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Arbitrary Wave Generator (AWG)

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syue99 edited this page Aug 24, 2022 · 26 revisions

Introduction

An arbitrary wave generator (AWG) is a key part of our experiment, especially for quantum gate operations. Here at NYU we use Keysight M3201A and Keysight M3201A for our AWG card and this server (keysight_awg) is thus implemented for these two AWG cards. The AWG is used in a similar way as a DDS, as we use it to control the analog signals of our experiment (mainly to AOMs and then modulate our laser light). But the difference between a DDS and an AWG is that it can take in an array of time-series data and output exactly what the array specifies with a time resolution of 1 or 2 ns. On the other hand, a DDS usually takes in inputs of frequency domain parameters such as a frequency, an amplitude, and a phase and outputs a sinewave with these parameters. So an AWG can have more degrees of freedom and is especially helpful when we need complicated pulses that modulate multiple frequencies together (e.g. a Molmer-Sorensen gate).

Running the server

There are multiple ways of running LabRAD server. The easiest is to run this python script itself. At the end of this script, you will see

if __name__ == "__main__":
    from labrad import util
    util.runServer( Keysightawg() )

So if you run this script in the command_line like python PATH-TO\servers\control_instruments\awg\keysightawg.py it will run this chunk of code.

keysight_awg Server

Similar to most other labrad servers, the awg server also calls the python API given by the manufacturer of the instrument (Keysight SD1) to realize different functions we need. Given the complicated configurations of an awg card, we will give a brief introduction to the AWG hardware, and the corresponding API respectively. We then talk about the functions of the awg server in detail.

Keysight AWG

Hardware Structure and Output modes

As shown by the figure below, a keysight AWG card has four channels of output. Every output channel consists of a function generator (sine wave, square wave, triangular wave) and an awg generator, and these two generators can either be used separately or together via a fancy digital mixer. AWG As a result, the awg card supports the following output modes:

  1. Function generator (FG) output
  2. AWG direct output
  3. Amplitude modulation output (use FG for the carrier signal and use AWG for the amplitude)
  4. Phase modulation output (Similar to 3, not used by us)
  5. IQ modulation output (use FG for the carrier and two AWGs for the modulation)

We use 1,2,3,5 on our servers. If you want to learn more about how these modulations work, feel free to check out the Keysight user manual section 1.2 9018-04448.pdf.

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