OM3 and OM4 multimode fibers are commonly employed in local area networks (LANs), particularly for connecting backbone cabling between telecommunications rooms and in data centers for linking main networking and storage area network (SAN) switches. While these fiber types share similarities, they are distinct and can be confusing to users. Let’s clarify the differences.
What are OM3 and OM4 Fiber?
OM3 and OM4 are types of laser-optimized multi-mode fibers (LOMMF) tailored to support fast networks, including speeds of 10, 40, and 100 Gbps. They possess an identical fiber core size of 50/125. Additionally, both OM3 and OM4 are designed to work seamlessly with 850-nm VCSELS (vertical-cavity surface-emitting lasers).
OM3 vs OM4, What are the Differences?
OM3 vs OM4 Bandwidth
A significant contrast between OM3 and OM4 multimode cables lies in their modal bandwidth. OM4 boasts a notably higher modal bandwidth of 4700 MHz·km, surpassing OM3’s 2000 MHz·km. Modal bandwidth indicates a fiber’s capacity to transmit information across a specific distance. In practical terms, OM4 fiber can convey more data within the same distance compared to OM3 fiber. Modal bandwidth is influenced by modal dispersion in fiber cables. The elevated bandwidth offered by OM4 results in reduced modal dispersion, enabling longer cable links with lower losses or attenuation.
OM3 vs OM4 Speed
The OM3 fiber specification highlights its primary purpose of supporting a transmission speed of 10 Gb/s. However, it is also capable of accommodating speeds of 40 Gb/s and 100 Gb/s. Building upon the foundation of OM3, OM4 fiber takes a step forward and is notably employed for 10G, 40G, and 100G Ethernet connections.
Both OM3 and OM4 fibers can handle speeds of 40 Gb/s and 100 Gb/s, but this requires specific configurations. When equipped with 8/12-fiber MTP/MPO connectors, they can facilitate 40 Gb/s connections. Similarly, with 24-fiber MTP/MPO connectors, they become suitable for 100 Gb/s connections. In the case of 40G interfaces, they involve 4 separate 10G channels, each utilizing 4 fibers for transmission in both directions. For 100G interfaces, the setup involves 10 separate 10G channels, utilizing 10 fibers in each direction.
OM3 vs OM4 Attenuation
Attenuation refers to the reduction in the strength of an optical signal as it traverses passive elements like fibers, cable splices, and connectors. In terms of attenuation, OM4 outperforms OM3. Specifically, when measured at the wavelength of 850nm, the maximum attenuation for OM3 is 3.5 dB/km, while for OM4, it is even lower at 3.0 dB/km. This signifies that OM4 exhibits a reduced loss of signal strength over distance when compared to OM3.
OM3 vs OM4 Distance
The distance over which OM3 and OM4 fiber cables transmit signals varies depending on their application in Gigabit, 10GbE, 40GbE, and 100GbE setups. You can find the maximum transmission distances of OM3 and OM4 under different speeds in the figure below.
When it comes to 10, 40, and 100 Gb/s applications, OM4 fiber surpasses the distance capabilities of OM3. However, there’s some debate about the maximum distance OM4 can achieve under 10G speeds. Generally, it’s considered to be around 400 meters. However, it’s worth noting that under exceptional circumstances where the OM4 fiber quality is exceptionally high, it can actually reach up to 550 meters.
OM3 vs OM4 Color
Laser-optimized OM3 and OM4 multimode fibers both sport an aqua jacket when connected using LC connectors, leading to a shared appearance. This similarity poses a challenge for technicians who must differentiate between the two, especially when confronted with a panel displaying identical adapters. To address this concern, a new solution emerged in the form of a violet color for OM4, also referred to as Erika Violet. This violet OM4 color has been introduced in Europe and a few American companies, aiming to alleviate the identification issue.
When it comes to cables terminated with MTP/MPO connectors, OM3 cables feature an aqua jacket, while OM4 cables exhibit an Erika Violet jacket, thus providing a distinct visual cue to help differentiate between the two types.
OM3 vs OM4 Price
The cost of OM4 is slightly higher than that of OM3 due to its enhanced performance. However, this price difference is quite minimal and can be disregarded, thanks to advancements in manufacturing technology.
Is OM4 compatible with OM3?
OM4 fiber is entirely backwards compatible with OM3 fiber due to their shared core diameter. However, when mixing components with different performance levels, the overall performance will be limited to that of the lower-performing component. For example, if OM3 and OM4 fiber cables are combined, the performance achieved will be that of OM3.
OM3 vs OM4, How to Choose?
In most cases, for enterprise 10 GbE connections, which are generally under 300 meters, OM3 fiber cables are sufficient to meet the needs. However, the higher bandwidth of OM4 fiber also provides a suitable solution. When it comes to 40 GbE and 100 GbE links, there’s a slight discrepancy in transmission distances between OM3 and OM4 (OM3: 100 m, OM4: 150 m). If you require longer transmission distances, opting for OM4 multimode fiber is an excellent choice.
The choice between using OM3 or OM4 for your network depends on specific factors such as cost and the required transmission distance.
Conclusion
Following our in-depth exploration, you likely have a clearer grasp of the distinctions between OM3 and OM4 fibers, enabling you to make informed decisions to cater to your high-bandwidth system needs. At Bonelinks, we offer OM3 and OM4 multimode fibers that surpass global optical fiber standards, including ISO/IEC 11801, IEC 60793-2-10, and TIA-EIA. These fibers are versatile across applications like Ethernet, Fiber Channel, Infiniband, and more. Feel free to reach out to us for consultation at bonelinks.com. We’re here to assist you.
