What distinguishes single mode fiber from multimode fiber?

The distinguishing characteristic of single mode fiber is its smaller core diameter compared to multimode fiber, which allows it to transmit light signals over much longer distances. The small core, typically around 8 to 10 micrometers in diameter, permits only a single mode of light to propagate. This results in significantly reduced modal dispersion, making single mode fiber ideal for long-distance communication applications.

In contrast, multimode fiber has a larger core diameter, usually around 50 to 62.5 micrometers, which permits multiple light modes to travel simultaneously. While this allows for higher bandwidth over shorter distances, it also leads to greater modal dispersion and limits the effective distance over which the signals can be transmitted without significant loss.

Thus, the small core diameter of single mode fiber, combined with its ability to transmit over longer distances, sets it apart from multimode fiber and makes it the preferred choice for extensive telecommunication networks.