Definition: multimode fiber

An optical fiber with a larger core than singlemode fiber. It is the most commonly used fiber for short distances such as LANs. Light can enter the core at different angles, making it easier to connect the light source to broader light sources such as LEDs. However, light rays travel down multiple reflective paths (modes) in multimode fiber, causing modal dispersion, which is a broadening of the pulses at the receiving end. Contrast with singlemode fiber. See graded-index fiber, dispersion and fiber optics glossary.