[Shalika, Marc]
Objective: Recover PLL alignment
Details:
1. We tuned the mirror alignment to increase the main laser and auxiliary laser coupling. For AUX1 and AUX2 the mirrors circled in red and blue in Fig 1 were tuned respectively. (The output of the PD was observed in the oscilloscope but it was fluctuating a lot and so the tuning was done with all lights off)
2. The coupling status is as follows
| Incident Power(mW) | Transmitted Power (mW) |
Coupling [NEW] (Transmitted x 2 / Incident) |
Reference value from 1200 | Reference value from FC page | |
| ML-AUX1 | 3.92 | 0.51 | 26% | 33% | 27% |
| ML-AUX2 | 4.87 | 0.76 | 31.2% | 31% | 31% |
| CC | 0.49 | 0.13 | 53.1% | 30% | 30% |
| P POL | 4.97 | 1.5 | 60.4% | 55% | 55% |
3. We did face trouble during tuning optics for AUX1. One possibility could be that after we changed EOM in the main laser path, the new EOM introduced a change in beam shape due to its wedge shape, and now it's difficult to focus the beam into the fiber.
4. Also, HWP was kept before mirrors (circled in red in Fig1) to investigate polarization issues. The effect of its rotation was not observed at the AUX1 output and left the output unchanged.
Next Step:
1. Soldering the amplifiers for the DDS3 board and doing connections.
