Hi Sindhu,
You only had one or two parameters off from a good simulation! The main issue here was the White Light Source, which was not centered at the correct frequency and the power was much too high (~36W) for the input signal. To fix it I set the center frequency of the white light to 450 nm, which is where your signal band is centered and I unchecked the PSD option and set the average power to 1 mW.
The technical background on the White Light source has more info on the PSD option, but basically when it is checked the power output will be the Power multiplied by the Sample rate. The background information can be found from the Help button on the component properties.
Regards