How does single-mode fiber differ from multi-mode fiber?

Single-mode fiber is designed to carry light directly down the fiber without allowing the light to bounce off the walls, which results in only one mode of light traveling through the fiber. This is in contrast to multi-mode fiber, which has a larger core diameter and allows multiple modes of light to travel through it. The ability of single-mode fiber to transmit data in only one mode minimizes modal dispersion, allowing for greater distances and higher bandwidth capabilities. This makes single-mode fiber particularly effective for long-distance telecommunications and data transmission applications.

On the other hand, multi-mode fiber is more suited for shorter distances, typically within buildings or campuses, due to the dispersion of multiple light modes. Therefore, the fundamental differences in how each type of fiber transmits light underlines why the correct answer highlights the distinction in the number of light modes that each fiber type supports.