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Entry  Fri Apr 30 12:07:25 2021, aaron, DailyProgress, Laser, marconi locking 252D9563-0122-418B-9B97-29D44FEF83E9.jpeg
    Reply  Fri Apr 30 15:15:33 2021, rana, DailyProgress, Laser, marconi locking 
       Reply  Mon May 3 23:28:56 2021, rana, DailyProgress, Laser, delay line frequency discriminator DFD.jpg
          Reply  Wed May 5 11:54:19 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 9x
             Reply  Wed May 5 22:21:17 2021, rana, DailyProgress, General, delay line frequency discriminator 
             Reply  Thu May 6 10:48:40 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 3EFFFA27-AAF6-434F-A1AB-FE7C657A464C.jpegDL_3CH.pdf
                Reply  Tue May 11 14:37:48 2021, aaron, DailyProgress, Laser, delay line frequency discriminator, current noise measurement 
                   Reply  Wed May 12 15:35:09 2021, aaron, DailyProgress, Laser, delay line in a box 69A8E6A2-7F85-464E-BDAA-8C6BBD2910B5.jpeg1D05A31E-7DBC-448B-A2F4-A8805EFAC393.jpeg25C2DD1E-7776-491E-BBCE-5F2D1EA935E3.jpeg
                   Reply  Wed May 12 16:52:08 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 3878D102-C5BB-46AE-B90B-540CFDE3100B.jpegSPSR785_NX_12-05-2021_173959.pdfSPSR785_SX_12-05-2021_183434.pdfSPSR785_NS_12-05-2021_191513.pdf
                      Reply  Thu May 13 16:31:40 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 6x
                         Reply  Thu May 13 19:09:16 2021, rana, DailyProgress, Laser, delay line frequency discriminator 
                         Reply  Fri May 14 18:43:25 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 994ECC7F-C5FE-4E7B-8F19-B1C118DCE6CE.png
                            Reply  Thu May 20 12:50:56 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 
                               Reply  Fri May 21 14:15:21 2021, aaron, DailyProgress, Laser, current noise of custom current drivers 5012D147-8B13-478C-BB83-57A71A2B304A.jpeg467DEC59-01B1-40CD-9F4E-4D9D87183A78.jpegABC2A51B-6726-4F9C-AD88-551ED7C90EEF.jpeg
                               Reply  Tue Aug 17 14:04:27 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 3A1E242C-F4F6-4A87-B2E8-E74839BE542C.jpeg
                                  Reply  Wed Aug 18 09:55:13 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 0A96102F-5465-456B-93BF-E2B9D4A7E96C.jpegtrim.2553D656-98A0-442D-9185-4C5252B2B727.MOVtrim.787F04FC-8DED-4501-B67D-FF98EC5D5D56.MOV
                                     Reply  Thu Aug 19 14:21:35 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 007FC2D7-F29B-4636-9CE7-04CBC3B789F7.jpeg1F1E68F0-199F-4E1C-B909-883A521E06CF.jpegScreenshot_from_2021-08-19_17-53-58.png
                                        Reply  Fri Aug 20 11:03:44 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 30A43669-5DFF-400A-BEB4-7EF71BBAE1A6.jpegA3BF5DA5-32E5-42A5-A1D8-9270C3D88518.pngScreenshot_from_2021-08-20_16-11-26.pngScreenshot_from_2021-08-20_16-20-48.png
                                           Reply  Mon Aug 23 13:38:57 2021, aaron, DailyProgress, Laser, delay line frequency discriminator Screenshot_from_2021-08-23_16-42-48.png
                                              Reply  Tue Aug 24 16:44:39 2021, aaron, DailyProgress, Laser, delay line frequency discriminator beats_regions.pdfTeraxion_noise.pdfEW_timeseries.pdf
                                                 Reply  Thu Aug 26 11:58:50 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 9x
                                                    Reply  Fri Aug 27 15:27:38 2021, rana, DailyProgress, Laser, delay line frequency discriminator 
                                                    Reply  Tue Aug 31 15:14:28 2021, aaron, DailyProgress, Laser, quieting the Rio W and Teraxion beat notes, but not much help beats_regions_base2.pdfbeats_regions_base2.pdfTeraxion_noise_base2.jpgDLFD_foam.pdf
                                                       Reply  Wed Sep 1 12:20:18 2021, rana, DailyProgress, Laser, quieting the Rio W and Teraxion beat notes, but not much help 
                                     Reply  Thu Aug 19 16:32:47 2021, rana, DailyProgress, Laser, delay line frequency discriminator 
       Reply  Tue May 4 10:50:22 2021, aaron, DailyProgress, Laser, marconi locking 6DC5CB12-BCDF-4550-AFB8-42D3DC354AED.jpegSPSR785_04-05-2021_152326.pdf
          Reply  Wed May 5 00:27:10 2021, rana, DailyProgress, Laser, marconi locking 
Message ID: 2801     Entry time: Tue Aug 24 16:44:39 2021     In reply to: 2798     Reply to this: 2802
Author: aaron 
Type: DailyProgress 
Category: Laser 
Subject: delay line frequency discriminator 

[aaron, rana]

  • Drive RF amplifier with -6 dBm from Marconi (amp is +16 dB), and observe RF level at the 1% RF couple out just before the delay line box
  • Sweep the Marconi carrier frequency from 75 to 230 MHz at 1 MHz / 50 ms. Observed a somewhat assymetrical sine wave, indicating there's some switching or other issue giving us amplitude-to-phase coupling at the mixer (see Rana technical docs above)
  • Removed the Marconi drive and power off RF amp, then open up the delay line box to add a 4 dB attenuator on the RF path.
  • The output of the delay line box is now a more or less symmetrical sine wave across our sweep
    • Turned off the sweep, and tuned the carrier frequency to record a 382 mV pkpk output of the discriminator between about 75 MHz (higher voltage) and 145 MHz (lower voltage). THe null is around 108 MHz
  • Disconnected the Marconi from the system, and instead plugged in the Rio laser E x Rio laser W beat note from the 1611. Tuned the laser current to null the discriminator output, and recorded the beat frequency with the Moku phasemeter. The lasers have been on for a while and are no longer drifting, so apparently it's staying within the phasemeter bandwidth.
    • After measuring Rio E x Rio W, swapped in the Teraxion laser and measured Rio E x Teraxion. The Teraxion laser exhibited some low frequency drift (several MHz / min), which seemed to improve over time
    • Then, measured Rio W x Teraxion
    • Lastly, I sent a sine wave from the Marconi (amplitude chosen such that the signal going into the moku remained -35 dBm) into the phasemeter to measure its noise floor.

Data logged:

File name measurement notes
EW_note_20210824_164439.li Rio E x Rio W laser, near 112 MHz, with Moku phasemeter. 488 Hz sampling  
EW_note_20210824_170434.li Rio E x Rio W laser, near 112 MHz, with Moku phasemeter. 15.6 kHz sampling  
EX_note_20210824_175820.li Rio E x Teraxion laser monotonic, low frequency drift, several MHz / min
WX_note_20210824_184820.li Rio W x Teraxion laser  
Marconi_20210824_194102.li Pure sine at 110 MHz  

We uploaded the data from moku to dropbox, and pulled it to spirou via the web interface. Should give the workstations dropbox.

Later, I realized we could probably have done better by sending the output of the 1611 directly to the moku. Instead, we were amplifying +16 dB then using an RF coupler to pick off 1% for the moku.

Figures:

  1. ASD for the three beat notes, using 10 minutes at 488 Hz sampling for each. Each curve is the ASD from Welch's method with bias-adjusted median averaging, 50% overlap and a Hanning window. The shaded regions are the 15.8-84.1% percentiles. Welch's method is applied 'decade-by-decade', so within each frequency decade the window size is adjusted to maximize the number of averages (as in labutils/moku/modifiedPSD.py). The ASD of the Marconi sine wave is also shown for a rough noise floor reference.
  2. The ASD for the Teraxion laser using a three corner hat with the PSD from attachment 1.
  3. The remaining figures are the time series plots, for reference.
Attachment 1: beats_regions.pdf  41 kB  Uploaded Wed Aug 25 16:08:38 2021  | Hide | Hide all
beats_regions.pdf
Attachment 2: Teraxion_noise.pdf  19 kB  Uploaded Wed Aug 25 16:08:44 2021  | Hide | Hide all
Teraxion_noise.pdf
Attachment 3: EW_timeseries.pdf  219 kB  Uploaded Wed Aug 25 16:12:50 2021  | Hide | Hide all
EW_timeseries.pdf
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