 Thu Apr 18 20:47:54 2019, Joe, Optics, , OMC initial alignment and locking 
|
[Joe, Phillip, Koji, Stephen]
*draft post, please add anymore info if I missed something*
made initial alignment of the cavity. To do this we used the periscope mirrors to aim the incoming beam at the centre of the |
|
Fri Apr 19 09:21:07 2019, Philip, Optics, , Cleaning of OMC optics
|
ach[Joe, Phillip, Koji, Stephen]
Work from 17.04.2019
First contact cleaning of OMC optics |
|
Fri Apr 19 09:35:28 2019, Joe, General, , Adjusting cavity axis, re-alignment of OMC and locking
|
[koji,philip, joe, liyuan, steven]
*still need to add photos to post*
PZT 11 was removed and inspected for so dust/dirt on the bottom of the prism. We saw a spot. We tried to remove this with acetone, |
 Fri Apr 19 11:34:19 2019, Koji, Optics, , OMC initial alignment and locking
|
The spot on CM1 was found displaced by 3.4mm (horiz.) and 3.0mm (vert.) in the upper right direction looking from the face side.
The spot on CM2 was found displaced by 1.2mm (horiz.) and 1.8mm (vert.) in the upper left direction looking from the face side.
The drawing on the left side of the attachment shows the estimated misalignment when we think they all come from the curved |
|
Mon Apr 22 09:54:21 2019, Joe, General, , Shortening cavity (A5,A14,PZT11,PZT22) to get closer to design FSR
|
[Koji,Joe,Philip,stephen]
in units 20um per div on the micrometer [n.b. we reailised that its 10um per div on the micrometer]
CM1 inner screw pos: 11.5 |
|
Mon Apr 22 19:54:28 2019, Koji, General, , OMC(004): Spot positions at the end of Apr 22nd
|
| |
|
Mon Apr 24 15:29:48 2023, Camille Makarem, Optics, , summary of zygo setups 6x
|
Summary of Zygo setups
Initial Zygo Setup:
Our initial Zygo setup consisted of a flat transmission sphere with the 0.5" curved mirror mounted against a 1" flat mirror. |
|
Wed Jul 15 22:23:17 2015, Koji, Electronics, AM Stabilized EOM Driver, E1400445 first look
|
This is not an OMC related and even not happening in the OMC lab (happening at the 40m), but I needed somewhere to elog...
E1400445 first look
LIGO
DCC E1400445 |
|
Sat Jul 18 11:37:21 2015, Koji, Electronics, AM Stabilized EOM Driver, D0900848 power board ~ oscillation issue solved 6x
|
Power Supply Board D0900848 was oscillating. Here is the procedure how the issue was fixed.
PCB schematic: LIGO DCC D0900848
0. Extracting the power board. |
|
Wed Jul 22 09:43:01 2015, Koji, Electronics, AM Stabilized EOM Driver, Power supply test of the EOM/AOM Driver
|
Serial Number of the unit: S1500117
Tester: Koji Arai
Test Date: Jul 22, 2015 |
|
Wed Jul 22 10:15:14 2015, Koji, Electronics, AM Stabilized EOM Driver, RF test of the EOM/AOM Driver S1500117
|
7) Make sure the on/off RF button works,
=> OK
8) Make sure the power output doesn't oscillate, |
|
Sat Jul 25 17:24:11 2015, Koji, Electronics, AM Stabilized EOM Driver, RF test of the EOM/AOM Driver S1500117 7x
|
(Calibration for Attachment 5 corrected Aug 27, 2015)
Now the test procedure fo the unit is written in the document https://dcc.ligo.org/LIGO-T1500404
And the test result of the first unit (S1500117) has also been uploaded to DCC https://dcc.ligo.org/LIGO-S1500117 |
|
Tue Jul 28 18:36:50 2015, Koji, Electronics, AM Stabilized EOM Driver, RF test of the EOM/AOM Driver S1500117
|
Final Test Result of S1500117: https://dcc.ligo.org/LIGO-S1500117
After some staring the schematic and checking some TFs, I found that the DAQ channels for MON2 have a mistake in the circuit.
Differential driver U14 and U15 of D0900848 are intended to have the gain of +10 and -10 for the pos and neg outputs. |
|
Mon Aug 10 02:11:47 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151
|
This is an entry for the work on Aug 3rd.
LIGO DCC E1500151
Power supply check |
|
Mon Aug 10 11:39:40 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151
|
Entry for Aug 6th, 2015
I faced with difficulties to operate the RF AM detectors.
I tried to operate the RF AM detector. In short I could not as I could not remove the saturation of the MON outputs, no matter how jiggle the |
|
Mon Aug 10 11:57:17 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151
|
Spending some days to figure out how to program CPLD (Xilinx CoolRunner II XC2C384).
I learned that the JTAG cable which Daniel sent to me (Altium JTAG USB adapter) was not compatible with Xilinx ISE's iMPACT.
I need to use Altium to program the CPLD. However I'm stuck there. Altium recognizes the JTAG cable but does not see CPLD. (Attachment 1) |
|
Mon Aug 10 12:09:49 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151
|
Still suffering from a power supply issue!
I have been tracking the issues I'm having with the RF AM detector board.
I found that the -5V test point did not show -5V but ~+5V! It seemed that this pin was not connected to |
|
Fri Aug 28 01:08:14 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151 ~ Calibration
|
Worked on the calibration of the RF AM Measurement Unit.
The calibration concept is as follows:
Generate AM modulated RF output
Measure sideband amplitude using a network anayzer (HP4395A). This gives us the SSB |
|
Fri Aug 28 02:14:53 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151 ~ 37MHz OCXO AM measurement
|
In order to check the noise level of the RFAM detector, the power and cross spectra for the same signal source
were simultaneously measured with the two RFAM detectors.
As a signal source, 37MHz OCXO using a wenzel oscillator was used. The output from the signal source |
|
Tue Sep 8 10:55:31 2015, Koji, Electronics, AM Stabilized EOM Driver, RF AM Measurement Unit E1500151 ~ 37MHz OCXO AM measurement
|
Test sheet: https://dcc.ligo.org/LIGO-E1400445
Test Result (S1500114): https://dcc.ligo.org/S1500114 |
|
Fri Jun 29 11:26:04 2012, Zach, Optics, Characterization, RoC measurement setup
|
Here is the proposed RoC measurement setup. Koji tells me that this is referred to as "Anderson's method".
We would like to use a linear cavity to measure the RoC of the curved mirrors independently (before forming the ring cavity), since the degeneracy
of HOMs will make the fitting easier. |
|
Wed Jul 18 23:20:13 2012, Koji, Optics, Characterization, Mode scan results of ELIGO
|
Nic Smith sent me a bunch of elog lists where the results of the mode scan can be found.
From Nic:
There have been many mode scan analyses done at LLO: |
|
Sun Jul 22 15:56:53 2012, Zach, Optics, Characterization, RoC measurement setup
|
Here is a more detailed version of the setup, so that we can gather the parts we will need.
|
|
Thu Oct 18 20:23:33 2012, Koji, Optics, Characterization, Improved measurement
|
Significant improvement has been achieved in the RoC measurement.
The trans PD has much more power as the BS at the cavity trans was replaced by a 50% BS. This covers the disadvantage of using the a
Si PD.
The BB EOM has a 50Ohm terminator to ensure the 50Ohm termination at Low freq.
The length of the cavity was changed |
|
Wed Nov 7 01:28:20 2012, Koji, Optics, Characterization, Wedge angle test (A1)
|
Wedge angle test
Result: Wedge angle of Prism A1: 0.497 deg +/- 0.004 deg
|
|
Thu Nov 8 13:24:53 2012, Koji, Optics, Characterization, More wedge measurement
|
A1
Horiz Wedge 0.497 +/- 0.004 deg
Vert Wedge 0.024 +/- 0.004 deg |
|
Fri Nov 9 00:43:32 2012, Koji, Optics, Characterization, Further more wedge measurement
|
Now it's enough for the first OMC (or even second one too).
Today's measurements all distributed in theta>0.5deg. Is this some systematic effect???
I should check some of the compeled mirrors again to see the reproducibility... |
|
Sat Nov 17 02:31:34 2012, Koji, Optics, Characterization, Mirror T test
|
Mirror T test
The mirror was misaligned to have ~2deg incident (mistakenly...) angle.
|
|
Mon Nov 19 13:33:14 2012, Koji, Optics, Characterization, Resuming testing mirror RoCs
|
In order to resume testing the curvatures of the mirrors, the same mirror as the previous one was tested.
The result looks consistent with the previous measurement.
It seems that there has been some locking offset. Actually, the split peaks in the TF@83MHz indicates |
|
Mon Nov 26 01:40:00 2012, Koji, Optics, Characterization, More RoC measurement
|
C1: RoC: 2.57845 +/− 4.2e−05m
C2: RoC: 2.54363 +/− 4.9e−05m
C3: RoC: 2.57130 +/− 6.3e−05m |
|
Tue Dec 18 20:04:40 2012, Koji, Optics, Characterization, Prism Thickness Measurement
|
The thicknesses of the prism mirrors (A1-A5) were measured with micrometer thickness gauge.
Since the thickness of the thinner side (side1) depends on the depth used for the measurement,
it is not accurate. Unit in mm. |
|
Mon Dec 31 03:11:45 2012, Koji, Optics, Characterization, Further more RoC measurement
|
Total (excluding C2, C7, C8): 2.575 +/- 0.005 [m]
New results
C6: RoC: 2.57321 +/− 4.2e-05m |
|
Wed Jan 2 07:35:55 2013, Koji, Optics, Characterization, Thickness of a curved mirror
|
Measured the thickness of a curved mirror:
Took three points separated by 120 degree.
S/N: C2, (0.2478, 0.2477, 0.2477) in inch => (6.294, 6.292, 6.292) in mm |
|
Wed Jan 2 07:45:39 2013, Koji, Optics, Characterization, First Contact test
|
Conclusion: Good. First contact did not damage the coating surface, and reduced the loss
- Construct a cavity with A1 and C2
- Measure the transmission and FWHM (of TEM10 mode) |
|
Thu Jan 10 18:37:50 2013, Koji, Optics, Characterization, Wedging of the PZTs
|
Yesterday I measured the thickness of the PZTs in order to get an idea how much the PZTs are wedged.
For each PZT, the thickness at six points along the ring was measured with a micrometer gauge.
The orientation of the PZT was recognized by the wire direction and a black marking to indicate the polarity. |
|
Wed Jan 16 14:10:50 2013, Koji, Optics, Characterization, Autocollimator tests of optics perpendicularity/parallelism
|
The items:
- Autocollimator (AC) borrowed from Mike Smith (Nippon Kogaku model 305, phi=2.76", 67.8mm)
- Retroreflector (corner cube) |
|
Sat Jan 19 20:47:41 2013, Koji, Optics, Characterization, Wedge measurement with the autocollimator
|
The wedge angle of the prism "A1" was measured with the autocollimator (AC).
The range of the AC is 40 arcmin. This means that the mirror tilt of 40arcmin can be measured with this AC.
This is just barely enough to detect the front side reflection and the back side reflection. |
|
Mon Feb 4 00:39:08 2013, Koji, Optics, Characterization, Wedge measurement with the autocollimator and the rotation stage
|
Method:
Mount the tombstone prism on the prism mount. The mount is fixed on the rotation stage.
Locate the prism in front of the
autocollimator.
Find the retroreflected reticle in the view. Adjust the focus if necessary.
Confirm that the rotation of the |
|
Wed Feb 6 02:34:10 2013, Koji, Optics, Characterization, Wedge measurement with the autocollimator and the rotation stage
|
Measurement:
A6: α = 0.665 deg, β = +3.0 arcmin (1.5 div up)
A7: α = 0.635 deg, β =
0.0 arcmin (0.0 div up)
A8: α = 0.623 deg, β = - 0.4 arcmin (-0.2 div up)
A9: α = |
|
Thu Feb 7 23:01:45 2013, Koji, Optics, Characterization, UV epoxy gluing test
|
[Jeff, Yuta, Koji]
Gluing test with UV-cure epoxy Optocast 3553-LV-UTF-HM
- This glue was bought in the end of October (~3.5 months ago). |
|
Fri Mar 1 23:52:18 2013, Koji, Optics, Characterization, Wedge measurement with the autocollimator and the rotation stage
|
Measurement:
E1: α = 0.672 deg, β = +0.0 arcmin (0 div up)
E2: α = 0.631 deg, β = - 0.3 arcmin
(-0.15 div down)
E3: α = 0.642 deg, β = +0.0 arcmin (0 div up)
E4: α = 0.659 deg, β |
|
Tue Mar 5 19:37:00 2013, Zach, Optics, Characterization, eLIGO OMC visibility vs. power measurement details
|
EDIT (ZK): Koji points out that (1 - Ti) should really be the non-resonant reflectivity of the aligned cavity, which is much closer to 1. However,
it should *actually* be the non-resonant reflectivity of the entire OMC assembly, including the steering mirror (see bottom of post). The steering mirror
has T ~ 0.3%, so the true results are somewhere between my numbers and those with (1 - Ti) -> 1. In practice, though, these effects are swamped by the |
|
Wed Mar 6 23:24:58 2013, Zach, Optics, Characterization, eLIGO OMC visibility vs. power measurement details
|
I found that, in fact, I had lowered the modulation depth since when I measured it to be 0.45 rads --> Psb = 0.1.
Here is the sweep measurement:
|
|
Fri Mar 15 02:15:45 2013, Koji, Electronics, Characterization, Diode testing
|
Diode testing
o Purpose of the measurement
- Test Si QPDs (C30845EH) for ISC QPDs Qty 30 (i.e. 120 elements) |
|
Sun Mar 17 21:59:47 2013, Koji, Electronics, Characterization, Diode testing ~ DCPD
|
- For the dark noise measurement, the lid of the die-cast case should also contact to the box for better shielding. This made the 60Hz lines almost completely
removed, although unknown 1kHz harmonics remains.
- The precise impedance of the setup can not be obtained from the measurement box; the cable in between is too long. The diode impedance should |
|
Wed Mar 20 09:38:02 2013, Zach, Optics, Characterization, [LLO] OMC test bench modified
|
For various reasons, I had to switch NPROs (from the LightWave 126 to the Innolight Prometheus).
I installed the laser, realigned the polarization and modulation
optics, and then began launching the beam into the fiber, though I have not coupled any light yet. |
|
Sat Mar 23 16:36:15 2013, Koji, Electronics, Characterization, Diode QE measurement
|
Quantum efficiencies of the C30665GH diodes were measured.
- The diode was biased by the FEMTO preamplifier.
- Diode Pin 1 Signal, Pin 2 +5V, Pin 3 open |
|
Wed Apr 3 17:39:38 2013, Koji, Mechanics, Characterization, Calibration of the test PZTs before the glue test
|
We want to make sure the responses of the PZT actuator does not change after the EP30-2 gluing.
A shadow sensor set up was quickly set-up at the fiber output. It turned out the ring PZTs are something really not-so-straightforward.
If the PZT was free or just was loosely attached on a plane by double-sided tape, the actuation response was quite low (30% of the spec). |
|
Thu Apr 4 01:35:04 2013, Koji, Optics, Characterization, Mode matching to the OMC cavity
|
The fiber output was matched with the lenses on a small bread board.
The detailed configuration is found in the following elog link.
http://nodus.ligo.caltech.edu:8080/OMC_Lab/105 |
|
Thu Apr 4 01:43:06 2013, Koji, Optics, Characterization, Mirror T measurement
|
[Zach, Koji]
The measurement setup for the transmission measurement has been made at the output of the fiber.
- First, we looked at the fiber output with a PBS. It wasn't P-pol so we rotated the ourput coupler. |