What unit is used to measure fiber size?

The unit used to measure fiber size is microns, commonly represented as "um." This measurement indicates the diameter of the fiber optic core, which is crucial for determining the type of fiber—single-mode or multimode—as well as its performance characteristics.

Single-mode fibers typically have a core diameter of about 8 to 10 microns, while multimode fibers usually range from 50 to 62.5 microns in core diameter. Understanding fiber size is integral to fiber optic technology since the core's diameter impacts the light transmission and bandwidth capacity of the fiber.

The other units listed—nanometers, decibels, and megahertz—are utilized for different purposes in the field of optics and telecommunications. Nanometers are used to measure wavelength, decibels measure signal loss or gain, and megahertz is often related to bandwidth and frequency of signals, but none of these directly measures the fiber size.