We are checking the noise contribution from electronics readout of our system to get better noise budget estimation. We added detection noise from RCAV and ACAV systems in the noise budget. They are comparable to the estimated shot noise level.
We measured the noise level of the PDH detection for RCAV and ACAV system, the corresponding error signal slope.The results are summarized in the table below.
Setup: 1mW input to each cavity, TTFSS: Common/Fast = 900/800,
| |
RCAV |
ACAV |
| Pwr input [mW] |
1 |
1 |
| V_DC (RFL RFPD) [V] |
1.7 |
1.47 |
| Err signal Slope [kHz/V] |
40.3 |
81.7 |
| Detection Noise [nV/rtHz] |
35 |
23 |
Detection Noise x Err signal slope gives us the electronic noise contribution in absolute frequency unit. From the above table, we obtain
1 mHz/rtHz and 1.8 mHz/rtHz from RCAV and ACAV systems, respectively.
The electronic noise from RCAV and ACAV systems are added to the noise budget. In the plot below, I removed the traces for Spacer noise and thermo optic noise to make the plot less crowded, but their contribution are included in the total noise.
More to come:
- Shot noise measurement for ACAV/RCAV/beat
- TTFSS OLG TF, suppressed laser frequency noise
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