethernet applications below 10Gbps, commonly used in 100Mbps Ethernet. Its larger core diameter provides good light-gathering ability and bend resistance.

 

OM2 Fiber

OM2 fiber has a 50μm core diameter, operates at 850/1300nm with a bandwidth of 500/500 MHz.km, and uses LED light sources. It also comes in an orange jacket. OM2 is suitable for Ethernet applications below 10Gbps, commonly used in Gigabit Ethernet. The smaller core diameter of OM2 reduces modal dispersion, increasing bandwidth and lowering production costs by about one-third compared to OM1.

 

OM3 Fiber

OM3 fiber has a 50μm core diameter, using 850nm VCSEL laser sources. It has an aqua jacket and supports Ethernet applications below 100Gbps, typically used in 10Gbps Ethernet. OM3 fiber offers higher transmission rates and bandwidth than OM1 and OM2, thus it's also known as optimized multimode fiber or 10Gbps multimode fiber.

 

OM4 Fiber

An upgraded version of OM3, OM4 fiber has a bandwidth more than double that of OM3. It is compatible with OM3 and comes in an aqua jacket. In Ethernet applications above 10Gbps, OM4 fiber can transmit data over longer distances, up to 400 meters.

 

OM5 Fiber

The latest multimode fiber, OM5, is backward compatible with OM4. It has the same 50μm core diameter as OM2, OM3, and OM4, and comes in a lime green jacket. OM5 supports wider wavelength ranges, enabling higher data rates and improved performance in high-speed Ethernet applications.

 

 

Physical and Application Differences

Physical Differences

The main physical differences among OM1, OM2, OM3, OM4, and OM5 multimode fibers lie in their core diameters, outer sheath, optical sources, and bandwidth capabilities:

 

MMF Fiber Type	Core Diameter	Outer Sheath	Optical Source	Bandwidth (MHz.km)
OM1	62.5/125μm	Orange	LED	200
OM2	50/125μm	Orange	LED	500
OM3	50/125μm	Aqua	VCSEL	2000
OM4	50/125μm	Aqua	VCSEL	4700
OM5	50/125μm	Lime Green	VCSEL	28000

 

Application Differences

Different multimode fibers are used in varying Ethernet applications, with each supporting different maximum transmission distances:

 

Fiber Type	Fast Ethernet	1G Ethernet	10G Ethernet	40G Ethernet	100G Ethernet
OM1	2000m	275m	33m	/	/
OM2	2000m	550m	82m	/	/
OM3	2000m	550m	300m	100m	100m
OM4	2000m	550m	550m	150m	150m
OM5	/	/	550m	440m	150m

 

Trends and Applications in Multimode Optical Fiber

Driven by the need for high-speed networks, multimode fiber technology is advancing towards low-loss, high-bandwidth, and multi-wavelength solutions. From the initial OM1 fiber to the current OM5 fiber supporting 40/100G networks, performance has significantly improved.

 

Today, OM1 and OM2 fibers are typically used for 1G Ethernet links within server rooms, while OM3 and OM4 fibers are used for 10G/40G data center cabling. OM5 fiber is ideal for 40/100G high-speed Ethernet links. Compared to OM1, OM2, OM3, and OM4, OM5 fiber offers high scalability and flexibility, supporting higher data rates with fewer cores, and it has lower costs and power consumption than single-mode fiber. Thus, OM5 fiber is likely to be widely adopted in 100G/400G/1T large-scale data centers.

 

NADDOD provides a wide range of multimode optical fibers and transceiver modules, designed to meet the evolving needs of modern networking environments. Our products ensure seamless integration, high performance, and reliable connectivity.

 

FAQs for Multimode Fiber

1. What is the difference between multimode and single-mode fiber?

• Core Diameter: Multimode fibers have larger core diameters (50/62.5μm) and can transmit multiple light modes. Single-mode fibers have smaller core diameters (9μm) and transmit a single light mode.
• Bandwidth: Single-mode fibers typically offer higher bandwidth, up to 100,000GHz.
• Light Source: Multimode fibers generally use LED light sources, while single-mode fibers use laser light sources.
• Distance:Multimode fibers are suitable for short-distance applications, with maximum transmission distances up to 550 meters.
• Cost:Multimode fibers are generally less expensive than single-mode fibers.

Check more about the differences between multimode and single-mode fiber.

 

2. Types of Multimode Fiber Connectors

Common multimode fiber connectors include ST, SC, FC, LC, MU, E2000, MTRJ, SMA, DIN, and MTP/MPO. Among these, ST, SC, FC, LC, and MTP/MPO are the most widely used. Each type has different advantages and functions:

 

Connector Type	Ferrule Size	Insertion Loss
SC	φ2.5mm	0.25-0.5dB
LC	φ2.5mm	0.25-0.5dB
FC	φ2.5mm	0.25-0.5dB
ST	φ1.25mm	0.25-0.5dB
MTP/MPO	φ2.5mm	0.25-0.5dB

Note: The ferrule is a cylindrical structure inside the fiber connector plug that holds the fiber in place. It can be made from materials such as ceramic, glass, plastic, or metal.

 

3. Advantages of Multimode Fiber

While single-mode fiber has advantages in bandwidth and transmission distance, multimode fiber meets most indoor application and data center transmission distance requirements. It also has lower installation and maintenance costs. Key benefits include:

No Signal Loss Interference: Multimode fiber can carry multiple light signals simultaneously on a single link with minimal signal power loss. This ensures secure, interference-free transmission of multiple data packets.

Supports Multiple Protocols: Multimode fiber supports various data transmission protocols, including Ethernet, Infiniband, and Internet protocols, making it a reliable foundation for core applications.

 

4. Can Multimode Fiber Be Used as Single Mode?

No, multimode fiber cannot replace single-mode fiber due to higher dispersion and loss, which prevent long-distance transmission of light signals.

 

By understanding these differences and advantages, you can make more informed decisions about which multimode fiber type best suits your network needs. Explore NADDOD’s selection of high-quality multimode optical fibers and transceiver modules to enhance your network’s performance and reliability.