Toptica FemtoFiber pro IR, Manual, Page: 78 / 108

FemtoFiber
®
pro Laser System
Page 74
Status: 6.9.18
7 Piezo Voltage Indicator
showing the voltage applied to the piezo used to controll the phase difference.
8 Coarse Loop enable/disable Button
When enabled, the software controls an additional slow piezo motor whenever the fast piezo has
reached one of the given limits.
9 Manual Move Button
allows to manually move the piezo motor at any time.
10 Search Button
Pressing this button starts an automatic search alogrithm, trying to reduce the difference frequency
to zero in order to enable the PID 110 regulator to lock again.
11 Difference Frequency Indicator
whenever the PID 110 regulator falls out of lock, the data acquisition of the residual phase signal is
suspended and the difference frequency betwen the two RF frequencies is counted. In order to
enable the PID 110 to lock again it is necessary to move the piezo motor such that the frequency
difference is close to zero.
12 History Indicator of the difference frequency.
13,
14 RF Signal Level Indicator
giving the signal RF levels of the two inputs RF1 and RF2 in terms of dBm. In order for the phase
detector to work correctly the levels have to be in the range –10 dBm to –6 dBm. The indicators turn
red whenever one of the limits is exceeded, for too high signal levels additional an acoustic signal is
given.
15 Total Phase Offset Indicator
shows the total phase offset as given by the static software value plus the voltage level currently
applied to the Phase in (
∆Φ
in
) BNC-connector at the PHD 110 phase detector.
16 HV OK Indicator
indicating whether the high voltage supply for the piezo is correctly working.
17 Signal Level OK Indicator
indicating whether the RF input levels are within the required range, turning red whenever one of
the levels is out of bounds.
18 Phase Locked Indicator
indicating whether the measured jitter value is below a given maximum value.
19 Motor Busy Indicator
indicating whether the piezo motor is moving. Synchronously with this indicator the voltage level at
the Busy BNC output of the PHD 110 phase detector is changed. The busy and the idle voltage level
of the output can be user defined.
20 Flip Flop Indicator
A fast flip-flop in the phase detector is recognizing whenever the residual phase difference
exceeds a given maximum value, the flip-flop remembers such an event until it is reset by pressing
the „R“ button right of the indicator. The flip-flop assures that all „out of bounds“ events are
recognized by the user even if they are too fast for the software’s sampling rate.
21 Static Phase Offset Control
the phase offset between RF1 and RF2 can – within a certain range – be controlled by the software
and/or the Phase in (
∆Φ
in
) BNC-connector at the PHD 110 phase detector. This control allows to
enter a static (DC) phase offset of –250 ps to +250 ps (offsets are entered in units of seconds, while
„1e-12“ and „1p“ are, e.g., valid entries for 1 picosecond).
22 Analysis enable/disable Button
allows switching ON and OFF the data acquisition of the residual phase difference signal (diagrams
1 and 2), disabling the analysis improves the update rate of the other indicators as, e.g., the piezo
voltage. The data acquisition is automatically disabled whenever the PID 110 regulator falls out of
lock.