Amplifier output power , posted by Loïc Amoudry at Optical room about lasers and optics
|
We checked the Dichroic mirror we have : it is a DMSP1000 shortpass dichroic mirror as specified in this post.
The Arrow engraved on the edge of the mirror points on the AR surface !
not on the HR surface... |
|
33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
|
This morning, with Aurélien and Daniele, we did the swap between the 33MHz and 133MHz oscillators.
now, the 33MHz oscillator is on ThomX inside the casemate.
it has been restarted and some laser is going out. |
33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics 
|
Yesterday with Aurélien, we try to make the laser modelock using the Smaract translation stages embedded inside the laser head.
unfortunately, we got some errors when we try to do the "calibration" and "reference" of both Smaract stages !
we contacted by email M. Nicoul to help us on this topic |
|
33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
|
Today, we used an "ELI-NP" Smaract controller made with these 2 references :
MCS-3CC-ETH-TAB (SN 2271) => main controller
MCS-3S-EP-SDS15-TAB (SN 2472) => sensor module |
|
33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
|
Yesterday, we put back the 33MHz oscillator into the casemate with the new Smaract controller.
after switching ON the laser controller, we saw some power at the output but we have to check if the laser is modelock or not.
Ronic |
|
33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
|
Today, we succeded to make the laser modelock.
the ouptut power is above 35mW (the powermeter was saturated)
here is a screenshot of the signal on the scope. |
New Mirrors from LMA _ Images, posted by Manar Amer at Optical room about lasers and optics
|
Today we tested a mirror from one patch
image is for the front face of the mirror
PowerPoint has more details about the images |
|
33MHz laser SN2439 back to Orsay, posted by Ronic Chiche at Optical room about lasers and optics
|
As the general local network for the FP-cavity devices is 192.168.xxx.xxx, I changed the IP adress of the smaract laser motors (Frep and CEP) controller.
For that, I used the embedded web server as described in the manual in attached file.
the new adresses are : |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
pour préparer le lock cavité-anneau, j'ai un setup de lock en salle optique entre le laser OneFive 133MHz et un synthé à
533MHz (133MHz x4).
ce matin, j'ai pu locker les 2 ensembles avec le laselock avec une stabilité RMS, je pense inférieure à la ps. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
régler le problème 1:
Kevin m'a apporté un déphaseur Minicircuits JSPHS-661 (400-660MHz / 180° de phase) qui permet de déphaser le 500MHz
de ~ 1ns avec une tension DC 0-10V. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
Today, I installed a DB9-DB9 female-male cable on the PZT connector of the FP-cavity.
the PZT is connected between pins 1 and 2, with a capacitance around 70nF.
I need to make a prolongator cable BNC-DB9 female to connect it to the feedback system. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
Today, I connected the BNC-DB9 female prolongator cable to the FP-cavity PZT cable (DB9-DB9) and to the channel B of the Laselock.
I additionnaly connected the reflected laser beam (normally connected to scope ch2) to the spectrum analyzer @ 1GHz to observe the 30th harmonic
of the laser comb. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
this afternoon, I installed the frequency detection scheme in the bunker :
- I changed the large reflected photodiode DET100 by a fast small DET10.
- a 50ohms splitter is connected to the photodiode : |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
this afternoon, I tried to lock the FP-cavity on a local 500MHz synthesizer as a frequency reference
(it's faster to change the frequency from the sythesizer than from the FP cavity !!!)
I found some parameters on the PID of the Laselock to phase-lock the reference and the FP-cavity |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
this morning, I added a Thorlabs lowpass filter at 1kHz after the mixer and a resistor at the Laselock output to the FP-cavity PZT.
I set the PID with P=10 and I=D~0
in attachement, a plot of the 500MHz mixer output, before and during the lock. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
this afternoon, I firstly connected the HV output of the Laselock to the FP-cavity PZT : https://elog.lal.in2p3.fr/FPC/THOMX+commissioning/248
locking the FP-cavity on the local synthesizer works better with the improved HV output range.
the ~20Hz oscillation in the beating signal of the FP-cavity/synthesizer is still there. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
this afternoon, we were able to lock the laser on the FP-cavity and the FP-cavity on the Ring reference oscillator in a same time from the control room.
the procedure when laser, cavity and reference oscillators are far in frequency, is :
1) start the amplifier to get the laser signal in the reference photodiode used to measure the 33MHz. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
after a sudden FP-cavity Finesse increase, we had to install the Fast Feedback Loop in order to continue to lock the cavity.
this afternoon, I was able to lock both the FP-cavity and the Laser on the 500.25MHz oscillator reference.
I had to change the CEP to reduce the effective Finesse and help to get a better stabililty => P ~ 25kW inside the FP-cavity for 30% of laser |
|
Laser FP operation, posted by Daniele Nutarelli at Optical room about lasers and optics
|
This morning FP Laser was operating well locked at 30 KWatts in stable vay.
There are some fluctuations due tu pointing instabilities probably dues to temperature fluctuations in de bunker.
In the attacced picture are reported the lock parameters and signals. |
|
lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
|
This morning with Daniele, we changed the laser/RF locking scheme :
1) we use the laser 33MHz internal photodiode to do some beating with the 33MHz RF generator (A Rigol generator locked on the 500MHz Ring oscillator).
this beating is only for monitoring purpose, in order to manually adjust the laser frequency at the beginning of a run. |