Duplex 100G optical fiber transmission

Since the specification of OM5, Wideband Multimode Fiber (WB-MMF), users considering upgrading existing infrastructure or building new infrastructure have asked the question: should they deploy OM5 fiber?

OM5 fiber

First, let's discuss what exactly OM5 broadband multimode fiber is.

OM5 is essentially an OM4 fiber with additional bandwidth specifications at 953nm. Both OM4 and OM5 have a bandwidth of 4,700MHz•km at 850nm, while the bandwidth specification of OM5 is defined as 2,450MHz•km at 953nm. OM4 does not define the corresponding bandwidth specification under 953nm.

The OM5 is designed for shortwave wavelength division multiplexing (SWDM) optical transceiver applications. This new type of SWDM transceiver module uses four wavelengths, spanning from 850nm to 953nm, and can transmit 100Gbps links.

Each wavelength will be modulated at 25Gbps, and by multiplexing these wavelengths, the entire link can reach 100Gbps applications. Considering the wavelengths used in SWDM shortwave wavelength division multiplexing optical modules, it can be very convenient to understand why the OM5 standard was developed.

Notes: 1. Four Lasers four laser light sources; 2. Four Detectors four detectors; 3. The design of OM5 can be used for optical modules using short-wavelength wavelength division multiplexing.

multimode fiber

OM5 standard

If you plan to use SWDM short-wavelength wavelength division multiplexing optical modules to deploy 100Gbps links and need to reach a distance of more than 100 meters, then you only need to consider using OM5 broadband multimode fiber.

The benefit of using SWDM optical modules is that they allow the deployment of 100Gbps links over duplex MMFs instead of occupying the eight parallel fibers required when using 100GBASE-SR4. SWDM shortwave wavelength division multiplexing technology allows reuse of existing infrastructure based on duplex fiber optic transmission system components.

However, there are many more ideal alternatives to deploying 100Gbps over duplex fiber, such as 100G BiDi, or using PAM4 modulation to achieve higher data rates.

Other alternatives do not suffer from the disadvantages of SWDM shortwave wavelength division multiplexing optical modules, such as higher cost, operating temperature, and inability to support branching applications. If you still consider using SWDM 100G shortwave wavelength division multiplexing optical module, and the transmission distance is within 100 meters, then a compromise is to use the standard OM3 or OM4, because their price is lower than OM5.

If longer distances are required, say, with 40G BiDi, the best alternative to OM5 fiber is our OM4 Signature Core MMF. Our OM4 Signature Core MMF can reach a transmission distance of 200 meters with 40G BiDi, while OM5 can only reach 150 meters, the same as OM4.

The reason is that OM5 fiber does not perform better than OM4 at the wavelengths used by BiDi modules. In fact, OM4 Signature Core has outperformed standard OM5 fiber in multiple head-to-head tests at end users.

If the decision is to use 100G SWDM shortwave wavelength division multiplexing optical modules, and you need to transmit distances beyond 150 meters, then it is better to use our OM5 Signature Core MMF. The OM5 Signature Core MMF uses the same enhanced range technology as the OM4 Signature Core, so you can take advantage of this 20% longer range than the standard.