Multimode fiber optic cable has been widely used in our daily life for its cost-effective, low power consumption and etc. The OM family recently was added a new member, called as OM5. Different from the previous OM1 to OM4, OM5 is a wideband multimode fiber, which will support short wavelength division multiplexing (SWDM). This article would provide general information about OM5 and differences between OM5 and OM3, OM4.
As early as 2016, Commonscope introduced their LazrSPEED Wideband Multimode Fiber (WBMMF), and the ISO/IEC decided the nomenclature for WBMMF is OM5 in October 2016. Later, wideband OM5 fiber was defined by IEEE 802.3bs, which refers as a multimode 400Gb/s link, 400GBASE-SR16, using 16 transmit and 16 receive fibers (32 fibers total) over a link distance of 100 m. Currently it shows that OM5 wider operating window offers no immediate advantages compared with OM4 fiber. But using OM5 will make the network ready for future use of SWDM technology.
At present, several major brands like Cisco, FIT, Finisar have been devoted to develop and research multimode WDM solutions that solve customer needs. And it seems that Finisar is a pioneer at this point. So far, Finisar has announced two products that offer SWDM using NRZ technology. One product is a 100G-SWDM4 transceiver. This transmits over four wavelengths at 25Gb/s per wavelength for an aggregated 100Gb/s. This product will support link distances of 70 m on OM3, 100 m on OM4 and 150 m on OM5. Moreover, OM5 does not support any existing optical transceiver but 100G-SWDM4 transceiver.
The most distinctive highlight of OM5 fiber is that it supports at least four short WDM channels simultaneously while OM3 and OM4 fiber only support one wavelength at a time. OM5 allows for 4 times the bandwidth than legacy OM4. That means the same amount of bandwidth dedicated to 8 fibers on OM4 can now transmit just 2 strands. Utilizing SWDM, you can transmit over 850 nm, 880 nm, 910 nm, and 940 nm simultaneously.
Attenuation testing at 850 nm and 1300 nm are sufficient to verify that the OM5 fiber meets 953 nm attenuation requirements. That is to say, the working wavelength of OM5 is between 850 nm and 953 nm while OM3 and OM4 between 850 nm and 1310 nm. It is common sense that the shorter the wave range, the less the attenuation. Thus, OM5 has right advantage on this aspect.
Based on 10 Gigabit Ethernet, the transmission distance of OM3 and OM4 can reach 300 m and 400 m respectively. OM5 fiber optical cable has the same maximum transmission distance as OM4.
As earlier in March this year, the TIA started TIA-598-D-2 to determine lime as the jacket color for cabled WBMMF (TIA-492AAE, OM5). And now, lime is the new aqua, which stands for the standard jacket color of OM3 and OM4.
Although it seems that OM5 has not the absolute advantage over OM4, but it can meet the requirement for a higher bandwidth in a long term. Selecting OM5 MMF will give you the flexibility in the future to easily add bandwidth without adding more fiber. Estimates claim that there will be 30 billion connected devices next year. Time would tell the OM5 multimode fiber will be the most cost-effective short-reach solution in the enterprise and data center on short-reach market.