Fiber Optic Cable

A Closer Look at OM5

We know that for short-reach optical interconnects, multimode fiber is a cost-effective solution. As data centers are constantly moving towards faster speeds and higher densities, the multimode fiber also has evolved over time, from OM1, OM2 to OM3 and OM4 multimode fiber. Now, OM5 is coming. This article will guide you to have a closer look at OM5.

Overview of OM5

OM5, also known as wide-band multimode fiber (WBMMF), is recognized within both the Telecommunications Industry Association (TIA) and International Electrotechnical Commission (IEC) standards. It is designed to support shortwave wavelength division multiplexing (SWDM) which would use 850nm, 880nm, 910nm and 940nm for transferring signals.

OM5

Characteristics of OM5

What makes OM5 different? What are characteristics of OM5? The following part will make a summary.

Size: OM5 fiber is laser optimized multimode fiber (LOMF) of 50 micron core. Therefore, OM5 cabling supports all legacy applications at least as well as OM4, and is fully compatible and intermateable with OM3 and OM4 cabling.

Color: TIA has specified lime green as the official cable jacket color for OM5.

Bandwidth: The operating band of OM5 is from 850 to 953nm and its effective modal bandwidth is specified at the lower and upper wavelengths: 4700 MHz.km at 850nm and 2470 MHz.km at 953nm.

Speed: OM5 can support 40G, 100G and 400G Ethernet by accommodating SWDM. And it is designed and specified to support at least four WDM channels at a minimum speed of 28Gbps per channel through the 850-953 window.

Distance: When transferring signals at the speed of 10 Gb/s, OM5 can achieve 550 meters; when transferring signals at the speed of 40 Gb/s, OM5 can achieve 440 meters; when transferring signals at the speed of 100 Gb/s, OM5 can achieve 150 meters.

Working principle: Since SWDM will enable 40G and 100G over few fiber strands, when using 25GBASE-SR specifications, 100 gigabit OM5 fiber links could be created using 2-fiber 25 gigabit channels on 4 different wavelengths. Similarly, using 100GBASE-SR4 specifications, 400 gigabit OM5 fiber links could be created using 8-fiber 100 gigabit channels on 4 different wavelengths.

Cost: As the matter of fact, OM5 cabling will costs about 50% more than OM4.

Comparison Among OM5, OM4 And OM3

By comparison, it is not difficult to find that there are many differences between OM5, OM4 and OM3.

  • OM5 carries at least 4X more capacity than OM4 over a meter of fiber and carries 5.7X more capacity than OM3 over a meter of fiber.
  • The color of OM5 fiber is lime green, while standard OM3 and OM4 fiber is aqua.
  • The effective modal bandwidth for OM5 is 4700 MHz.km at 850nm and 2470 MHz.km at 953nm. While OM4 is 4700 MHz.km at 850nm and OM3 is 2000 MHz.km at 850nm.
  • For 100 transmission speed, OM5 uses 2-fiber 25 gigabit channels on 4 different wavelengths, while OM4 and OM3 requires the use of 8-fibers via 100GBASE-SR4.
  • OM5 supports transmission distance of 440 meters for 40G SWDM system and 150 meters for 100G SWDM system. While OM4 can only achieve 350 meters for 40G SWDM system and 100 meters for 100G SWDM system; OM3 can support 40G SWDM system with distance of 240 meters and 100G SWDM system with 75 meters.

Conclusion

As a new type of multimode fiber, OM5 fiber does have a breakthrough in some aspects. However, it is not very popular on the market. Maybe because its strength is not prominent. Therefore, for OM5, it still has a long way to go.

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