Hello Mahalakshmi,
The SMF components in OptiSystem don’t have input parameters for core/cladding refractive index or NA. However, MMF components do have that. The propagation models for SMF don’t need the linear refractive index. The MMF components needs these parameters for determining the number of modes. Please check the “Measured Multimode Fiber” component located at Default/Multimode Library/Optical Fibers/ for more information.
Regards,
Ahmad