How does the refractive index profile differ between graded-index and step-index multi-mode fiber, and what is the impact on signal propagation?

The key difference between graded-index and step-index multi-mode fiber lies in their refractive index profile, which significantly impacts signal propagation. The refractive index is a measure of how much light bends when it passes from one medium to another. Step-index multi-mode fiber has a core with a uniform refractive index. This means the refractive index is constant throughout the entire core and then abruptly changes at the boundary between the core and the cladding, creating a "step." Light traveling through step-index fiber reflects off the core-cladding boundar....