Dear Mohanachandran,
You may use OptiGrating to design your grating, then load the emission and transmission spectra to OptiSystem to conduct transmission simulation using
OptiGrating component located at Default/Optiwave Software Tools/
You may use the FBG Sensor component or Uniform FBG Sensor components located at Default/Sensors/ to design your FBG and use the strain effect and simulation the shift versus strain.
Regards,
Ahmad