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OM3 And OM4 Fiber Cable for 10G/40G/100G Network

Highly appreciated by Ethernet users and most widely recognized in network backbones, multimode fiber offers users the opportunity to extend link distances, increase network reliability, and reduce costs by centralizing electronics.
With the introduction of the OM1 fiber series in the mid-1990s, the production of OM 3 fibers coincided with the market. The advantage of OM2 fiber is that it is more efficient and cost-effective to use optimized fiber - more efficient than traditional fiber - right up to the node system (FTTN). The advantage of OM3 fiber is the use of laser-optimized fiber, which is the medium with the largest transmission capacity for short-wave 10G light. OM4 fiber is the addition of multimode fiber series after OM3 fiber to meet the requirements of longer distance applications. OM5 fiber and om4 fiber expand the multimode fiber family to meet the requirements of long-distance applications.
This article will briefly introduce OM3 and OM4 fibers, further analyze their differences and selection guidelines, and list their applications.

OM3 & OM4 Fiber

Both OM3 and OM4 fiber meet the ISO 11801 standard. The standard specifies that OM3 fibers are capable of 10 Gb/s performance over distances of up to 300m. Like being mentioned, the laser optimized 50/125 mm multimode OM3 fiber is of predominance, which provides sufficient bandwidth to support 10 GbE and beyond with cable lengths up to 550 meters. OM4 fiber is a further improvement to OM3 fiber. It also uses a 50µm core but it supports 10 Gigabit Ethernet at lengths up 550 meters and it supports 100 Gigabit Ethernet at lengths up to 150 meters.

OM3 vs OM4 Multimode Fiber: What's the difference?

Optical attenuation

Attenuation is caused by losses in light through the passive components, such as cables, cable splices, and connectors. Attenuation is the reduction in power of the light signal as it is transmitted (dB). The maximum attenuation of OM3 and OM4 fiber allowed at 850nm: OM3<3.5 dB/Km; OM4 <3.0 dB/Km. So it is obvious that OM4 fiber causes lower losses due to different construction.

Modal dispersion

As is known to most people, modal dispersion attaches great importance to bandwidth. The lower the modal dispersion, the higher the modal bandwidth, and the greater the amount of information that can be transmitted. The minimum OM3 and OM4 fiber cable bandwidth at 850nm: OM3 2000 MHz·km; OM4 4700 MHz· km. The higher bandwidth available in OM4 means a smaller modal dispersion and thus allows the cable links to be longer or allows for higher losses through more mated connectors.

OM3 vs OM4 Speed

The OM3 fiber spec indicates that OM3 fiber is mainly designed for 10 Gb/s transmission speed, but it also can run under 40 Gb/s and 100 Gb/s. As an advancement of OM3 fiber, OM4 fiber is chiefly used for 10G, 40G and 100G Ethernet. Both OM3 and OM4 fibers support 40 Gb/s and 100 Gb/s speeds when they are terminated with 8/12-fiber MTP/MPO connectors and 24-fiber MTP/MPO connectors respectively. The 40G interfaces are 4x10G channels on four fibers per direction and the 100G interfaces are 10x10G channels on 10 fibers per direction.

OM3 vs OM4 Distance

What is the maximum distance OM4 will support 10 Gigabit Ethernet?
The maximum transmission distance of OM4 fiber is 400–550m (depending on module capability) while OM3 fiber can only be up to 300m. And thus, OM4 can tolerate a higher level of loss at distances between 200–300m as it is designed to operate at longer distances than OM3 fiber. It may be a more flexible option for network managers to install OM4 fiber within these instances. You can check the difference between OM3 and OM4 in transmission distance in the following table.
850 nm Ethernet Distance (m)
Fiber Type 1G 10G 40G/100G
OM3 1km 300m 100m
OM4 1km 550m 150m
OM4 fiber distance is longer than OM3 fiber distance based on 10, 40 and 100 Gb/s. But the maximum transmission distance of OM4 under 10G remained controversial. As a rule of thumb, it is recognized as 400 m. But it still can achieve up to 550 m if the OM4 fiber has an ultra high quality.

OM3 vs OM4 Bandwidth

One big difference between OM3 and OM4 multimode cable is that OM4 provides a higher modal bandwidth 4700 MHz·km compared to 2000 MHz·km of OM3. Modal bandwidth characterizes the ability of a fiber to transmit a certain amount of information over a certain amount of distance, which means OM4 fiber can transmit more information within the same distance than OM3 fiber. And the modal bandwidth is determined by the modal dispersion in fiber cables. The higher bandwidth available in OM4 means a smaller modal dispersion and thus allows the cable links to be longer with lower losses or attenuation.

OM3 vs OM4 Price

In comparison to OM3 fiber, the cost for OM4 is higher due to the manufacture process and market fluctuations. In a large extent, cost depends on the construction type of the cable (loose tube, tight-buffered, etc.). OM4 fiber cable is about twice as expensive as OM3 fiber cable. This means that the cost difference of lots of fiber products such as standard fiber patch panels, MTP cassette modules, fiber patch cords is very small (as the volume of cable is small).In Heyoptics, the price difference between OM3 and OM4 optical cable is very small, and the price is favorable, which has an absolute advantage in the market.

Should I use OM3 or OM4?

Fifty micron OM3 fiber is designed to accommodate 10 Gigabit Ethernet up to 300 meters, and OM4 can accommodate it up to 550 meters. Therefore, many users are now choosing OM3 and OM4 over the other glass types. In fact, nearly 80% of 50 micron fiber sold is OM3 or OM4. If you require higher data rates or plan on upgrading your network in the near future, laser optimized 50 micron (OM3 or OM4) would be the logical choice. Compared to OM4, OM3 fiber is more future proofing for most applications, which allows speeds of 10 GB/s up to 100 GB/s. OM4 fiber provides users a transmission solution over longer distances and leaves more wiggle room in optical budgets.
OM3 and OM4 fiber cables are typically used in data center structured cabling environments running high speeds of 10G or even 40 or 100 Gigabit Ethernet, SAN (Storage Area Networking), Fiber Channel, FCOE (Fiber Channel Over Ethernet) with such manufacturers as Cisco, Brocade, EMC and others. Typical applications could be virtualized or internal cloud core data center applications. For 40G and 100G fiber cable applications, MTP/MPO cable would also be a great choice. MTP cabling assemblies (MTP/MPO trunk cable, MTP/MPO harness cable, MTP/MPO conversion cable, etc), with their overwhelming advantages, providing a fast, simple and economical upgrade path from 10 Gigabit to 40 or 100 Gigabit applications.

FAQ about OM3 vs OM4 Multimode Fiber

Can OM3 support 40G? Can OM3 support 10G?

Yes, OM3 And OM4 Fiber Cable for 10G/40G/100G Network

Can I Mix and Match OM3 and OM4 Fiber Cable?

The vast majority of enterprise 10 GbE link lengths are less than 300 meters so OM3 fiber cable can meet most requirements. Of course, the OM4 with higher bandwidth could address these as well. For 40 GbE and 100 GbE links, OM3 and OM4 fiber have a subtle difference in transmission distance (OM3 for 100 m, OM4 for 150 m). If you need longer transmission distance, OM4 multimode fiber is an ideal option.
For OM3 and OM4 compatibility, OM4 fiber is completely backwards compatible with OM3 fiber since they have the same core diameter. However, when connecting two products with different performance levels, the best performance that can be expected will be that of the lower performing component. For example, if one mixes the OM3 and OM4 fiber cable, the best performance that can be expected is that of OM3.


Both OM3 fibers and OM4 fibers are laser-optimized multimode fibers with 50/125µm cores and are required to meet ISO 11801 standards. They have a lot in common, such as fiber optic connectors and application scenarios. In this article, we mainly discuss OM3 fiber, and OM4 fiber, their main differences, transmission guidelines, and applications for 10G/40G/100G networks. We focus on OM3 and OM4 fiber 10G/40G/100G transmission distance and a selection guide. OM3 and OM4 multimode fiber provide a cost-effective solution for interior buildings or corporate campuses. I hope this article was helpful for you to understand OM3 and OM4 fibers and choose the right cable for you.


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