Which type of fiber optic cable is less suitable for long distances due to modal dispersion?

Modal dispersion is a phenomenon that occurs primarily in multi-mode fiber optic cables. This type of fiber has a larger core diameter, which allows multiple light modes (or paths) to propagate through the fiber. Each mode travels at a different speed; thus, the time it takes for the light to reach the end of the fiber can vary. As a result, when signals are transmitted over long distances, the differences in travel times can lead to signal spreading and degradation, making it less effective for long-distance communication.

Single-mode fiber, on the other hand, has a much smaller core, allowing only one mode of light to propagate. This reduces modal dispersion significantly, making it more suitable for long-distance applications. Plastic fiber, while more flexible and easier to handle, does not perform as well in terms of signal integrity over distances compared to glass fiber, but it is also less affected by modal dispersion than multi-mode fiber. Vapor-phase fiber is not a widely recognized term in the context of fiber optics and does not apply to this discussion.

Understanding the characteristics of different types of fiber optic cables is crucial for selecting the appropriate type for specific applications, especially when considering distance and the quality of signal transmission.