Chromatic dispersion is a combination of which two types of dispersions?

Chromatic dispersion is indeed the result of the combination of material dispersion and waveguide dispersion.

Material dispersion occurs due to the variation of the refractive index of a material with wavelength. As light travels through a medium, different wavelengths will travel at different speeds. This causes a spread in the arrival times of different colors, leading to pulse broadening.

Waveguide dispersion, on the other hand, is related to how light propagates in a waveguide structure, such as an optical fiber. This form of dispersion arises due to the geometrical structure of the waveguide, which affects how different wavelengths are guided and how their group velocities differ.

The interaction between these two types ultimately leads to chromatic dispersion, resulting in bandwidth limitations for optical communication systems. Understanding chromatic dispersion is vital for designing fiber optic systems to ensure signal integrity over long distances.