26
NanoTrak Autoalignment Controller
3.10.3 Using Two NanoTraks in the Same System
The NanoTrak scanning process uses a single frequency (and a highly selective
discriminator similar to a radio receiver) and it is possible to use more than one
NanoTrak controller in a single optical path (and with a single detector). For example,
with two control units set to different scanning frequencies (e.g.30 Hz and 40 Hz) it is
possible to couple fibers both into (master NanoTrak) and out of (slave NanoTrak) an
integrated optical device such as a waveguide – see Fig. 3.11. The scan frequency
and input source can be set either via the application software
(see Kinesis API
Helpfile)
or directly via the Settings panel – see Section 3.9.1.
To set up a two NanoTrak system:
1) Make connections as shown in Fig. 3.11.
2) Power up the NanoTrak units.
3) Run the software.
4) In the master NanoTrak GUI, select ‘Settings’.
5) Select the ‘Tracking’ tab, then set the Circle User Frequeny, e.g. 40 Hz.
6) Select the ‘Input/Output’ tab, then set the Input Signal Source to ‘PIN (TIA)’.
7) In the slave NanoTrak GUI, select ‘Settings’.
8) Select the ‘Tracking’ tab, then set the Circle User Frequency, e.g. 30 Hz.
9) Select the ‘Input/Output’ tab, then set the Input Signal Source to ‘BNC 10V’.
10)Set both NanoTraks to ‘Track’.
11)Once alignment is achieved, tracking can be verified. Move the axes of the
stage(s) by a small amount. The circle of the NanoTrak associated with the stage
should move accordingly to follow the signal.
If using the internal power meter, the detector output is connected to the OPTICAL/
PIN connector on the master unit and the signal to the slave NanoTrak must be routed
from the master SIG OUT to the slave SIG IN. If using an external power meter, a T-
splitter must be used on the SIG OUT connector of the master NanoTrak.
Note
A difference of at least 10Hz is recommended between this frequency and that set
at item (5). This is to ensure adequate frequency separation between the bandpass
filters of the two NanoTraks.
Note
With BNC input source is selected, the internal TIA circuit is bypassed and therefore
autoranging is not required. Also, the Tracking Indicator on the GUI panel is
inoperative.
