In terms of light transmission, which fiber type effectively manages higher data rates over longer distances?

The correct answer is singlemode fiber, which is specifically designed to allow light to travel straight down the fiber's core with minimal modal dispersion. This characteristic enables singlemode fiber to manage higher data rates over longer distances compared to other fiber types. The small core diameter reduces the number of light paths (modes) that can be transmitted, which helps to mitigate the effects of dispersion that would otherwise limit the distance and data rates.

Singlemode fiber is particularly advantageous for telecommunications and data network applications, where long-distance transmission of high-speed signals is required. It can support very high bandwidths due to its ability to transmit light in a single mode, resulting in cleaner signals and improved performance over substantial distances, often exceeding several kilometers without the need for signal regeneration.

In contrast, multimode fiber, while useful for shorter distances in data centers and within a building, has a larger core that allows multiple light modes to propagate, leading to greater modal dispersion. This dispersion limits the effective transmission distance and data rates compared to singlemode fiber. Plastic optical fiber and graded index fiber also do not match the performance of singlemode fiber in terms of long-distance, high-data-rate capabilities.