restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software 
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we had to move the laser cavity motor to find the resonances and change a lot the CEP.
the CEP motor is at -524.1µm
we got ~75kW in the FP cavity without alignment but with CEP optimization. |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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after doing some alignment (walking procedure on the Y axis), and CEP optimization, I got 83kW for 33% on the laser amplifier with a coupling of ~60%
=> we have to check the input power after the amplifier.
I adjusted the FP and laser cavity motors to have a small 33MHz detuning with the RF reference (~10 Hz of beating @ 33MHz) |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this morning with Daniele, we are measuring the amplifier power just before the FP-cavity.
Casemate temperature @19.5°C
@0% : 205mW |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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After the summer power shutdown, I restarted all the equipements and got quickly ~80kW for 33% amplifier ratio with CEP optimization and without Alignment
optimization.
CEP motor position : -506µm |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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amplifier power measurement before the compressor CVBG.
we used a mirror in between the amplifier output and the compressor + a 2-mirror periscope to match the powermeter height.
amp ratio (%) power (W) |
fixing CVBG issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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the CVBG of the compressor module seems to have an issue.
here is the plan of the work :
1) faire des résonances avec la CFP |
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fixing CVBG issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics 12x
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1) this morning, I aligned to CFP to get back 82kW in the cavity for 33% of amplifier ratio.
thus, we can ajust the iris positions on the optical table to fix the CFP optical path before touching the CVBG.
2) we aligned the 5 iris. all of them were misaligned by 1-2mm, principaly vertically (maybe because we had to change the CFP frequency some |
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fixing CVBG issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning with Daniele, we realigned the amplifier beam axis on the iris position.
it was pretty fast an easy => we got rapidely some resonance and we locked back to 87kW @33% amp ratio after tuning CEP and alignment.
we tried to play on the L-shape but we didn't a clear effect. |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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after redoing the alignment of the CVBG, we got back the initial power in the FPC (87kW)
now, I checked the RF locking signals on the 2nd oscilloscope.
I get a strange ratio between the 33MHz beating and the 500MHz beating signals. |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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now, the Ring RF frequency is set to 500.067MHz.
so the CFP/laser frequency should be 500.067MHz/15 = 33.3378MHz.
the frequency was set to 33.378MHz !!! => it explains the frequency shift only on the 33MHz beating => I corrected the frequency on the |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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I changed a little bit the locking parameters (see picture) for the RF/FPC loop and it locked rapidely.
I asked Vincent to connect on the same scope the synchro signals to check if the FPC lock was OK => he connected 33MHz signals coming from
the laser and from the 33MHz RF generator. |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this morning, with Vincent :
- we added the 10Hz trigger to the CH2 on the remote scope (192.168.229.21) to check the synchronization at the right timing.
CH1 : 33MHz RING |
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Finding correct motors position and parameters to keep the lock during a move, posted by Ronic Chiche at ThomX igloo about mechanics
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this morning, I try to find a new region for MOT.03 and MOT.06 where we can move them without unlocking the cavity.
I started from the position:
MOT06 : ~ -785 000 |
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Finding correct motors position and parameters to keep the lock during a move, posted by Ronic Chiche at ThomX igloo about mechanics
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this morning with Daniele, we did a quite long run with this motor position and it seems we don't lose the lock too much.
the motor positions are:
MOT.03 (M4): -186 500 steps |
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Onefive 33MHz modelock loss, posted by Ronic Chiche at ThomX igloo about lasers and optics
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On Friday 11th of October, due to the Yvette flooding, all the AC power of ThomX have been shut down.
After the shutdown, I had to restart the Onefive oscillator but the laser modelock was lost.
I had to do a step of 1mm at 10mm/s with the Smaract motor on the rep rate channel (CH1) |
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Onefive 33MHz modelock loss, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning, I verified the reason why the seeder frequency was not displayed on the amplifier software screen:
one needs to start the amplifier (even at 0%) to see the seeder frequency !!!
now, we have 33.371MHz as expected ! => OK |
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Onefive 33MHz modelock loss, posted by Ronic Chiche at ThomX igloo about lasers and optics
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After the new Yvette flooding of the last week and the consecutive AC-shut down, I restarted this morning the laser with the same procedure (step of
1mm at 10mm/s with the Smaract motor on the rep rate channel (CH1)).
now, we have again 33.371MHz and 3.1mW input power as expected ! => OK |
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Onefive 33MHz modelock loss, posted by Ronic Chiche at ThomX igloo about lasers and optics
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For the modulation/demodulation generator for the PDH signal,
after a power shutdown, on can :
1) restart the generator to get the correct parameters: |
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Checking the amplifier power, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning, with Daniele, we checked the amplifier power, right after the CVBG (the power meter has to be placed on a metal plate above the large table
hole), and just at the input of the FP cavity, after the 1/4 and 1/2 waveplates (the power meter has to be placed on flat beam dump+ Thorlabs beam dump
+ V metallic mount to be at the right height). |
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Checking the amplifier power, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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we did a long term run (25 mn) with the powermeter located at the FPC position at 33% amplifier ratio.
the initial power was 18W .
then, it goes to 18.5W in 10 minutes, then 5 minutes later, it goes to 18.3W and stay stable until the end the run. |