Which dispersion type affects multimode fiber and is directly related to the larger core size?

Which dispersion type affects multimode fiber and is directly related to the larger core size?

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

Answer: (C)

Modal dispersion is the spreading of a light pulse in a multimode fiber caused by different propagation paths. In multimode fibers, many modes travel simultaneously, each following a distinct route and arriving at the end at different times. A larger core supports more modes, increasing the range of possible paths and the differences in travel times, which broadens the pulse. Because this effect arises from the geometry and the number of supported modes, it is directly tied to the core size. Material dispersion comes from the glass’s refractive index changing with wavelength, so it affects all modes similarly and isn’t about core size. Chromatic dispersion is the overall dispersion combining material and waveguide effects. Waveguide dispersion depends on how the fiber’s structure influences velocity with wavelength, not primarily on the presence of multiple modes in a larger core.

Modal dispersion is the spreading of a light pulse in a multimode fiber caused by different propagation paths. In multimode fibers, many modes travel simultaneously, each following a distinct route and arriving at the end at different times. A larger core supports more modes, increasing the range of possible paths and the differences in travel times, which broadens the pulse. Because this effect arises from the geometry and the number of supported modes, it is directly tied to the core size.

Material dispersion comes from the glass’s refractive index changing with wavelength, so it affects all modes similarly and isn’t about core size. Chromatic dispersion is the overall dispersion combining material and waveguide effects. Waveguide dispersion depends on how the fiber’s structure influences velocity with wavelength, not primarily on the presence of multiple modes in a larger core.