8
ISOMET
4.7
With an insulated alignment tool or screwdriver rotate the PWR ADJ potentiometer fully anti-
clockwise (CCW) , then clockwise (CW) approx 1/4 turn.
4.8
Apply DC to the amplifier.
4.9
Apply a 10.0V constant signal to the Analog modulation input on the D-type connector.
Connect pin 8 of ‘D’ to the signal and pin 9 of ‘D’ to the signal return.
4.10
Apply a constant TTL high level to the digital Gate input on the D-type connector.
Connect pin 6 of the ‘D’ to the signal and pin 7 of the ‘D’ to the signal return.
Input the laser beam toward the centre of either aperture of the AOM. Ensure the polarization is
vertical with respect to the base and the beam height does not exceed the active aperture height of
the AOM.
Start with the laser beam normal to the input optical face of the AOM and very slowly rotate the AOM
(either direction). See Figure 4 below for one possible configuration.
4.11
Observe the diffracted first-order output from the acousto-optic modulator and the undeflected
zeroth order beam. Adjust the Bragg angle (rotate the modulator) to maximise first order
beam intensity.
4.12
After Bragg angle has been optimized, slowly increase the RF power (rotate PWR ADJ CW)
until maximum first order intensity is obtained.
4.13
The driver is now ready for use for modulation using both the digital and the analog inputs.