L. R. Chen et. al., ‘Ultrashort pulse reflection from fiber gratings: A numerical
investigation,’ J. Lightwave Technol., vol.15, No.8, (1997), pp.1505-1512.
The example demonstrates a transform-limited Gaussian pulse reflected from
apodized fiber gratings. The gratings are apodized by a Gaussian function and the
same index modulation value of 4.356e-4.
You can change the average index option and compare the results with the published
reference as follows:
- User Defined Average Index: Index_Mod*exp(-(2*(x-Length/2)/0.5/Length)^2). Click the Calculation button and compare the result (Pict 1) with the type A profile of Fig 5(b) from the Reference.
- Uniform Average Index with Index Change 0. Click the Calculation button and compare the result (Pict 2) with the type B profile of Fig 5(b) from the Reference.
The main result is reshaping of the reflected pulse. The structure of the reflected pulse
from the type B grating profile contains considerable regular oscillations, not present
in the type A profile.