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Characterize Quantum-Limited Parametric Amplifier

Note

This tutorial is applicable to all SHFPPC Instruments.

Goals and Requirements

The goal of this tutorial is to demonstrate how to use the SHFPPC and SHFQA or SHFQC to characterize quantum-limited parametric amplifiers using the LabOne Graphical User Interface (GUI). The SHFPPC is used to generate the pump tone signal to drive a quantum-limited parametric amplifier, and the SHFQA or SHFQC is used to generate and acquire the readout signal.

LabOne Q is the recommended control software to operate the SHFPPC and other instruments for Quantum Technology applications.

Preparation

Connect the cables as illustrated in Figure 1. The trigger signal connection is required only when using the SHFPPC Sweeper.

Make sure that the instruments are powered on, warmed up, and connected by Ethernet to your local area network (recommended) where the host computer resides, or by USB cable directly to your host computer. After starting LabOne, the default web browser opens with the LabOne Graphical User Interface.

Figure 1: SHFPPC and SHFQA Connection.

Tutorial

In this tutorial, the Pump Output of the SHFPPC channel 1 is used to generate a pump signal, the Signal Output and Input of the SHFQA channel 1 is used to generate and acquire a readout signal, which is amplified by about 10 dB through the channel 1 Signal Input and Output of the SHFPPC.

For simplicity no qubit system is used in the tutorial, so the Signal Output of the SHFQA channel 1 is connected to the Signal Input of the SHFPPC channel 1.

In case of using the SHFPPC without using the SHFQA or SHFQC, the SHFPPC can be used to generate both pump and probe tone signals on the Pump Output port simultaneously.

The following steps show how to use the LabOne GUI to manually characterize quantum-limited parametric amplifiers by sweeping pump tone frequency and power.

  1. Configure the SHFPPC channel 1

    Configure the Input and Output Tab as shown in Figure 2 and in Table 1, to generate a continuous pump signal with a frequency of 6 GHz and a power of 0 dBm at the Pump Output of the SHFPPC channel 1.

    Figure 2: Configurations of the SHFPPC In/Out Tab.

    Table 1: Settings of Channel 1 on In/Out Tab
    Parameter Setting Description
    Pump Tone On Enabled Enables Pump output.
    ALC Enabled Enables Automatic Level Control (ALC).
    Filter Enabled Enables low-pass filter.
    Frequency (Hz) 6 GHz Sets Pump output frequency.
    Power (dBm) 0 dBm Sets Pump output power.
    Probe Tone On Disabled Disables Probe Tone Output.

  2. Configure the SHFQA channel 1.

    Configure the Input and Output Tab, the QA Setup Tab, and the Scope Tab as shown in the figures below, to generate a continuous readout waveform with a frequency of 5.01 GHz and a power of -16 dBm on the Signal Output of the SHFQA channel 1, and to monitor the input signal on the Signal Input of the SHFQA channel 1. The readout signal generated from the SHFQA is sent to the Signal Input of the SHFPPC channel 1 where the input signal is amplified by about 10 dB, and the signal from the Signal Output of the SHFPPC channel 1 is then acquired and monitored by the SHFQA Scope.

    Figure 3: Configurations of the SHFQA In/Out Tab.

    Figure 4: Configurations of the SHFQA Quantum Analyzer Setup Tab.

    Figure 5: Configurations of the SHFQA Scope Tab.

    Table 2: Settings of QA Channel 1 on In/Out Tab, QA Setup Tab, and Scope Tab.
    Parameter Setting Description
    In/Out Tab    
    Signal Input On Enabled Enables Signal Input 1.
    Signal Input Power Range (dBm) -10 dBm Sets signal input power range to -10 dBm
    Input Path RF Sets signal input path to RF path.
    Input Center Freq (Hz) 5 GHz Sets input center frequency to 5 GHz.
    Signal Output On Enabled Enables Signal Output.
    Signal Output Power Range -20 dBm Sets signal output power range to -20 dBm.
    Output Path RF Sets Signal Output path to RF path.
    Signal Output Center Freq (Hz) 5 GHz Sets signal output center frequency. The center frequencies of signal input and output are the same if configured the input and output paths are the same.
    Quantum Analyzer Setup Tab    
    Application Mode Spectroscopy Sets application mode to Spectroscopy.
    Power Spectral Density Disabled Disables the Power Spectral Density measurement mode.
    Offset Freq (Hz) 10 MHz Sets frequency of the digital oscillator.
    Amplitude 0.5 Sets dimensionless amplitude of the digital oscillator.
    Waveform Mode Continuous Sets waveform mode to continuous, so the instrument generates continuous waveform on the output.
    Scope Tab
    Run/Stop Enabled Runs the Scope.
    Horizontal Mode Freq FFT Sets horizontal mode to FFT.
    Vertical Channel 1 Select Signal Input 1 Selects Signal Input 1 on Scope channel 1 to monitor the input signal.
    Vertical Channel 1 On Enabled Enables Scope channel 1. Remains the rest of the Scope channels Disabled.
    HW Averaging Disabled Disables the hardware averaging.
    Averaging Filter Disabled Disables averaging filter.
    Scope Display On Selects Scope display.
    Scope Math Add Added peak position search Adds measurement tool to search peak position of the monitored data.

  3. Manually sweeping pump tone parameters to characterize the quantum-limited parametric amplifier

    A simple characterization of quantum-limited parametric amplifiers can be done by monitoring the amplitude of the readout input signal on the SHFQA Scope while manually sweeping pump frequency and power. To measure the signal-to-noise ratio of a readout signal at fixed pump frequency and pump power, please refer to the tutorial Power Spectrum Density Measurement of the SHFQA.