Spectra-Physics Tsunami - Start-Up; Shut down; Typical Set-Ups; Example 1: Synchronizing Pulses from Two LTC Tsunami Lasers

Lok-to-Clock Electronics
8-9
Start-up
In addition to the normal start-up procedures outlined in Chapter 7, “Oper-
ation,” the following are general procedures to observe whenever using the
Model 3930 Lok-to-Clock electronics module.
1. Turn on the Model 3930 and allow it to stabilize for at least two hours.
Once on, never turn it off except to move it to a new location.
2. Mode lock the Tsunami laser and verify output performance (i.e. out-
put power, bandwidth, pulse width, etc. should meet published specifi-
cations).
You can monitor the external or internal reference signal frequency by
monitoring the REF OUT signal. Set the panel view mode to REF using
the SELECT button.
3. Verify the photodiode
LEVEL indicator on the front panel is fully lit.
The
LEVEL control should be fully clockwise.
4. Press the SELECT button to set the panel view to LSR to monitor the
laser repetition frequency and to verify it is stable. If it is not stable,
verify the Tsunami laser is operating correctly.
5. Press the LOCK button to lock the system (if DIF is < 50 kHz)
*
.
Shut Down
As a general procedure, unlock the system before turning off the laser.
However, leave the Model 3930 powered on when the system is not in use
in order to minimize frequency drift during the next start-up.
Typical Set-ups
Example 1: Synchronizing Pulses from
Two LTC Tsunami Lasers
A typical experiment set-up is shown in Figure 8-6. Tsunami “A” is the
master oscillator, and the 80 MHz REF OUT from its Model 3930 Lok-to-
Clock electronics module is used for the Model 3930
REF IN signal of Tsu-
nami “B.” The output beams of both lasers are combined and overlapped as
shown in the figure.
In an experiment using synchronized pulses from two
LTC Tsunami lasers,
the timing function (using either the manual
TIMING controls or the sweep
generator) facilitates locating your pulses by adjusting the timing of one
pulse with respect to the other. Use the sweep to find the pulses and the
TIMING controls to overlap them. Note: modifying the laser frequency by
50 Hz is equal to about 1 µm of motion at mirror M
1
.
*
If the frequency is > 50 kHz, use the up/down buttons to bring it within range.
Always unlock the system before tuning to a new wavelength, then opti-
mize the Tsunami output and lock it again.
Caution!