Which dispersion type increases with core size and is a primary factor in multimode fibers?

Which dispersion type increases with core size and is a primary factor in multimode fibers?

• A. Material dispersion
• B. Waveguide dispersion
• C. Modal dispersion
• D. Chromatic dispersion

Answer: (C)

Modal dispersion is the dispersion mechanism that matters most in multimode fibers. In these fibers, light can travel through many different spatial modes, and each mode has a slightly different propagation speed and path length. As the core size grows, more modes become available, increasing the spread in arrival times of the light at the far end. That broadening manifests as pulse spreading, which directly limits bandwidth in multimode links. Material dispersion would stay the same regardless of core size, and while waveguide dispersion depends on the fiber's structure, the characteristic increase with core size and the primary role in multimode systems point to modal dispersion as the best explanation.

Modal dispersion is the dispersion mechanism that matters most in multimode fibers. In these fibers, light can travel through many different spatial modes, and each mode has a slightly different propagation speed and path length. As the core size grows, more modes become available, increasing the spread in arrival times of the light at the far end. That broadening manifests as pulse spreading, which directly limits bandwidth in multimode links. Material dispersion would stay the same regardless of core size, and while waveguide dispersion depends on the fiber's structure, the characteristic increase with core size and the primary role in multimode systems point to modal dispersion as the best explanation.