OEwaves lock and Finesse measurement, posted by Ronic Chiche at Optical room about lasers and optics
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this morning, I locked the FP cavity with the OEwaves CW laser and the "Fred fiber amplifier" used at 500mA of pump current.
the lock was much more easy than with the Koheras.
I had to change the 10GHz EOM which seems damaged as the modulation depth is very low and does not allow a Finesse measurement by modulation |
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 |
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 |
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New mirrors batch informations, posted by Ronic Chiche at ThomX igloo about lasers and optics
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the 2 files describe the specfications for the 16 mirrors ordered (4 for ThomX + spare, 4 for SBOX + spare) and the measurements made by the LMA.
I add also a 3rd file in which all the "special' mirrors are referenced. |
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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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Mounts installation and cavity alignment, posted by Xinyi Lu at Optical room about lasers and optics
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Over the last two days, Viktor, Ronic and I have started to install the mirror mounts and try to align the cavity.
- We used the Menhir laser @ 160MHz for alignment.
- To make it easier to operate, we removed some lenses and waveplates, and kept only a few necessary reflective mirrors. |
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Mounts installation and cavity alignment, posted by Xinyi Lu at Optical room about lasers and optics
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Over the past few days, Viktor, Ronic and I have continued to align the cavity. We installed 4 mirrors and monitored the transmitted laser with
a CCD and photodiode. By adjusting the motors of the cavity mirror stages and the injector mirrors, we obtained resonances and less symmetric TEM20-like
patterns. Possible reasons for this are a mismatch between the beam sizes of the laser and the cavity mode, and the mounts are installed in rough |
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Mounts installation and cavity alignment, posted by Xinyi Lu at Optical room about lasers and optics
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- Over the last few days, Viktor, Ronic and I have reinstalled the mounts and realigned the cavity with CW laser and old mirrors. By optimizing the injector
mirrors, we got the fundamental mode at the transmission. We measured the beam size in the M2 window with a diameter of 2.5 mm.
- The current coupling efficiency is low. There is a need to increase the coupling in order to lock the cavity and measure FSR and finesse. |
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Motors for D-shaped mirrors, posted by Loïc Amoudry at Optical room about mechanics | lasers and optics
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Motors have been installed on 16/10/18. No problem with them.
Effect of the motors tested on 17/10/18. No improvement. But they give the possibility to perfectly cut HOM or let them go through as show
the following picture of a 2.2 mode at ~340 mW in trans and 70% coupling @4A. |
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Mirrors features, come back from LMA, posted by Loïc Amoudry at Optical room about lasers and optics
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Mirrors arrived today from LMA. Their features are damaged.
Photos avant ou après nettoyage, pas clair dans le mail de Laurent :
"J'ai commencé à nettoyer M1 et M2 avec notr methode habituelle et je me suis aperçu que sur la partie centrale |
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Mirrors cleaning, posted by Loïc Amoudry at Optical room about lasers and optics
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The new mirrors didn't give expected results. Then the 4 old mirrors have been sent to LMA on 12/11/18 for a cleaning and caracterization before
and after cleaning. Also asked for a diffusion/absorption map on the mirrors if possible. They didn't really answered on what will they do.
Received on 13/11/18 by LMA. |
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Mirror's installed, posted by Loïc Amoudry at Optical room about lasers and optics
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| The initial 400kW SBOX mirrors which have been cleaned ont 28th of november have been installed this morning on the SBOX. |
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Mirror's cleaning and microscope imaging, posted by Loïc Amoudry at Optical room about lasers and optics 14x
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On 10th of december 2020 we cleaned the SBOX mirrors and took microscope images (the name of the images indicates what they are).
There are 7 mirror, the initial M1 (spot in the center), M2 (spot on the edge), M3 and M4 which made the 200-400kW and the M2, M3 and M4 SPARE.
The difference we make between M3 and M4 SPARE is the number on the box (11 or 13). |