It is recognized that multimode fiber cable (MMF) is always a cost-effective cabling solution for short distance transmission, including OM1, OM2, OM3 and OM4. Nowadays an updated type of multimode fiber cable named OM5 has gained widespread attraction among researcher and specialist in optical communication. Is this kind of MMF cable also a good choice for data center cabling? What are the main differences between OM1, OM2, OM3, OM4 and OM5? Can OM5 perform better than OM4 and other MMF cables? Let’s explore the answers.
OM5 is a new 50/125µm multimode optical fiber mainly designed for 40G and 100G data center standardized by TIA and IEC and released in last June. Then in this February, the color of OM5 has also identified, lime green, which is different from that of other MMF cables. Also, the color for OM5 connector and adapter housing should be different for easy identification. However, the OM5 connector and adapter types don’t change which means OM3 and OM4 connector and adapter are still suitable for OM5.
OM5 was initial called wideband multimode fiber (WBMMF) because it specifies a wider range of wavelengths between 850nm and 953nm at the same time for Wavelength Division Multiplexing (WDM) application, while other MMF cables are always used to support one wavelength a time. The WDM technology utilizes OM5 can be called SWDM (the letter S stands for shortwave). Due to this feature, OM5 enables a higher bandwidth network cabling that supports 40G, 100G and beyond.
OM1, OM2, OM3, OM4 vs OM5
As we know, OM1 is the only one 62.5/125um MMF cable always used in 1G application, while OM2 has a smaller core diameter, 50um that supports 1G network at a longer length, 550 m. Different from these two MMF cable mentioned above, 50/125um OM3 is designed to support 10G network at lengths up to 300 m and 40G network at lengths up to 100 m. As for OM4, it came into the market since 2005, as premium OM3. With its help, the 10G transmission link up to 400m and 40G/100G transmission link up to 150m can be achieved.
When it comes to OM5, its core diameter is still 50um and the transmission distance it supports is also the same to that of OM4, as shown in the following table. Then what’s the benefits of OM5, in contrast to the MMF cables mentioned before? Will it supports faster transmission rate? Will it cost less under the same condition? Is it an ideal solution for future-proof network?
OM5 Advantage: Compared to other MMF cables, OM5 supports at least four low-cost wavelengths in the 850-950 nm range, which enables the emerging SWDM applications. As the fiber counts the SWDM application needs is reduced, both higher speed and longer transmission can be achieved by using OM5. In short, OM5 utilizing SWDM technology is able to transmit 40G signals with reach up to 450 m and 100G signals with reach up to 150 m.
OM5 Disadvantage: Firstly, it should cost about 50% more to deploy OM5 cabling, in contrast with the OM4 one, which means OM5 is not an cost effective solution for future-proof network. Moreover, although single-mode fiber OS2, multimode fiber OM5 are feasible for 100/200/400G application, OM5 is still not commonly used due to the short transmission link it can support. Hence, to meet the future-proof network needs, single-mode fiber would be more suitable if high transmission rate and long transmission distance are required.
Currently, OM5 is recommendable for 40G SWDM applications, so that the maximum transmission distance can be extended from 150 m to 450 m. Except for that, there is no any other good reason to recommend OM5 to large data center operators. For example, for migrating to short distance 40G/100G network, OM3 and OM4 apparently offer benefit over OM5; and for migrating to long haul 40G/100G network, single mode fiber is more recommended. We can’t deny that OM5 will bring changes to data center, but there is still a long way to go. We’ll keep up-to-date with OM5 if there is any news updated.