We report a synchronized time tagger based on a field-programmable-gate-array chip for one- or two-dimensional quantum experiments that require precise single-photon detections. The time tagger has a 9.2 ps single-shot root-mean-square precision and is equipped with a 1 GB dynamic memory for data storage. Because the relationship between the control parameter and acquired data is guaranteed by using hardware synchronization, the experiment can be performed much faster than conventional schemes that are based on software synchronization. With this technique, an improvement of up to 61.3% in efficiency is observed in a typical nitrogen-vacancy center quantum experiment. We further show advanced optical features of the center using the detected high-resolution photon-arrival information and provide detailed electrical benchmarking of the device. This technique could be easily extended to other quantum control systems.
We report a synchronized time tagger based on a field-programmable-gate-array chip for one- or two-dimensional quantum experiments that require precise single-photon detections. The time tagger has a 9.2 ps single-shot root-mean-square precision and is equipped with a 1 GB dynamic memory for data storage. Because the relationship between the control parameter and acquired data is guaranteed by using hardware synchronization, the experiment can be performed much faster than conventional schemes that are based on software synchronization. With this technique, an improvement of up to 61.3% in efficiency is observed in a typical nitrogen-vacancy center quantum experiment. We further show advanced optical features of the center using the detected high-resolution photon-arrival information and provide detailed electrical benchmarking of the device. This technique could be easily extended to other quantum control systems.
We discuss custom time-tagging instrumentation for high-speed single-photon metrology, focusing particularly on implementations that can tag and process detection events from multiple single-photon detectors with sub-nanosecond timing resolution and at detection rates above 100 MHz. The systems we present view the detector signal as if it were a serial data stream, tagging events according to the bit period in which a rising edge from the detector occurs. We achieve sub-nanosecond resolution with serial data receivers operating up to 10 Gb s −1 . Data processing bottlenecks are avoided with pipelined algorithms and controlled data flow implemented in field-programmable gate arrays.
Abstract Photonic quantum technology requires precise, time-resolved identification of photodetection events. In distributed quantum networks with spatially separated and drifting time references, achieving high precision is particularly challenging. Here we build on recent advances of using single-photons for time transfer and employ and quantify a fast postprocessing scheme designed to pulsed single-photon sources. We achieve an average root mean square synchronization jitter of 3.0 ps. The stability is comparable to systems with Rb vapor cell clocks with 19 ps at 1 s integration time, in terms of Allan time deviation. Remarkably, our stability is even better than classical high-precision time transfer, like the White Rabbit protocol, although we use significantly less signal (single-photon level). Our algorithms allow local processing of the data and do not affect the secure key rate. It compensates substantial clock imperfections from crystal oscillators and we foresee great potential for low signal scenarios. The findings are naturally suited to quantum communication networks and provide simultaneous time transfer without adding hardware or modifying the single-photon sources.
Precise time synchronization is a fundamental challenge in distributed quantum systems, with direct implications for secure communication, sensing, and next-generation network technologies. In this study, we present a Field Programmable Gate Array (FPGA)-based implementation of a Time-Correlated Entangled Photons (TCEP) source-based synchronization system, achievingsub-nanosecondaccuracy with timing jitter consistently below 200 ps for a distance up to 20 km. The system leverages the strong temporal correlations inherent in entangled photon pairs to compute synchronization offsets between spatially separated nodes. The design features a modular architecture with optimized kernels for temporal correlation, data aggregation, and normalization, enabling efficient resource utilization and high-throughput performance. Experimental validation demonstrates the FPGA's ability to process photon timestamp data and compute cross-correlation functions significantly faster than traditional CPU-based approaches, achieving execution times in the millisecond range even for large datasets. Our FPGA implementation achieved a consistent$\sim$800 times speedup over CPU, with performance largely unaffected by channel length. Resource utilization analysis highlights the scalability of the design, with the fully integrated system operating at a clock frequency of 397.5 MHz while maintaining efficient use of logic elements, registers, and memory blocks. This hardware-efficient approach provides the timing backbone for next-generation technologies, facilitating advancements in ultra-reliable low-latency communication, distributed quantum computing, quantum-enhanced sensing, navigation, and lays a foundation for forthcoming 6G networks and the quantum internet.
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.
Abstract This paper presents a correlator for constructing the second-order autocorrelation function g(2)(τ), implemented on a field-programmable gate array (FPGA). The device is designed for high-precision recording of time intervals between photons detected from single emitters. The use of an FPGA makes it possible to achieve a time resolution of 185 ps and real-time event processing. Experimental data confirming the achievement of photon antibunching with g(2)(0) < 0.5, characteristic of single quantum emitters, are demonstrated. The device can be used to analyze photon correlations in quantum optics problems and when working with single quantum emitters.
A correlator for constructing the second-order autocorrelation function g(2)(τ) implemented on a field-programmable gate array (FPGA) is presented. The device is intended for high-precision recording of time intervals between photons emitted by single emitters. Using an FPGA made it possible to achieve a temporal resolution of 185 ps and real-time event processing. Experimental data confirming the achievement of photon antibunching with g(2)(0) < 0.5, which is typical for single quantum emitters, are demonstrated. The device can be used for analyzing photon correlations in tasks of quantum optics and when working with single quantum emitters.