Fibers can be classified into two main modes of propagation: single-mode fibers and multi-mode fibers. Single-mode fibers have a small core diameter, which allows only one mode of light to propagate through the fiber. This results in low dispersion and higher bandwidth, making single-mode fibers suitable for long-distance, high-speed communication applications. Multi-mode fibers have a larger core diameter, which allows multiple modes of light to propagate through the fiber. This results in higher dispersion and lower bandwidth, making multi-mode fibers more suitable for short-distance, lower-speed communication applications.