Which type of optical fiber is best suited for high speed and long distance applications?

Single-mode optical fiber is best suited for high-speed and long-distance applications due to its design, which allows light to travel straight down the fiber without much reflection. This minimizes signal loss and maintains signal integrity over long distances, making it ideal for telecommunications and internet infrastructure that requires efficient, high-bandwidth data transmission.

In single-mode fibers, the core diameter is very small, typically around 8 to 10 micrometers, which only allows a single mode of light to propagate. This reduces modal dispersion—an effect that can lead to signal degradation—compared to multi-mode fibers, which have larger cores and support multiple light modes. As a result, single-mode fibers can efficiently transmit data over kilometers with light sources like lasers, which are capable of producing the coherent light necessary for effective long-distance transmission.

In contrast, multi-mode fibers are generally used for shorter distances due to their larger core size, which leads to greater modal dispersion and limits the bandwidth over longer runs. Graded-index fibers attempt to mitigate some of the dispersion in multi-mode fibers but still face limitations when it comes to high-speed and long-distance applications. Hybrid fibers combine features of both single-mode and multi-mode fibers, but they do not specifically excel in either of the two categories