What type of fiber is typically used for high-bandwidth applications?

The correct choice is single-mode fiber, primarily because it is designed to carry signals over long distances with minimal loss and maximum bandwidth. Single-mode fibers have a smaller core diameter, typically around 8 to 10 microns, which allows only one mode of light to propagate through it. This characteristic minimizes modal dispersion, which can cause signal distortion over long distances. As a result, single-mode fibers can support higher bandwidth applications and greater distances compared to multimode fibers.

While multimode fiber can be used in high-bandwidth environments, especially within shorter distances, it is more susceptible to modal dispersion due to its larger core size (about 50 to 62.5 microns). This limits the maximum bandwidth and distance it can effectively transmit signals compared to single-mode fiber. Hence, for high-bandwidth applications requiring long-distance transmission, single-mode fiber is the superior option.