Hello Mahalakshmi,
In OptiFiber you design your fiber by specify the refractive index and width of each region. Regions are concentric layers staring from the center or fiber core at r=0.
You can specify the refractive index or the doping concentration of the regions by selecting the refractive index profile or dopant concentration distribution option respectively.
You can verify and check the RI profile in the “profile” tab and can readily measure/trace the RI profile graph.
Kind regards,
Amin