Which dispersion is a combination of material and waveguide dispersion and affects single-mode fiber?

Which dispersion is a combination of material and waveguide dispersion and affects single-mode fiber?

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

Answer: (C)

Chromatic dispersion is the overall spreading of a light pulse caused by how different wavelengths travel at different speeds in the fiber. This comes from two sources working together: the material dispersion, which is the glass’s refractive index changing with wavelength, and the waveguide dispersion, which arises from the fiber’s geometry and how the guided mode’s effective speed depends on wavelength. In a single-mode fiber, there isn’t a spread from different spatial paths (modal dispersion is negligible because there’s only one mode), so the total pulse broadening is dominated by the sum of material and waveguide dispersion. This combined effect—how both the material’s properties and the guiding structure influence speed across wavelengths—defines chromatic dispersion and sets the bandwidth limitations for single-mode fibers.

Chromatic dispersion is the overall spreading of a light pulse caused by how different wavelengths travel at different speeds in the fiber. This comes from two sources working together: the material dispersion, which is the glass’s refractive index changing with wavelength, and the waveguide dispersion, which arises from the fiber’s geometry and how the guided mode’s effective speed depends on wavelength. In a single-mode fiber, there isn’t a spread from different spatial paths (modal dispersion is negligible because there’s only one mode), so the total pulse broadening is dominated by the sum of material and waveguide dispersion. This combined effect—how both the material’s properties and the guiding structure influence speed across wavelengths—defines chromatic dispersion and sets the bandwidth limitations for single-mode fibers.