GPX3800 and GPX3850 Glass Processors
Chapter 5: Operation
Rev B, July 24, 2018
Page 35
This tapering process is in fact similar to a fiber drawing process, where the pre-form enters the furnace at a slow
velocity and is pulled at a higher rate, inducing the smaller diameter fiber. The control of the diameters is achieved
by a precise control of both feed and pull velocities along the process. The next tab in the Taper Properties
window lets the user control the gas flow, the character of the pulling, and the filament power. It is shown in
Figure 16.
Figure 16
Editing Taper Parameters
Here are some notes regarding the values in the “Taper Parameters” window.
Furnace Offset:
This will offset the filament to a desired location for the start of the taper.
Filament Start:
This is the power that the filament will initially be set to when the taper is
to begin.
Filament Delta:
This is the percentage of reduction (negative value) or increase (positive
value) in the filament power along the taper process. The power varies
from P at the beginning of the “down taper” to P ± Δ at the beginning of
the waist and then varies back from P ± Δ at the end of the waist to P at
the end of the “up taper”
Filament Delay:
This is the amount of time the filament is on before beginning the
tapering process.
Gas Flow Rate:
This is the flow rate of the argon during the actual tapering process
.
Post-Purge Time:
This is the amount of time spent flowing the argon at the higher rate after
a taper has been pulled.
Pre-Purge Time:
This is the amount of time spent flowing the argon at the higher rate
before a taper is pulled.
Pull Velocity:
This is the constant speed at which the fiber is feed through the filament
at the beginning of the tapering process.
Time Constant:
The time constant is the time interval at which the software calculates the
velocities to apply to the system in order to achieve the correct taper.
The default value is 0.1 s.
Furnace Move:
This allows the filament to move during the taper process.