Tsunami - Beckman Institute Laser Resource Center

Lok-to-Clock Electronics
Installing the Model 3930
CAUTION
Do not connect the BNC cable from the PHOTODIODE IN connector to
the ML PD connector on the laser head. The photodiode signals from ML
PD and LTC PD are calibrated differently and ML PD will over-drive the
PHOTODIODE IN connector if swapped.
REF IN connector-provides connection for either a user-defined external
reference signal (defined at time of purchase) or the 80 MHz internal
reference signal. When the internal reference is used, a BNC cable
connects from the 80 MHz OUT connector to this connector (Figure 8-4).
An input rf signal of between 76 and 83 MHz can be accepted provided
the laser cavity length has been factory preset. Input impedance is 50 Q at
0 dBm for a sine wave.
REF OUT connector-provides a buffered signal from the selected reference
input signal for use with an external frequency counter or other user
equipment. Output impedance is 50 Q at 0 dBm for a sine wave.
REF + 8 connector-provides a buffered 8:l frequency-divided signal
from the selected reference input signal for use with an external frequency
counter or other user equipment. When the internal reference is used,
output is 10 MHz. Output impedance is 50 Q at 0 dBm for a sine wave.
80 MHz OUT connector-provides a buffered 80 MHz sine wave signal
from the internal reference source. It can be used for the REF IN reference
input signal in lieu of an external, user-supplied signal. Output impedance
is 50 Q at 0 dBm for a sine wave.
Note: you must have a Model 3960C or D or a 39506 or D version
Tsunami laser head to use this system.
The Model 3930 is easy to install. Merely install the PZT M4 mirror in the
Tsunami laser head and connect the BNC and ribbon cables between the
LTC electronics module and the laser head. There may be other connections
depending on the requirements of the experiment or lab setup (for
oscilloscope, external photodiode, etc.). The following procedure covers
most standard installations and assumes the Tsunami laser is properly
aligned according to chapter 6, "Alignment," and running. according to
chapter 7, "Operation."
1. Place the Model 3955 electronics module on top of the Tsunami
Model 3930 module. Both modules should be within 1 m of the
Tsunami laser head.
2. Attach the 25-pin ribbon connector (from the accessory kit) between
the TO HEAD connector on the rear panel of the Model 3930 and the TO
3930 female connector on the input bezel of the Tsunami laser head.
3. Disconnect the 50 Q terminator on the LTC PD connector and place it
in the tool kit.