[Sugimoto, Enomoto]
(See also 5346 and its comments)

= Summary =
We measured the phase (frequency) noise of the G&H AOM driver, which will be used for green AOM, by phase-locking the driver to a more stable oscillator, Agilent N5181B.
The results can be found in the first attached figure.
The frequency noise seems to high in low frequency so we definitely need some changes on the driver in order to have a good ALS.

= How we measured =
The second attached shows the block diagram of the PLL we performed.
Since the UGF was high enough (~ 100 kHz), we measured the power spectral density of the control signal to evaluate the frequency noise.
The actuator efficiency (volt --> freq) of the driver was measured in a separate measurement as shown in the third attached figure. The result is consistent with one we got before (5351).
We confirmed that electrical noises were far below the measured noise.
NOTE: We assumed we saved the PSD we got to a floppy disk, but the saved files were lost somehow. So sad.
What we have is only pictures of the display of the spectrum analyzer, so I "reconstructed" the PSD data from the picture to some extent. So sad. (For these pictures see 5406)
I think the error caused by doing this is within 2 dB.

= Next thing =
-- Do noise budget with this noise data
-- Consider seriously how to obtain a more stable VCO (buy a different VCO and do frequency divide?)