In today’s rapidly evolving network infrastructure landscape, telecom operators and data center providers face a constant balancing act between performance, distance, and cost. The demand for higher bandwidth over longer distances continues to grow, driven by applications like cloud computing, content delivery, and real-time services. This is where the 100G ER4 transceiver finds its sweet spot—providing a cost-effective, scalable solution that straddles both metro and long-haul optical transport.
What is 100G ER4
The 100G ER4 (Extended Reach) optical transceiver is designed to support 100 Gigabit Ethernet transmission over single-mode fiber (SMF) with a reach of up to 40 kilometers. It operates on four CWDM (Coarse Wavelength Division Multiplexing) channels with wavelengths ranging from 1295 nm to 1310 nm and uses a duplex LC connector interface. This module typically adopts the QSFP28 form factor and utilizes EML (Electro-absorption Modulated Laser) transmitters combined with SOA (Semiconductor Optical Amplifier) receivers for enhanced long-distance performance.
The Metro-Long-Haul Challenge
Traditionally, network planners had to choose between metro optics, which are cost-efficient but limited in range, and long-haul coherent optics, which offer extended reach but at a much higher cost and power consumption. Metro networks usually span between 10 km to 40 km, while long-haul links can extend to hundreds of kilometers. Bridging these use cases effectively without overbuilding or overspending requires a versatile solution—and 100G ER4 delivers exactly that.
Cost-Effective Reach Without Coherent Complexity
One of the most significant advantages of 100G ER4 modules is their ability to cover distances up to 40 km without the need for complex and expensive coherent optical systems. This makes them ideal for metro aggregation, data center interconnect (DCI), and even some short long-haul applications. Unlike coherent modules that require digital signal processors (DSPs) and consume more power, ER4 transceivers offer a simpler plug-and-play solution with power consumption typically under 5W.
For service providers upgrading their infrastructure from 10G to 100G, ER4 allows for easy scaling without the need for major architectural changes or investment in amplified links and dispersion compensation modules. It also provides the flexibility to gradually expand to longer distances as needed, making it a future-proof investment.
Application Scenarios
Metro Aggregation: ER4 can be used to aggregate traffic from multiple access nodes to core routers or data centers.
Data Center Interconnect (DCI): Perfect for interconnecting facilities within a metro area where the distance exceeds 10 km but is less than 40 km.
Disaster Recovery Links: Provides a reliable and redundant 100G link between geographically separated data centers.
Cloud and CDN Backbone Expansion: Supports scalable bandwidth between CDN edge locations and cloud regions without relying on costly coherent optics.
Conclusion
The 100G ER4 optical transceiver proves that network upgrades don’t always require a trade-off between performance and budget. With its extended reach, high compatibility, and lower cost compared to coherent modules, it effectively bridges the gap between metro and long-haul applications. For network operators looking to streamline their infrastructure while meeting future traffic demands, 100G ER4 is a smart, future-ready solution.