Multimode transceivers (devices that have a transmitter and a receiver that share some of the circuitry or are located in the same box), for example, have a much lower cost than single-mode technology equipment, which is mainly used by telecommunications operators in optical connections with a few kilometers of distance.

In data centers, where transmission distances are shorter, multimode fiber becomes the most appropriate option from both an economic and management standpoint. Currently, 10 Gbps interfaces are the most widely used in the market, but migration to the newer 25 Gbps, 40 Gbps, and 100 Gbps speeds is underway.

But what will happen in the near future, when equipment for systems with speeds of 200 Gbps and 400 Gbps becomes available on the market? These new speeds have recently been standardized through IEEE 802.3bs (Standard for Ethernet Amendment: Media Access Control Parameters, Physical Layers and Management Parameters for 200 Gb/s and 400 Gb/s Operation). However, what is the appropriate solution for implementing 200 Gbps and 400 Gbps systems using multimode optical fibers?

The answer to these concerns comes thanks to the new OM5 category multimode fibers, which are compatible with various wavelengths, offering a new transmission mode that reflects a large reduction in the infrastructure of data centers.

Thanks to the Telecommunications Industry Association's (TIA) update to the 492AAAE data center cabling standard, it was previously impossible to transmit multiple wavelengths over multimode fiber. The only way to achieve this was by creating parallel transmissions using MPO connectors.

Currently, with the new OM5 multimode fibers, up to four wavelengths, between 850nm and 950nm, can be used. This capability is enabled by SWDM (Shortwave Wavelength Division Multiplexing) technology, which offers a new transmission mode with multimode optical fibers.

This concept is equivalent to DWDM (Dense Wavelength Division Multiplexing) for single-mode optical fibers. The difference is that SWDM uses wavelengths of 850nm, 880nm, 910nm, and 940nm.

 

With the increased capacity of OM5 fiber, transmissions of 40 Gbps or 100 Gbps can be achieved over a single fiber pair, using different wavelengths (850 nm, 880 nm, 910 nm, and 940 nm). For example, a 100GBASE-SWDM4 application can perform four 25 Gbps transmissions over one fiber pair, at different wavelengths. This translates to a fourfold reduction in the number of optical fibers required, less infrastructure usage, and greater ease of management.   

In the future, speeds of 200 Gbps and 400 Gbps will also be achievable with transmissions over a single pair of optical fibers. Undoubtedly, SWDM technology over OM5 optical fibers opens new possibilities for the use of 40G, 100G, 200G, and 400G applications, with better utilization of infrastructure and equipment, and optimized space in data centers. And OM5 optical fiber confirms the trend of increasing transmission capacity for multimode fibers.