Which type of fiber is most affected by modal dispersion?

The type of fiber most affected by modal dispersion is multi-mode fiber. In multi-mode fiber, multiple light paths or "modes" can travel through the fiber simultaneously. Each mode travels at a different speed due to varying path lengths, which can lead to overlapping signals as the light from each mode reaches the end of the fiber at different times. This phenomenon is known as modal dispersion, and it can limit the bandwidth and signal clarity over longer distances.

In contrast, single-mode fiber primarily allows only one mode of light to propagate, significantly reducing modal dispersion effects since all light travels along a single path. Plastic optical fiber and hybrid fiber can possess characteristics that mitigate modal dispersion, but multi-mode fiber is specifically designed for applications where multiple signals travel simultaneously, making it more susceptible to this issue. This is why multi-mode fiber is recognized as being most affected by modal dispersion.