QCM-RF
Description
The RF Qubit Control Module (QCM-RF) is an instrument completely dedicated to qubit control using parametrized pulses. The front of a QCM-RF module is presented below:
On the front of a QCM-RF module you will find the following components:
2 x SMA male connectors: 2 outputs (O[1-2] @ 50 Ω)
2 x SMP female connectors: Marker output channels (0-3.3 V TTL).
6 x status LEDs: See section Frontpanel LEDs for details.
The pulses generated by the QCM-RF are stored as waveform envelopes in memory and can be parametrized by changing gain and offset and additionally phase, if also modulated. This parametrization is controlled by the AWG paths of the Q1 sequencer (Description), which each have two waveform paths (from here on referred to as path 0 and 1). Using parametrization, the output of these paths can be operated as modulated IQ signals, which are connected directly to the onboard IQ mixers. The two paths of each sequencer can, in turn, be connected to any output of the instrument (i.e. O1 and O2). Additionally, the sequencers also control two marker output channels. The RF version of the QCM has two IQ mixers on-board for generating signals at its outputs in the range of 2-18.5GHz.
For a list of available features please go to Features
For an overview of applications please go to Applications
Block Diagram
Features
1. 10MHz Reference
Alongside all modules available, the QCM-RF module operates with respect to a 10MHz reference provided by the cluster.
2. Trigger
The trigger of the QCM-RF is connected to the cluster and allows for fast synchronization between modules.
3. SYNQ
The Qblox SYNQ technology enables simple and quick synchronization over multiple instruments, allowing for modules to be started synchronously << 1ns. See section Synchronization for more information.
4. LINQ
The Qblox LINQ technology allows for the results of measurements to be shared between devices, distributing outcomes in < 320ns.
5. Q1 Sequencers
The Q1 sequencers are the heart(s) of the QCM-RF instrument. They orchestrate the experiment using a custom low-latency sequence processor specifically designed for quantum experiments. Each Q1 sequencer controls a dedicated AWG path and, in the case of a QCM/QCM-RF, an acquisition path, which enables parametrized pulse generation and readout. Each instrument has 6 of these sequencers to target multiple qubits with one instrument. See section Q1 Sequence Processor for more information on how to program and control them.
Each sequencer has a dedicated gain step for both path 0 and 1, which can be
statically configured using the Sequencer.gain_awg_path0() parameters.
However, the gain can also be dynamically controlled using the set_awg_gain
instruction of the sequence processor which enables pulse parametrization
(see section Instructions). The static and
dynamic gain controls are complementary.
Note
If modulated IQ signals are used for an output pair, the gain
Sequencer.gain_awg_path0() has to be the same for both paths.
Each sequencer has a dedicated numerically controlled oscillator. The NCO can be used to track the qubit phase (at a fixed frequency) and the IQ mixer can be used to modulate the output.
The frequency of the NCO and phase can be statically controlled using the
Sequencer.nco_freq() and Sequencer.nco_phase_offs()
parameters. However, the phase of the NCO can also be dynamically controlled
using the set_freq, reset_ph, set_ph and set_ph_delta instructions of
the sequence processor, which enables
pulse parametrization and execution of virtual Z-gates (see section
Instructions). The static and dynamic phase
control
is complementary. The modulation is enabled using the
Sequencer.mod_en_awg() parameter. The demodulation is enabled using
the Sequencer.demod_en_acq() parameter.
Each sequencer has the ability to perform averaging and binning of measurement of results. Integration and state assignment of data can also be performed on board, outcomes of these measurements can then be shared via LINQ within 200ns.
6. Marker output channels
Each sequencer has control over the four marker output channels, with the
control of each sequencer being OR’ed to create the final marker outputs.
The markers can be dynamically controlled with the set_mrk instruction of the
sequence processor (see section Instructions),
but can also be overwritten with the static marker overwrite parameters
Sequencer.marker_ovr_en() and Sequencer.marker_ovr_value().
The marker output range is 0-3.3 V TTL. In the QCM-RF module set_mrk is also used
to toggle the switches before the outputs to enable the respective
output.
For the QCM-RF module, bit indices 0 & 1 correspond to output enable 1 and 2 respectively,
indices 2 & 3 correspond to marker outputs 2 and 1 respectively.
6.1 Setting Markers as Active HIGH/LOW
The default state of marker is active high (OFF = 0V, ON = 3.3V). Users
have the ability to change the marker output from active HIGH to active LOW ( OFF = 3.3 V, ON = 0V). It can be done
using the parameter QCM_RF.marker0_inv_en(). This inversion of marker default states is possible for all marker
channels. Here marker0 and marker1 correspond to bit indices 3 & 2 respectively in the argument of
set_mrk as mentioned above.
7. Sequencer multiplexer
A multiplexer that allows any sequencer to be connected to any output. Multiple sequencers can also be connected to a single output. This, in combination with the dedicated NCO per sequencer and IQ mixer per output, enables easy and flexible targeting of multiple qubits on a single channel. See Multiplexing for more details.
Note
The output of each sequencer is complimentary. Be aware of potential output clipping when connecting multiple sequencers to a single output.
1. Digital Offset
Each sequencer has a dedicated offset step for both path 0 and 1, which can be
statically configured using the Sequencer.offset_awg_path0() parameters.
However, the offset can also be dynamically controlled using the set_awg_offs
instruction of the sequence processor which enables pulse parametrization.
(see section Instructions). The static and
dynamic offset controls are complementary.
Note
This offset is applied to the signals before the mixer and cannot be used for DC offset correction if the mixer is enabled.
9. DAC
The dynamic output range of the QCM-RF’s DACs is 1 Vpp and 50 Ω terminated at 1GBps.
10. Offset DAC
The offset DAC allows users to apply a DC offset to the output signal without the risk of clipping the signal at the DAC.
11. Local Oscillator
The QCM-RF module comes equipped with built-in independent local oscillators for each output capable of generating signals between 2.5 and 18GHz for IQ mixing.
12. IQ Mixer
The QCM-RF module also has onboard IQ mixers for the output. The LO’s of these internal mixing stages are capable of sweeping between 2-18.5GHz. This allows for the generation of signals at the qubit frequency.
13. Variable Attenuator
The QCM-RF module has variable attenuators on both the output terminals. These attenuators can be programmed from 0 to 60dB in 2dB increments.
14. Output Switch
The output terminal of the QCM-RF can be toggled with an inbuilt switch, which can also be controlled dynamically with the Q1 processor.
Applications
The RF Qubit control module is designed to be utilized for the control of qubits. The experimental setup will vary depending on the device being controlled:
Superconducting Qubits
The QCM-RF can be utilized to generate superconducting qubit drive frequencies. As the QCM-RF module has onboard IQ mixers for the generation of pulses it can interface directly with the drive lines of the qubits. The details of such a setup are provided here: Superconducting Qubits.
Spin Qubits
The QCM-RF module can be used to generate control signals for GaAs, Si and Ge spin qubits. As the QCM-RF module has on-board IQ mixers for the generation of pulses it can synthesize control pulses directly at the qubit frequency with no need for external RF mixing circuitry. Details of potential setups and applications are available here: Spin Qubits.
NV-centers/Spins in Diamonds
The QCM-RF module can be used to generate control pulses for spins in diamond. As the QCM-RF module has on-board IQ mixers for the generation of pulses it can synthesize control pulses directly at the qubit frequency with no need for external RF mixing circuitry. Details of potential setups and applications are available here: NV-centers.
Specifications
Output
Parameter |
Condition |
Min |
Typ |
Max |
|---|---|---|---|---|
Number of channels |
2 |
|||
Output coupling |
AC |
|||
DAC resolution |
16bits |
|||
Output impedance |
50Ω |
|||
Output power |
In 50Ω load |
-55dBm |
5dBm |
Marker Outputs
Parameter |
Condition |
Min |
Typ |
Max |
|---|---|---|---|---|
Number of markers |
4 |
|||
High voltage |
high Z load |
3.3V |
||
Low voltage |
0.0V |