What factor limits the maximum length of multimode fiber cables?

The maximum length of multimode fiber cables is primarily limited by light dispersion. This phenomenon occurs because multimode fiber has a larger core diameter compared to single-mode fiber, allowing multiple light modes to propagate through the fiber. As these modes travel, they take different paths and arrive at the destination at slightly different times, which can cause the light signal to spread out or disperse over distance.

This dispersion can lead to signal degradation and limits the effective transmission distance of multimode fibers. Specifically, the different arrival times of the light pulses can result in overlapping signals, making it difficult for the receiving equipment to distinguish between them. Consequently, the longer the fiber run, the more significant the impact of dispersion, which ultimately restricts the maximum length over which multimode fiber can reliably transmit data without significant loss of signal quality.

Other factors like core diameter, while relevant to the performance characteristics of the fiber, do not directly limit distance in the same way dispersion does. Cost and installation difficulty, although important considerations for deployment, are not technical limitations that affect the transmission distance itself.