CELIA 100W laser amplifier repair , posted by Ronic Chiche at Optical room about lasers and optics
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this morning with Alice, we sent the Menhir 160MHz injected in a fiber (with 6mW at the end of a long fiber) into the laser amplifier, to look for leakage
or damage in the first stages of the amplifier (the amplifier is totally off).
first of all, we checked for light scattering around the laser crate with a sensitive optical card => nothing |
CELIA 100W laser amplifier repair , posted by Ronic Chiche at Optical room about lasers and optics 
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this afternoon, we saw some electric cables badly connected to their power supply.
we fixed it by soldering them together and screwing the result to the power supply.
(see 1st image) |
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optical table cleaning, posted by Ronic Chiche at Optical room about utilities
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this morning with Alice and Daniele, we removed all the optics elements and equipments from the SBOX optical table and started to clean it.
the dust meter count 0 on all particle sizes after the cleaning.
we observed a small part of the SBOX which seems to be oxydised (see picture). |
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optical table cleaning, posted by Ronic Chiche at Optical room about utilities
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this afternoon, we checked the dust meter which is at 0 for 1 and 5µm dust particles but ~ 2000-3000 for 0.3µm particles.
we opened the two top panels to let the air flow clean the inside of the vessel.
we observed some other minor oxydised regions (than the one taken in picture) on the external parts of the inox panels but at first sight, nothing |
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CELIA 100W laser amplifier repair , posted by Ronic Chiche at Optical room about lasers and optics
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friday morning, we add a zoom call with Jerome Lhermite about the amplifier repair.
he approximately confirmed the amplifier scheme from the Loic thesis.
he suggested to: |
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optical table cleaning, posted by Ronic Chiche at Optical room about utilities
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now, it seems the table is clean enough (dust meter counts 0 particles) to install a 2 mirrors FP-cavity.
Ronic
Chiche wrote:
this afternoon, we checked the dust meter which is at 0 for 1 and |
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Alignment of a 2-mirror FP cavity, posted by Ronic Chiche at Optical room about mechanics | lasers and optics
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today with Alice,
- we measured the height of the SBOX windows center : 140mm from the optical table.
- we set the laser fiber colimator exactly at this height. |
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first attempt to lock, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | detectors and electronics
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With Alice, we installed the EOWaves oscillator to be locked on the FP-cavity (T1 ~ 2500ppm, T2 ~ 10ppm => F ~ 2500)
FSR = 216MHz => LW = 86kHz.
We installed the PDH box, and we got some error signal, but the shape of the transmission signal and error signal is a bit strange... |
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Installation of the avalanche photodiode, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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After installing the 2nd EOM, we had some trouble to be able to lock again.
One possible reason was the very low signal level in transmission, which is important to trigger the locking system (and stop it).
See the Alice post for details, but we were able to measure only once the Finesse of the cavity at around 2600. |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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we have all the adaptor plugs for connecting the chiller.
so, I tested first the chiller connected in closed loop (on itself).
there is no manual, so procedure is not completely clear... |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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now, I connected the chiller circuit to the amplifier, thanks to the adapters.
chiller IN => blue pipe => laser OUT
chiller OUT => black pipe => laser IN |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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pipes are maybe too long ?
we can use the Darcy-Weisbach + Blasius laws (non linear laws).
I asked to ChatGPT, Claude, Mistral and MathGPT to solve it with these parameters : |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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I drained the chiller to install again the short pipe (< 1m) in closed loop.
then, I filled again the chiller and did the compression process to obtain 1bar.
in that case, the flow measured by the chiller is correct about 5.8Lpm. |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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now, I installed the long pipes (2x 3m) in closed loop (without the amplifier connected), but the exact ones used to connect the laser, with the same
pipe adapters.
after the compression process, the chiller works at 0.9 bar and the measured flow is 4.7Lpm. |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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I cut a small part of the black pipe on the amplifier side (could it be slightly deformed by a try with an other type of adapter ?), with the dedicated
tool, changed the adapter and plugged it more firmly in the pipe (pipe deeply inserted in the adapter).
it seems, there is no more leakage. |
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Neolase amplifier installation, posted by Ronic Chiche at Optical room about mechanics | lasers and optics | cabling
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as soon as I connect the amplifier to the pipes, the flow decreases to 1.7Lpm.
and the filling process is very long and noisy, as there was something blocking the filling process... |
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Transmission Measurements for the Mirrors. , posted by Manar Amer at Optical room about lasers and optics 6x
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Thursday 10 December 2020: First Test Measurement - Inside Box
The transmission ( T ) for the mirrors of SBOX
and ThomX was measured over a range from the center of the mirror up to 5mm.
The first setup was initially done while the
mirrorr is installed inside the metal box, when measuring T we observe that there is an erregular change in the power measured as we move azay from |
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OEwaves CW Laser - Phase Noise , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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We started measuring the phase noise on the OEwaves CW laser.
Class 3b
wavelength 1.5 um
The
procedure is done using self coupling of the laser
splitter 50%-50%\
delay line 100 m
all fibers are PM type
(polarity maintained)
Photodetector is "lab buddy", very fast diode.
Note: différance from schematic (we did not |
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OEwaves CW Laser - Phase Noise , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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a correction on the wavelength of the laser it is 1030 um
Manar
Amer wrote:
We started measuring the phase noise on the OEwaves CW laser.
Class |
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OEwaves CW Laser - Phase Noise , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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correction on unit 1030 nm
Manar
Amer wrote:
a correction on the wavelength of the laser it is 1030 um |