What do OM1, OM2, OM3, and OM4 Fiber Mean?

When we talk about fiber optic networks, a lot of options are available to design a network. But the question is, which cable would work best for networking?

Let’s start with the basics to help you understand the critical variations in the design of cables.

Types Of Fiber Optic Cables Are Used In Telecommunication:

A.Single Mode cable prefixed with ‘OS.’

1. Multimode cable prefixed with ‘OM.’

A.   OS CABLES

OS cables have thinner cores (9-micron core), whereas OM cables have thick cores, which can be over 100 microns.

OS cables come in OS1, and OS2 fiber builds. OS1 is designed for distances below 2 km, whereas OS2 is for long-range networking up to 200 km.

B.   OM CABLES

Multi-mode fiber is quite cost-effective for installations where lengths are in a few hundred meters and can be used inside buildings or corporate campuses. By opting for a pre-terminated fiber optic cable, the overall cost can be brought down significantly. In contrast, the single-mode fiber is worth longer distance runs.

Usually, multimode fiber achieves 10 Gbit/s speed for 550m maximum transmission distance. Optical multimode fibers have a larger core size, typically a core diameter of 50 µm (OM2-OM5) or 62.5 µm (OM1).  More core means manifold modes of light travel down the core simultaneously, which means more data can pass through at a given time. Hence, the name is ‘multimode.’

Types Of Multimode Fiber

According to ISO 11801 standard, multimode fiber optic cables can be bifurcated into five grades:

1. OM1 fiber
2. OM2 fiber
3. OM3 fiber
4. OM4 fiber
5. OM5 fiber (released recently).

But what exactly makes them different?

These fibers can be differentiated on the basis of core size, data rate, bandwidth, color, distance, and optical source.

Starting with the properties of each type of Multimode fiber:

 

OM1 Fiber

• Covered with an orange jacket.
• Has a core size of 62.5 micrometers.
• Supports 10 Gigabit Ethernet at lengths up to 33 meters.
• Often used for 100 Megabit Ethernet Applications.
• Uses LED light source.

 

OM2 Fiber

• Jacket color is orange.
• Has a core size of 50 micrometers.
• Supports 10 Gigabit Ethernet at lengths up to 82 meters.
• Commonly used for 1 Gigabit Ethernet Applications.
• Uses LED light source.

 

OM3 Fiber

• Jacket color is aqua.
• Has a core size of 50 micrometers.
• Runs 10 Gigabit Ethernet at lengths up to 300 meters.
• Can support 40 Gigabit and 100 Gigabit Ethernet up to 100 meters.
• Commonly used for 10 Gigabit Ethernet Applications.
• Optimized for laser band equipment.

 

OM4 Fiber

• Has the Aqua jacket color.
• Has a core size of 50 micrometers but an improved version of OM3.
• Holds 10 Gigabit Ethernet at lengths up to 550 meters and supports 40/100 Gigabit
• Ethernet at lengths up to 150 meters utilizing an MPO connector.
• Specifically developed for VSCEL laser transmission.

 

OM5 Fiber

• It was released in 2014 and is also known as ‘Wideband Multimode Fiber” (WB MMF).
• The color of the jacket is lime green.
• Have similar characteristics to OM4 (same EMB and distance limitations of 10/40/100 GB Ethernet).
• It is specifically designed to support a minimum of four WDM channels at the slightest speed of 28 Gbps per channel through the 850-953 micron window.

 

MMF Cable Type	Jacket Colour	Optical Source	Diameter	Bandwidth
OM1	Orange	LED	62.5/125µm	200MHz*km
OM2	Orange	LED	50/125µm	500MHz*km
OM3	Aqua	VSCEL	50/125µm	2000MHz*km
OM4	Aqua	VSCEL	50/125µm	4700MHz*km
OM5	Lime Green	VSCEL	50/125µm	28000MHz*km

 

 

Points to remember while choosing a multimode fiber

• Due to the difference in core size of OM1 (62.5 micrometer), it is not directly compatible with other types of multimode, whether OM2, OM3, OM4, OM5, and neither can accept the same connectors.

 

• Please do match the core size for mechanical connectors to ensure signal continuity through the connector.

 

• The outer jacket of both OM1 and OM2 is orange in color. It is always advisable to check the print legend on the cable if the correct connector is used.

 

• Earlier, OM1, and OM2 were designed with LED transmitters, but later, due to modulation limitations of LEDs and the need for increased speed, laser-optimized multimode fibers (LOMMF) OM3 OM4 and OM5 were introduced.

 

Please note:

 

• For short runs, OM1 fibers are cost-efficient.

 

• Transmission makes a major difference. Though OM1 and OM2 are low in cost and hit top speeds of around 1Gbps, both uses LED transmitters and LED limits bandwidth.

 

• As OM3 and OM4 both utilize laser-optimized multimode (LOMMF) transmission, it is expensive to use but enables higher bandwidths and can speed up to 10 Gbps and 40 Gbps, respectively.

Advantages of Multimode Fiber

 

Multi-user framework

Multi-mode fiber carries multiple signals at the same time in the same line without any interference and alteration.

 

Support of multiple protocols

Multimode fiber can be used for high-value applications as it can support various data transfer protocols such as Ethernet, Infiniband, and Internet protocols.

Cost-effective

Multimode fiber can work with optical components like fiber connectors and fiber adapters and are easy and cost-efficient to install, operate and maintain.

Wrapping Up

Hopefully, the above details on Multimode fiber would be helpful. Falcon Technologies Inc. has a large variety of fiber optic cables. Depending on the application, transmission distance, and budget, you can choose which fiber cable is suitable for your project? If not sure, connect to our fiber cable experts to help you decide the suitable cable fiber.