Maximum transmission distance of 100G optical module

100G optical modules support transmission distances ranging from a few meters to 80 kilometers, depending on the module type and fiber used.

Short-Distance Modules

For intra-data center connections, short-range modules like 100G SR4 or Active Optical Cables (AOC) are commonly used. SR4 modules typically operate over multimode fiber and support distances up to 100–150 meters depending on fiber type (OM3, OM4, OM5) and wavelength (850–940nm) . DACs are suitable for very short connections, generally up to 7 meters, while AOCs can extend up to 30 meters .

Medium-Distance Modules

For inter-rack or campus networks, medium-range modules such as 100G CWDM4 and 100G LR4 are used. CWDM4 modules use coarse wavelength division multiplexing over single-mode fiber and typically support distances up to 2 km . LR4 modules operate at 1310nm over single-mode fiber and can reach 10 km, making them suitable for metropolitan area networks or connections between nearby data centers .

Long-Distance Modules

For long-haul or carrier-grade networks, modules like 100G ER4, 100G BiDi, and 100G BIDI 80KM are designed for extended reach. ER4 modules can transmit up to 40 km over single-mode fiber with FEC enabled . Advanced BiDi modules can achieve 80 km without relays, using high-power DFB lasers, dispersion compensation, and low-noise APD detectors, making them ideal for inter-city links, 5G backhaul, and backbone networks . Some specialized modules, such as 100G ZR, can extend even further for ultra-long-haul applications.

Key Considerations

• Fiber Type: Multimode fiber limits short-range modules, while single-mode fiber enables long-distance transmission.
• Wavelength: Modules operate at different wavelengths (850nm, 1310nm, 1550nm) affecting reach and compatibility.
• FEC and Dispersion Compensation: Enabling FEC and using modules with built-in dispersion compensation can significantly extend transmission distance.
• Application Scenario: Short-range modules are cost-effective for data centers, while long-range modules are optimized for DCI, telecom backbones, and 5G networks . In summary, 100G optical modules cover a wide range of transmission distances: from meters in data centers to tens of kilometers for metro networks, and up to 80 km or more for long-haul links, depending on the module type, fiber, and network requirements.