Which type of fiber travels further, Multimode or Single-Mode?

Single-Mode fiber is designed to carry light over longer distances compared to Multimode fiber. This capability is rooted in the physical construction of the fibers. Single-Mode fiber features a smaller core diameter, typically around 8 to 10 microns, which allows a single light mode to propagate through the fiber. This design minimizes the light reflections and modal dispersion that can occur in multimode fibers, where the core is larger (about 50 or 62.5 microns) and supports multiple light modes traveling at different speeds.

As a result, Single-Mode fiber can effectively transmit signals over several kilometers—often exceeding 40 kilometers in long-haul telecommunications—while Multimode fiber is usually limited to shorter distances, generally up to 400 meters or less, depending on the specific type of Multimode fiber and the equipment used.

This inherent difference in distance capabilities between Single-Mode and Multimode fibers makes Single-Mode the preferable choice for long-distance telecommunications and data center interconnections, allowing for the efficient transfer of data over vast networks.