FiberLock Manual
2.4.1 Optimization of all Parameters
Fiber coupling depends on a number of alignment parameters, for example the angle at which the
laser enters the fiber, the position of the fiber aperture and the focus position along the axis of
the fiber. In a typical optical setup, these parameters are not independent of each other: Changing
the focus can hardly be done without affecting the position of the fiber aperture, a change of
the horizontal beam angle typically also affects the vertical angle, etc. This makes the manual
optimization of all involved degrees of freedom very difficult and time-consuming.
Although the FiberLock only locks two degrees of freedom (say the horizontal and vertical beam
position), this greatly simplifies the manual optimization of the remaining parameters. The focus
position, for example, can now be changed without worrying about affecting the beam position,
since this will be automatically adjusted by the FiberLock. If the gain of the position regulator is
well adjusted, all other degrees of freedom of the fiber coupling can be manually adjusted in a fast
and simple manner without ever losing the lock.
2.5 Search Function
The search function can be triggered from within the software or by pressing and holding the button
on the front panel. The FiberLock will start to scan over the fiber aperture and automatically lock
on to the found intensity peak. This functionality is very useful when the coupling has been lost,
for example by manual misalignment of the optical elements. As long as the misalignment is small
(within the scan range of the actuator), the search function will re-lock within seconds.
2.6 Saving Settings
Any parameter changes are lost as soon as the FiberLock loses power or resets. In order to make
changes permanent, the dialed settings must be committed to the microcontroller’s non-volatile
memory. This is achieved with the “VarSave” button in the Kangoo interface. To change saved
settings, simply overwrite them by changing some parameters and pressing “VarSave” again. At the
next system start, these saved settings will be loaded and used as default parameter. An exception
to this is the started of the regulator, which is always off at start-up.
2.7 Operation Without PC
While it is useful to connect the FiberLock to a PC for visualization and for setting parameters, the
device can work on its own and is indeed intended to do so for every-day operation. The following
description of the front and real panel elements shows how to operate the FiberLock without a PC.
FiberLock Manual
July 26, 2021 9 / 21
