We have two EVAL-ADH4702-1CPZ evaluation boards which are nominally configured as 21V/V gain noninverting amplifiers.

First I provided power with a Newport +-15V supply, connecting +, -, and GND on the power supply to VCC, VEE, and GND respectively, on the eval board.

This resulted in a gain of 12.3dB up to about 100kHz

Next, I used the on board power supply by connecting the DC jack to the +15V and GND of the power supply. I then connected the power supply half of the eval board to the opamp circuit by jumping VCC_TRANSFORMER
to VCC, VEE_ TRANSFORMER to VEE, and GND_TRANSFORMER to AGND, as described in the manual of the eval board in the section "Initial Power-Up." These jumper wires are white, turquiose, and yellow.

I performed a transfer function and a pulse delay measurement.

I made some laser safety signs for the doors into B111A and B111B that have the power and required OD at different wavelengths. We still need to mount the metal laser safety signs, especially because the signs that light up are not particularly visible.

[JC, Daniel]
 

JC bought some first aid kits from amazon and I (temporarily?) placed them in the following locations:

B106 in the back

B110 by the fume hood on a shelf

B111A in the middle

B111B left of the shelves by the main entryway

B111D in the middle by the main entryway

B102 by the entryway

I cleaned the inside and outside of the plexiglass around the laser tables in B111A. It was still a little dirty, but it seems much cleaner than before.

[Jeff, Daniel]

We moved 12 cubbies from B102 to the B111 entryway to hold our clean and dirty shoes. I cleaned the inside of the cubbies with iso and water. I wasn't able to find a label maker, but 6 of the top cubbies should be for clean shoes and 6 of the bottom cubbies should be for dirty shoes.

With cubbies by the entryway, we won't get B111 dirty with shoes we're about to take off.

[Ian, Torrey, Jeff, Daniel]

Since we are limited by the 1 meter length of the fiber coming out of the amplifier, we decided to move the Laser and amplifier below the table from its current position on the shelves above the optical table. The thought is that that space will be very valuable and since we don't plan on touching the laser much we would rather put it under the table. Jeff found a rack that will fit under the table and we plan to put it under the South side of the table. This will give enough room to let the short fiber get to the top of the table. The amplifier will be mounted on the top of the short rack and the seed laser and polarizing paddles will be below it on a ThorLabs rack mount bread board. Daniel is mocking up how all the components will fit into the box. 

We also want to mock up a way to protect the fiber coming out of the amplifier. I want to put a plate in front of the rack mountable amplifier that attaches to the rack. This full face plate will protect any of the cables from getting kicked.

I have moved the cavity superoptics from B102 to B111B. They are located in the Lista cabinet nearest the optics tabled. See pictures. I have updated the wiki entry https://wiki.mccullerlab.com/bin/edit/DCC/S2400001?t=1729789909 accordingly.

Here is an example of a stabilizing controller we have used to lock the cavity, described in a few ways.

In the Moku UI it is described as:

Fast controller: PI controller: proportional gain +0.0 dB, integrator crossover 1.2 kHz, integrator saturation +43 dB, invert on

As a continous time transfer function, described in zpk (zeros, poles, gain) form, this is

z = [-1200*2*pi]

p = [-8.495*2*pi]

k = 1.0

Attached is a plot of the transfer function.

First, I connected to the Red Pitaya over local network by

1. Connecting the Red Pitaya (RP) via ethernet to the network (pLANk in b102). A usb connection via the COM port was not necessary.
2. finding the IP address on the board using "ip neigh" in terminal and matching the MAC address printed on the RP's ethernet port
3. navigating to the IP address using a browser
4. enter the password 'xilinx'

Next, I navigated to the notebook labelled "RunMe.ipynb" in the folder "Biquad SLA."

Overall, it's great! Worked first try.

The filters behave quite poorly when trying to put features at frequencies below 1MHz or so, as can be seen by the attempt to make a bandpass filter centered at 150kHz. This is perhaps no surprise given the sample rate of 125MHz and 16bit arithmetic.

I also measured the delay using an oscilloscope pulse as is described here, giving a result of 1.3 microseconds.

Thinking about incorporating this into the experiment makes me wonder: how can we pass new filter coefficients and open or close the loops without being in the Jupyter notebook? For example, could I send command strings to the IP address of the board?

I have re-attached all the fibers that were detached ahead of the move from B102 to B111. The last fiber management system was a mess so I have spent special care to make it much nicer this time around. I've fed all of the 775 and 1550 fibers that were in use (as well as the fourth AOM path in preperation for it being used) through a 1 inch flexible metal tube and fixed this tube to the table. I think it turned out quite well. Pictures attached.

While CNC machining a 1/4-20 breadboard pattern into a 2nd 10" CF flange, the tap broke going into the first hole in the middle of the part. It did two "peck taps" into this hole and then broke while tapping near the bottom of it, I think on the way down. I am not sure why it broke; maybe Paul Stovall (the head of the MCE shop) will know when he is in tomorrow.

There are a few paths forward: scrap the part or tap the rest of the holes. The best case senario is that we can remove the tap and fix the hole. If the hole isn't salvagable, I can drill it out and tap it with something like a 5/16-18 or 5/16-24 hole. We could also proceed with one hole that is useless.

There is a link to the instructions to sync the next cloud to ios or mac:

https://docs.nextcloud.com/server/19/user_manual/pim/index.html

The nextcloud is currently down so I cant test it to verify. I will add comments when it is back up

I ran the attached CNC code on the Haas VF-2 to add 37 tapped 1/4-20 holes with 1" spacing (a breadboard hole pattern) to a 10" CF Flange. I added a 0.0156" deep groove for venting so that we can cover a hole and not have a virtual leak.

The "pipeline" was to design the part in SolidWorks (CAD), give some CAM commands (tell it what holes to drill, how deep, etc), then "post" the G Code. I then copy the G Code into .txt file adn import it into the python script. This python script adds a custom cycle call (M97) to remove chips and allow me to visually confirm this. I then copy the code's output into a new .nc file. I then add the custom cycles at the bottom of the code. I can then read this G Code in the Haas.

I attached the flange the same as this post. Because the part and tool are flooded with coolant, the masking tape didn't do a great job at holding the flange to the knife edge and some chips got under the copper gasket. Luckily, these chips did not scratch the knife edge. I think the flange helped.

I used the 4 following tools: this #4 Cobalt Steel drill bit with a TiN coating, a 3/8" diameter 90° chamfer tool, this 1/4-20 steel bottom tap with 3 flutes and a black oxide coating, and a 1/8" diameter carbide end mill with 4 flutes and a TiAlN coating.

The tools did not appear to be too worn out after this cycle. There is a bit of wear on the tap and end mill, possibly due to earlier use.

After machining, I carefully removed the chips and used a stone and WD 40 to remove burrs from end mill.

I am going to machine another flange tomorrow and clean these Friday so that they can be baked out over the weekend.