Guide To Multimode Fiber (62.5um & 50um, OM1 to OM5)

Multimode fiber optic cable is a common specification of fiber optic glass which offers a much wider core size or core diameter of 50-62.5 nanometers compared to the more narrow core diameter of single-mode glass (9 microns across). Aside from the physical core diameter, there are many other variations in the physical properties of this material that make it an ideal choice for customers seeking high-speed, high-capacity bandwidth, and are looking for a shorter transmission distance. Multimode glass typically operates at a wavelength of 850 nm compared to the 1310 and 1550 nm spectrum used for single-mode glass transmission.

For instance, multimode fiber patch cords help to connect governments and businesses to data centers for data storage, backup and recovery, data management, and networking. While most of the long span cables used in longer distances of 1+ kilometer use SM glass, interbuilding links often utilize multimode fiber. Additionally, applications like wavelength division multiplexing swdm (or CWDM) take advantage of the multiple modes available in order to transmit more complex data streams through the glass.

Many variables are considered when choosing between single-mode and multimode fiber – an engineer must also understand which type of multimode fiber is best suited for their application. If you didn’t already know, there are 5 commonly used multimode fiber types used in most industries worldwide. Most common are are OM1, OM2, OM3, OM4, and OM5 multimode fiber cable. Beyond these widely used variations, some industries such as mining or sensing applications may utilize multimode fiber with a plastic core instead of glass, while some applications require fiber with a much larger core diameter of 200+ nanometers. We won’t discuss these uncommon but interesting types of glass and only focus on the most common variations from OM1 to OM5.

With so many options, it can be tough to select the most suitable multimode cable for your network needs. You may find yourself asking – What’s the difference between OM1 multimode cable and OM5 multimode cable? What about all those other fiber types in between? And which one is right for my network? This quick read will have the answer.

What is Multimode Fiber?

Multimode fiber is versatile enough to support the most commonly used connector types. For example, a multimode cable can be paired with LC, SC, FC, and ST connectors. Single mode fiber has a much smaller glass core and uses only one mode of light. Multimode cable has a larger core diameter which enables it to transmit more data using multiple modes of light.

The letters “OM” stand for optical multi-mode. OM1 has a glass core diameter of 62.5μm (micrometers). The rest of the fiber types – OM2, OM3, OM4, and OM5 – have a smaller core diameter of 50μm, which is better optimized for use with modern lasers. But, most importantly, the practical differences between all the multimode fiber types are the various thresholds for carrying data over certain distances.

Multimode Fiber Comparison Chart:

OM1 Patch Cable


  • OM1 Fiber – Usually comes in an orange jacket, according to industry color-coding standards, and can support a 10Gb Ethernet at lengths up to 33 meters (110 ft). This type commonly uses an LED light source.

OM2-OM3 Patch Cable


  • OM2 Fiber – Able to carry 10Gb Ethernet up to 82 meters (270 ft) on an LED light source. It can be found in orange and aqua jackets.
  • OM3 Fiber – Supports 10Gb Ethernet at lengths up to 300 meters. Instead of LED light, the OM3 cable’s design makes it optimized for laser transmission to help support 10Gb, 40Gb, and 100Gb Ethernet for up to 75 meters. OM3 cable is distinguished by an aqua jacket.

OM4 Patch Cable

  • OM4 Fiber – Sharing the same aqua jacket as OM3, OM4 also supports laser transmission beyond 150 meters and can carry 10Gb Ethernet up to distances all the way up of 550 meters. For higher bandwidth applications, OM4 can still transmit 100Gb up to 100 meters. Some versions of OM4 cable have a magenta jacket. OM4 fiber is commonly called ‘laser optimized.’

OM5 Patch Cable


  • OM5 Fiber – The latest iteration of the OM cable, OM5 packs some muscle that can carry high bandwidth for short to medium distances. What distinguishes OM5 from the rest is that it can achieve high bandwidth over short-range distances using fewer cables. Traditionally, 400Gb Ethernet was achieved using 16 transmit and receive cables, but with OM5 cables you can accomplish this with just four transmit and receive cables. It always comes in a lime-green jacket.

How is OM5 Different?

When compared to the capabilities of an OM4 cable, OM5 does not look like it has many advantages other than its jacket color. But dig a little deeper, and you’ll discover that OM5 supports a specific technology called short wavelength division multiplexing (SWDM4). In short, OM5 reduces the fiber count by at least a factor of four. For example, OM5 allows for the use of two fibers rather than 8 for transmitting 40Gb to 100Gb in short-range applications. Also, OM5 increases distance 50% over OM4 for customers using WDM (wavelength division multiplexer). This jump in distance is made possible through additional specifications of effective bandwidth and attenuation. To simplify, if you’re utilizing 40Gb to 100Gb SWDM, OM5 might be a solution for you. If not, go with the more affordable options of OM3 or OM4.

Contact the Megladon team today for help with all types of patch cables!

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About Megladon

A global industry leader in fiber optics and your premier partner for fiber optic connectivity, Megladon has spent over a decade developing fiber optic technology and perfecting the HLC interconnect. Our patented technology and process results in a reference grade interconnect that is reliable, rugged, repeatable and provides maximum performance. With millions of our products deployed worldwide, our fiber optic technology has been proven time and again to solve many of the problems encountered in network deployment and maintenance. We have also been able to use HLC as the foundation piece to develop unique and passive fiber optic solutions for our customers.