40/100G Multi-mode Fiber Solutions for Data Center Network
Jun 30, 20251 min read
As data centers evolve toward 200G, 400G, and even 800G infrastructures, many organizations are still upgrading their backbone from 10G to 40G or 100G. To ensure a smooth and cost-effective transition, it's critical to deploy multimode fiber solutions that offer high scalability, simplify cabling complexity, and minimize infrastructure disruptions. Structured cabling, parallel optics, and WDM (Wavelength Division Multiplexing) technologies—such as SWDM and BiDi—enable enterprises to extend current fiber assets while preparing for future network demands. This article explores key deployment considerations and practical solutions for building reliable and scalable 40/100G data center fiber connectivity.
Key Considerations for 40/100G Network Upgrades
The transition to 40G/100G networks involves more than just speed upgrades—it requires careful planning of fiber infrastructure. Two major factors should be evaluated:
Link Distance and Power Loss Amount
Although most data center links are short, cumulative insertion loss from patch panels, connectors, and splicing points can significantly impact performance. As network density increases, managing the optical power budget becomes critical. Deploying low-loss multimode fiber, along with technologies such as shortwave wavelength division multiplexing (SWDM), helps maintain signal integrity and extend transmission distance without requiring additional fibers.
Cabling Infrastructure Design
The TIA-942 standard provides guidelines for scalable data center cabling. A well-implemented structured cabling system based on 40/100G multimode fiber enables modular growth while reducing cable clutter and improving airflow. It also allows for flexible maintenance and upgrades, as only connectors may need replacement, without touching the backbone or horizontal cabling.
40/100G Multimode Fiber Connectivity Technology
To migrate from 10G to 40G/100G, two main technologies are used: parallel optics and WDM. Both support efficient multimode transmission, and the choice depends on the specific network design, fiber availability, and budget.
Parallel Optics Technology
Parallel optics technology transmits multiple data lanes simultaneously over several fibers. For example, 40GBASE-SR4 uses 8 fibers (4×10G Tx + 4×10G Rx). Earlier 100G implementations, like 100GBASE-SR10, required 20 fibers. With the advancement of VCSEL technology, modern 100GBASE-SR4 requires only 8 fibers (4×25G Tx + 4×25G Rx), reducing fiber count and simplifying installation while maintaining high throughput.
WDM Technology (SWDM & BiDi)
WDM allows multiple data channels to travel over a single fiber by transmitting different wavelengths. In multimode environments, the most common implementations are shortwave WDM (SWDM) and bidirectional (BiDi) transceivers.
SWDM utilizes four distinct wavelengths (typically from 850nm to 940nm) to deliver 40G or 100G Ethernet over standard LC OM3, OM4, or OM5 fibers. This eliminates the need for parallel fibers and extends the value of existing cabling. OM5 fiber, with optimized wideband support, enhances SWDM performance and allows longer reach. BiDi transceivers transmit and receive over a single fiber using two wavelengths in opposite directions. This approach cuts fiber usage in half and is ideal for space-constrained, high-density environments.
40/100G Multimode Fiber Cabling Connectivity Options
When designing data center fiber solutions, selecting the right cabling configuration ensures reliable, high-speed transmission. The tables below outline the maximum distances supported by multimode fiber in parallel optics and WDM-based deployments.
Parallel Optics Multimode Fiber Options
WDM-Based Multimode Fiber Options (BiDi/SWDM)
Data Rate | Interface Type | Fiber Mode | Wavelength | Maximum Distance |
40G | 40GBASE-BiDi | OM3 | 850nm | 100m |
OM4 | 850nm | 150m | ||
OM5 | 850nm | 200m | ||
40G-SWDM4 | OM3 | 850nm | 240m | |
OM4 | 850nm | 350m | ||
OM5 | 850nm | 440m | ||
100G | 100G-SWDM4 | OM3 | 850nm | 75m |
OM4 | 850nm | 100m | ||
OM5 | 850nm | 150m |
Conclusion
Upgrading to 40G or 100G is more than a hardware swap—it requires choosing the right multimode fiber solutions that balance performance, cost, and scalability. By adopting structured cabling and leveraging parallel optics, SWDM, and BiDi, data centers can simplify infrastructure and prepare for future demands. FS offers a full range of 40/100G multimode fiber products, including transceivers, patch cables, MTP®/MPO systems, and WDM modules, all optimized for high-density deployments. Visit FS.COM to accelerate your network upgrade with trusted solutions.