arXiv:2112.02933 · Review of Scientific Instruments
ICARUS-Q: Integrated control and readout unit for scalable quantum processors
Kun Hee Park, Yung Szen Yap, Yuanzheng Paul Tan, Christoph Hufnagel, Long Hoang Nguyen, Karn Hwa Lau, Patrick Bore, Stavros Efthymiou, Stefano Carrazza, Rangga P. Budoyo, Rainer Dumke
We present a control and measurement setup for superconducting qubits based on the Xilinx 16-channel radio-frequency system-on-chip (RFSoC) device. The proposed setup consists of four parts: multiple RFSoC boards, a setup to synchronize every digital to analog converter (DAC) and analog to digital converter (ADC) channel across multiple boards, a low-noise direct current supply for tuning the qubit frequency, and cloud access for remotely performing experiments. We also designed the setup to be free of physical mixers. The RFSoC boards directly generate microwave pulses using sixteen DAC channels up to the third Nyquist zone, which are directly sampled by its eight ADC channels between the fifth and the ninth zones.
We present a control and measurement setup for superconducting qubits based on the Xilinx 16-channel radio-frequency system-on-chip (RFSoC) device. The proposed setup consists of four parts: multiple RFSoC boards, a setup to synchronize every digital to analog converter (DAC) and analog to digital converter (ADC) channel across multiple boards, a low-noise direct current supply for tuning the qubit frequency, and cloud access for remotely performing experiments. We also designed the setup to be free of physical mixers. The RFSoC boards directly generate microwave pulses using sixteen DAC channels up to the third Nyquist zone, which are directly sampled by its eight ADC channels between the fifth and the ninth zones.
This thesis presents the development of a superconducting qubit control and readout system based on FPGA technology, with a focus on the design of a pulse sequencer and the integration of frequency-multiplexed control. The system leverages the Quantum Instrumentation Control Kit (QICK), an open-source Xilinx RFSoC-based platform capable of direct digital synthesis and acquisition of microwave signals up to 10 GHz. The QICK firmware was extended to support the simultaneous generation and readout of multiple frequency-multiplexed tones, enabling the control and measurement of several qubits coupled to a shared feedline. This approach optimizes the number of controllable qubits relative to the available ADC and DAC resources on the RFSoC 4x2 board. Furthermore, this work includes the development of Qubase, a Python-based pulse sequencer that allows users to easily define and execute complex sequences of control and measurement pulses through the QICK Python interface. The resulting architecture is both flexible and scalable, providing a foundation for efficient multi-qubit experiments and enabling advanced techniques such as quantum error correction and real-time feedback.
We introduce a Xilinx RF System-on-Chip (RFSoC)-based qubit controller (called the Quantum Instrumentation Control Kit, or QICK for short), which supports the direct synthesis of control pulses with carrier frequencies of up to 6 GHz. The QICK can control multiple qubits or other quantum devices. The QICK consists of a digital board hosting an RFSoC field-programmable gate array, custom firmware, and software and an optional companion custom-designed analog front-end board. We characterize the analog performance of the system as well as its digital latency, important for quantum error correction and feedback protocols. We benchmark the controller by performing standard characterizations of a transmon qubit. We achieve an average gate fidelity of Favg=99.93%. All of the schematics, firmware, and software are open-source.
We have developed an electronic hardware system for the control and readout of multi-superconducting qubit devices. The hardware system is based on the design ideas of good scalability, high synchronization and low latency. The system, housed inside a VPX-6U chassis, includes multiple arbitrary-waveform generator (AWG) channels, analog-digital-converter (ADC) channels as well as direct current source channels. The system can be used for the control and readout of up to twelve superconducting transmon qubits in one chassis, and control and readout of more and more qubit can be carried out by interconnecting the chassis. By using field programmable gate array (FPGA) processors, the system incorporates three features that are specifically useful for superconducting qubit research. Firstly, qubit signals can be processed using the on-board FPGA after being acquired by ADCs, significantly reducing data processing time and data amount for storage and transmission. Secondly, different output modes, such as direct output and sequential output modes, of AWG can be implemented with pre-encoded FPGA. Thirdly, with data acquisition ADCs and controlAWGs jointly controlled by the same FPGA, the feedback latency can be reduced, and in ourtest a 178.4 ns latency time is realized. This is very useful for future quantum feedback experiments. Finally, we demonstrate the functionality of the system by applying the system to the control and readout of a 10 qubit superconducting quantum processor.
Control electronics for superconducting quantum processors have strict requirements for accurate command of the sensitive quantum states of their qubits. Hinging on the purity of ultra-phase-stable oscillators to upconvert very-low-noise baseband pulses, conventional control systems can become prohibitively complex and expensive when scaling to larger quantum devices, especially as high sampling rates become desirable for fine-grained pulse shaping. Few-gigahertz radio-frequency (RF) digital-to-analog converters (DACs) present a more economical avenue for high-fidelity control while simultaneously providing greater command over the spectrum of the synthesized signal. Modern RF DACs with extra-wide bandwidths are able to directly synthesize tones above their sampling rates, thereby keeping the system clock rate at a level compatible with modern digital logic systems while still being able to generate high-frequency pulses with arbitrary profiles. We have incorporated custom superconducting qubit control logic into off-the-shelf hardware capable of low-noise pulse synthesis up to 7.5 GHz using an RF DAC clocked at 5 GHz. Our approach enables highly linear and stable microwave synthesis over a wide bandwidth, giving rise to high-resolution control and a reduced number of required signal sources per qubit. We characterize the performance of the hardware using a five-transmon superconducting device and demonstrate consistently reduced two-qubit gate error (as low as 1.8%), which we show results from superior control chain linearity compared to traditional configurations. The exceptional flexibility and stability further establish a foundation for scalable quantum control beyond intermediate-scale devices.
Advanced quantum physics experiments place strict demands on control electronics, including phase-coherent multichannel RF/microwave generation, precise timing synchronization, low-latency response, and simultaneous support for wideband and near-DC signal processing. Existing control platforms often face trade-offs between channel count, integration level, and real-time performance, limiting scalability and experimental flexibility. In this work, we present a highly integrated real-time control system based on an XCZU49DR RFSoC. The platform integrates up to 16 RF DAC channels (9.85 GSa/s) and 16 RF ADC channels (2.5GSa/s) on a single chip, enabling synchronous multichannel signal generation and acquisition with deterministic timing. A custom RF front-end supports both broadband RF operation and low-frequency signal conditioning, while on-chip digital up/down conversion and programmable logic enable flexible waveform synthesis and real-time data processing. Performance characterization shows clean RF and microwave generation with spurious components suppressed below −59.0dBm at 200MHz and below −62.6dBm at 2.9GHz, while phase noise reaches −120.0dBc/Hz and −96.9dBc/Hz at 1kHz offset for 200MHz and 2.9GHz carriers, respectively, confirming low-noise and phase-coherent operation over a wide frequency range. The proposed platform provides a compact, scalable, and reconfigurable solution for quantum control and precision measurement. It is currently being applied to experiments involving NV centers and trapped ions, and can be readily adapted to other quantum systems, offering a practical foundation for next-generation
We describe a digital microwave platform called Presto, designed for measurement and control of multiple quantum bits (qubits) and based on the third-generation radio-frequency system on a chip. Presto uses direct digital synthesis to create signals up to 9 GHz on 16 synchronous output ports, while synchronously analyzing responses on 16 input ports. Presto has 16 DC-bias outputs, four inputs and four outputs for digital triggers or markers, and two continuous-wave outputs for synthesizing frequencies up to 15 GHz. Scaling to a large number of qubits is enabled through deterministic synchronization of multiple Presto units. A Python application programming interface configures a firmware for synthesis and analysis of pulses, coordinated by an event sequencer. The analysis integrates template matching (matched filtering) and low-latency (184-254 ns) feedback to enable a wide range of multi-qubit experiments. We demonstrate Presto's capabilities with experiments on a sample consisting of two superconducting qubits connected via a flux-tunable coupler. We show single-shot readout and active reset of a single qubit; randomized benchmarking of single-qubit gates showing 99.972% fidelity, limited by the coherence time of the qubit; and calibration of a two-qubit iSWAP gate.