Brief introduction for OM5 Multimode Fiber

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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.

 

Information About OM5

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.

 

Differences Between OM5 and OM3, OM4

—Bandwidth

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

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.

 

—Transmission distance

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.

 

—Jacket color

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.

 

Conclusion

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.