•
Start Vel.
: writing velocity in
µ
m/s at the beginning of the pattern.
•
End Vel.
: writing velocity in
µ
m/s at the end of the pattern.
•
Accel.
: acceleration in mm/s
2
use to change the writing velocity from Start Vel. to
End Vel. Along the FBG.
•
Step
: distance in
µ
m between points used to interpolate the Square Wave function.
Smaller the “step” distance, higher is number of points used for the function
interpolation.
•
AOM%
: laser output value (from 0 to 100%) used during the fabrication of the
FBG.
6.3.5 Uniform
A uniform FBG has even spacings between the grating planes and all the grating planes
are made using the same writing conditions. To create a file for the fabrication of uniform
FBGs, the Gaussian profile type is used. In this particular case, the Max and Min. values
for the laser output intensities must be chosen so to be identical. The example in Figure
33 illustrates how to use the Gaussian profile type to create a Uniform FBG pattern. The
Step Size is chosen to be 50 um, while the Min. and Max. values for the laser output
emission are both 100%. As expected, a straight line 5mm long is constructed.
Figure 33. Example of a profile used in the design of a uFAB file for the fabrication of a Uniform FBG.
6.3
“Run” Window
