Step-index profile

A step-index profile is a type of refractive index distribution commonly used in optical fibers and waveguides. In this profile, the refractive index of the core (the central part of the fiber) has a uniform value and is significantly higher than that of the cladding (the outer layer surrounding the core). The transition between the core and the cladding occurs abruptly, creating a "step-like" change in the refractive index.