new position of smaract motors, posted by Aurélien Martens at Optical room about detectors and electronics | software
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the M1 is not at 5.1045mm to put the fundamental on the scanning range of the laser piezo
M2 still at 5.104mm
M3/M4 at -2.9mm still |
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new position of smaract motors, posted by Aurélien Martens at Optical room about detectors and electronics | software
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after 3hours (1pm --> 4pm) the cavity moved by 12um in total
new positions: +5.1065mm on M1 and M2 (5.1050 before)
the drift is 4um/hour which amounts to about 10kHz drift / hour+the temperature of the optics room also changed unfortunaltey (linked to extinction |
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Locking with fast analog loop on AOM, posted by Ronic Chiche at Optical room about lasers and optics
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in addition to the standard locking scheme with the GHz laser PZT,
we added an AOM after the PDH modulation EOM and we drove it with an FM modulated signal generator (FMDev = 2.4MHz) seeded by the error signal.
(we didn't put a 50ohm plug to adapt the error signal coming from the PDH box, otherwise, it is too much smaller) |
Finess and coupling measurement, posted by Blanc at Optical room about lasers and optics | detectors and electronics 
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We did the measurement of the Finess and coupling with the NKT, with 2 EOM, without AOM (so the lock signal is noisy), on the burst line.
For the coupling, we have the same value as with the GHz locked on the burst line too, which is around 20 percent.
it seems this low coupling comes from the geometrical coupling as we observed an incoming beam bigger than the cavity mode on the cameras. |
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Setup and measurements, posted by Blanc at Optical room about lasers and optics | detectors and electronics
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To summerize the results of this week :
We made the setup in attachement 5 and align it to have the good mode in the cavity (TEM00).
With the good alignment, we found the lock of the GHz, in attachement 1. We used the motors in the cavity to position very precisely the mirrors |
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PZT resonant frequencies, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics
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we have excited the PZT with a swept sinus wave from 1kHz to 10kHz and from 10kHz to 100kHz.
here are the 2 different spectrums:
- the 1kHz-10kHz is a standard spectrum where we see the impedance behavior of the PZT: Zpzt ~ 1/jCw |
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Amplitude GHz oscillator phase noise with PZT effect, posted by Ronic Chiche at Optical room about lasers and optics
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3 phase noise measurements made on the Amplitude GHz oscillator with different PZT configurations :
- black curve: PZT connector is open
- green curve: PZT connector is shorted by 50 ohms |
Phase noise measurement of the Amplitude MIKAN, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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MIKAN phase noise and RIN measurements:
Ronic
Chiche wrote:
Coupling into a 50-50% fiber coupler using the Thorlabs XYZ table |
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Amplitude GHz oscillator phase noise with PZT effect, posted by Ronic Chiche at Optical room about lasers and optics
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Thorlabs PZT datasheet.
Reference: PC4QR
Ronic |
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1GHz oscillator Frep measurement, posted by Blanc at Optical room about mechanics | lasers and optics | detectors and electronics
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The optical spectrum of the GHz oscillator: FWHM ~ 4nm
Blanc
wrote:
a previous cavity FSR measurement was giving a center frequency around 867.5MHz. |
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Presentations, posted by Blanc at Other about utilities
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| Here the first part of all the presentations since the beginning of the project. |
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Presentations, posted by Blanc at Other about utilities
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| Here the second part of all the presentations since the beginning of the project. |
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Presentations, posted by Blanc at Other about utilities
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| Here the last part of all the presentations since the beginning of the project. |
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new smaract positions, posted by Aurélien Martens at Optical room about mechanics | software
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| M1 and M2 at 5.1085mm and M3 and M4 at -2.9mm |
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input and output power of the AOM 50MHz, posted by Blanc at Optical room about lasers and optics | detectors and electronics
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Input power of the AOM :
150mW
output power of the AOM : |
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Différence de fréquence Tangor/Lockline, posted by Blanc at Optical room about lasers and optics | detectors and electronics
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- On a observé que le fondamental du Tangor et celui de la Lockline n'étaient pas situés à la même fréquence.
Avec la différence de tension donnée par le piezo entre les deux et le déplacement du piezo en fonction de la tension appliquée
donnée par sa datasheet (150 V pour 20 µm), on obtient un écart de fréquence de 121 MHz [Image 1]. |
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Données pour la baisse en cadence, posted by Blanc at Optical room about lasers and optics 7x
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Position Cam :
692;363 NF_inj
520;193 FF_inj |
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Tests et mesures lockline, posted by Blanc at Optical room about lasers and optics
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Mesures de puissance fibres lockline :
AVANT POLISSAGE
injection premier étage : 15 mW |
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Tests et mesures lockline, posted by Blanc at Optical room about lasers and optics
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Blanc
wrote:
Mesures de puissance fibres lockline : |
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Suite Mesures de puissance lockline, posted by Blanc at Optical room about lasers and optics
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Changement d'AOM pour passer sur l'AOM 200 MHz.
Le schéma suivant récapitule les mesures prises.
Il y a eu une chute de la puissance en sortie de la fibre bleue de la lockline. |