Nutsinee Terry Daniel

OPO locking:

• With the ISI no longer locked the ~1kHz acoustic peak is a factor of a few lower and the OPO locking needs correspondingly less range. The lock also looks much better now.
• We copied the guardian from the SHG and updated it for the OPO. It seems to work.
• The power coupled through the fiber was increased by a few. We get just under 6mW onto the OPO REFL diode.
• OPO REFL Photodiode DC: Unlocked 5.8mW, Locked 2.2mW. The dip in reflection therefore is 62%

Fibers:

• We tried the waveplates in the green pump path and we are able to go as low as 0.7mW for the rejected light. The adjustment was somewhat cumbersome, since both waveplates needed to be rotated simultaneously to make further improvements towards the end.
• We also tried the manual waveplates in the seed path. We were able to get the rejected light up and down by about a factor of 4. It seems difficult to do better by hand.

Translation stage:

• We were able to move the lens translation stage using the PI controller.
• We didn't try the oven translation stage since we had no feedback, if it is moving.

Next:

• We need to realign the pick-off beam towards the homodyne detector,
• and find the red/green double resonance in the OPO.