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EPJ Quantum Technology

An open-source FPGA control architecture for solid-state spin-photon interfaces

Jae-Pil Park, Changhoon Park, Minseok Jeon, Yong Soo Lee, Yeeun Choi, Yong-gwon Kim, Nu‐Ri Park, Il‐Young Kim, Seok‐Kyun Son, Chulki Kim, Seung-Woo Jeon, Sang-Wook Han, Dongyeon Daniel Kang

Published Aug 14, 2026• 0 citations
Publisher

Abstract

Scalable quantum networks require quantum interfaces that coherently connect stationary matter qubits with flying photonic qubits. In solid-state defect platforms, such interfaces require coordinated optical excitation, microwave spin control, photon detection, and feedback with nanosecond-level timing, while conventional instrument-based control systems become increasingly difficult to scale as experimental protocols grow in complexity. Here we present an open-source FPGA control architecture for solid-state spin–photon interface experiments. Built on the Quantum Instrumentation Control Kit (QICK), the platform extends the existing FPGA overlay by integrating a programmable multi-channel single-photon counter, enabling photon-count–centric experiment execution while preserving compatibility with the QICK software ecosystem. This architecture integrates time-gated single-photon detection with synchronized RF, microwave, and digital control within a unified hardware environment. Using single nitrogen-vacancy (NV) centers in diamond, we experimentally validate the platform through microwave spin manipulation, resonant optical control, automated measurement routines, and time-bin–encoded spin–photon correlation protocols relevant to quantum networking. These results establish an extensible and experimentally validated control framework for solid-state spin–photon interfaces, with clear potential to accelerate the development of scalable quantum-network nodes.

DOI
10.1140/epjqt/s40507-026-00555-2

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Scalable quantum networks require quantum interfaces that coherently connect stationary matter qubits with flying photonic qubits. In solid-state defect platforms, such interfaces require coordinated optical excitation, microwave spin control, photon detection, and feedback with nanosecond-level timing, while conventional instrument-based control systems become increasingly difficult to scale as experimental protocols grow in complexity. Here we present an open-source FPGA control architecture for solid-state spin–photon interface experiments. Built on the Quantum Instrumentation Control Kit (QICK), the platform extends the existing FPGA overlay by integrating a programmable multi-channel single-photon counter, enabling photon-count–centric experiment execution while preserving compatibility with the QICK software ecosystem. This architecture integrates time-gated single-photon detection with synchronized RF, microwave, and digital control within a unified hardware environment. Using single nitrogen-vacancy (NV) centers in diamond, we experimentally validate the platform through microwave spin manipulation, resonant optical control, automated measurement routines, and time-bin–encoded spin–photon correlation protocols relevant to quantum networking. These results establish an extensible and experimentally validated control framework for solid-state spin–photon interfaces, with clear potential to accelerate the development of scalable quantum-network nodes.
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Quantum information communication, sensing, and computation often require complex and expensive instrumentation resulting in a large entry barrier. The Quantum Instrumentation Control Kit (QICK) overcomes this barrier for superconducting qubits with a collection of software and firmware for state-of-the-art radio frequency system on chip (RFSoC's) field programmable gate architecture (FPGA) chips. Here we present a software and firmware extension to QICK, the Quantum Instrumentation Control Kit - Defect Arbitrary Waveform Generator (QICK-DAWG), which is an open-source software and firmware package that supports full quantum control and measurement of nitrogen-vacancy defects in diamond and other quantum defects using RFSoC FPGAs. QICKDAWG extends QICK to the characterization of nitrogen-vacancy defects and other diamond quantum defects by implementing DC-1 GHz readout, AOM or gated laser control, and analog or photon counting readout options. QICK-DAWG also adds pulse sequence programs and data analysis scripts to collect and characterize photoluminescence (PL) intensity, optically detected magnetic resonance (ODMR) spectra, PL readout windows, Rabi oscillations, Ramsay interference spectra, Hahn echo spin-spin relaxation times T2_22​, and spin-lattice relaxation times T1_11​. We demonstrate that QICK-DAWG is a powerful new paradigm of open source quantum hardware that significantly lowers the entry barrier and cost for quantum sensing using quantum defects.
As quantum computing continues to progress, there is an increasing need for standardized quantum network technology [1], [2] to connect quantum computers together. Experimental testbeds are necessary in order to develop quantum network software and hardware. Building a scalable testbed for data center-level quantum networks requires overcoming numerous engineering and technical challenges in quantum communications, quantum processing and quantum storage. In this work, we describe a software framework for use with an all-photonic quantum networking testbed. This framework is designed for rapid development and capable of automated execution of quantum experiments. We introduce PnPQ, an open-source, unified driver library for hardware commonly used in quantum optical experiments. On top of this low-level hardware control library, we present software modules for controlling and coordinating quantum network nodes using remote procedure calls (RPC). Finally, we describe high-level software for performing and analyzing quantum photonic experiments using these software modules. As a whole, these software components comprise the first version of a framework that will enable us to implement and test quantum network architectures. This framework is intended to help us move forward from building simple experiments to complex Quantum systems.
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.