CQNET-EntSource

Code for characterizing the entanglement source (Bob).

Overview

1. VapScanFunc.py (Python3, Commented, INQNET4) -- Contains functions for remotely controlling Bob's power supply.
2. runVapandPOpt1D_noScan.py (Python3, Commented, INQNET4) -- Does temperature scan of interferometer and runs the power optimization feedback code for the DC Bias pin of Bob's intensity modulator. Does not do an initial scan of DC Bias voltages for the power optimization.
3. runVapandPOpt1D.py (Python3, Commented, INQNET4) -- Does temperature scan of interferometer and runs the power optimization feedback code for the DC Bias pin of Bob's intensity modulator.
4. vdlControl.py (Python3, Commented, INQNET4) -- Controls the variable delay line and updates the delay from FQNET GUI's database.

• The "Other" folder contains figures, starter code, obsolete/older versions of code, etc.
• The "...run" folders contains code edited for particular runs.

Notes

• The reason for combining the interferometer's temperature scan code with Bob's intensity modulator code is that as far as I know, it isn't possible to control the same power supply with two separate scripts simultaneously.

Requirements

Mysql

The scripts here store and collect data from mysql tables from local mysql databases. If you don't have mysql installed, you first need to install it (see https://www.mysql.com/downloads/) and create databases, tables, and users. Unless you set up the exact same databases and tables, you will probably have to change the database, table, and column names/specs in the scripts.

Python packages

Below are listed all the packages that are used in this repo. Many may already be installed on your computer, but otherwise you should install them. Some may be redundant.

Python3:

• pymysql
• pyvisa
• serial
• socket
• time
• math
• ThorlabsPM100
  • USBTMC
• matplotlib
  • matplotlib.pyplot
• requests
• ast
• datetime
  • timedelta
• numpy
• getpass
• os
• subprocess
  • Popen
  • PIPE
• sys
• glob
• pipes
  • quote
• argparse

Installation command

To install python packages, use:

• python3 -m pip install --user <package1> <package2> ...

Tips

• If you are using the USBTMC driver to connect to the powermeter (via USB), you may need to first execute the terminal command: sudo chown <username>:<username> /dev/<device folder>
  • You can check for the device folder by executing ls /dev and unplugging/replugging in the USB into the computer.
  • The device folder names are typically named e.g. usbtmc0 or usbtmc1
• For runVapandPOpt1D_noScan.py and runVapandPOpt1D.py, set the voltage ranges for the initial scans to be greater than Vpi to avoid power minima at the endpoints of the scan range
• For runVapandPOpt1D_noScan.py, you are expected to manually find the optimal DC Bias voltage of Bob's IM before starting.

For other tips and useful commands for getting started, see the CQNET repo's README.

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This code was written by Sam Davis at Caltech. Contact me at s1dav1s@alumni.stanford.edu if you have any questions.