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It is the source and foundation of lingnan traditional culture to reconstruct the cultural value of lingnan traditional villages, reflect the changes and development of Lingnan region, and truly record the agricultural ecology, architectural heritage and folk art of lingnan traditional villages. It is a key step to revitalize lingnan rural culture. Influenced by globalization, the traditional village culture in Lingnan is faced with the problems of otherization and homogenization. In order to fundamentally solve the problem, this article from the perspective of philosophical speculations of authentic, new and practical three levels to explore the value of lingnan traditional village culture reconstruction, more deeply, to grasp the essence of lingnan traditional village culture development, to protect the cultural original features, innovation activation folk crafts and building community, regional culture of lingnan traditional village culture unique charm.

Although near-term quantum computing devices are still limited by the quantity and quality of qubits in the so-called NISQ era, quantum computational advantage has been experimentally demonstrated. Moreover, hybrid architectures of quantum and classical computing have become the main paradigm for exhibiting NISQ applications, where low-depth quantum circuits are repeatedly applied. In order to further scale up the problem size solvable by the NISQ devices, it is also possible to reduce the number of physical qubits by "cutting"the quantum circuit into different pieces. In this work, we experimentally demonstrated a circuit-cutting method for simulating quantum circuits involving many logical qubits, using only a few physical superconducting qubits. By exploiting the symmetry of linear-cluster states, we can estimate the effectiveness of circuit-cutting for simulating up to 33-qubit linear-cluster states, using at most 4 physical qubits for each subcircuit. Specifically, for the 12-qubit linear-cluster state, we found that the experimental fidelity bound can reach as much as 0.734, which is about 19% higher than a direct implementation on the same 12-qubit superconducting processor. Our results indicate that circuit-cutting represents a feasible approach of simulating quantum circuits using much fewer qubits, while achieving a much higher circuit fidelity.

Quantum walks are the quantum mechanical analogue of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8x8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high fidelity single and two particle quantum walks. Furthermore, with the high programmability of the quantum processor, we implemented a Mach-Zehnder interferometer where the quantum walker coherently traverses in two paths before interfering and exiting. By tuning the disorders on the evolution paths, we observed interference fringes with single and double walkers. Our work is an essential milestone in the field, brings future larger scale quantum applications closer to realization on these noisy intermediate-scale quantum processors., 13 pages, 4 figures, and supplementary materials with 21 pages, 13 figures and 1 table

Quantum error correction is an essential ingredient for universal quantum computing. Despite tremendous experimental efforts in the study of quantum error correction, to date, there has been no demonstration in the realisation of universal quantum error-correcting code, with the subsequent verification of all key features including the identification of an arbitrary physical error, the capability for transversal manipulation of the logical state and state decoding. To address this challenge, we experimentally realise the [5, 1, 3] code, the so-called smallest perfect code that permits corrections of generic single-qubit errors. In the experiment, having optimised the encoding circuit, we employ an array of superconducting qubits to realise the [5, 1, 3] code for several typical logical states including the magic state, an indispensable resource for realising non-Clifford gates. The encoded states are prepared with an average fidelity of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$57.1(3)\%$\end{document} while with a high fidelity of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$98.6(1)\%$\end{document} in the code space. Then, the arbitrary single-qubit errors introduced manually are identified by measuring the stabilisers. We further implement logical Pauli operations with a fidelity of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$97.2(2)\%$\end{document} within the code space. Finally, we realise the decoding circuit and recover the input state with an overall fidelity of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$74.5(6)\%$\end{document}, in total with 92 gates. Our work demonstrates each key aspect of the [5, 1, 3] code and verifies the viability of experimental realisation of quantum error-correcting codes with superconducting qubits., Experimental demonstration of encoding, decoding, logical operation, and error detection of a five-qubit error correcting code on a superconducting quantum processor.

This paper presents several component prototypes towards a low-latency, small-form-factor optical link designed for the ATLAS Liquid Argon Calorimeter Phase-I trigger upgrade. A prototype of the custom-made dual-channel optical transmitter module, the Miniature optical Transmitter (MTx), with separate transmitter optical sub-assemblies (TOSAs) has been demonstrated at data rates up to 8 Gbps per channel. A Vertical-Cavity Surface-Emitting Laser (VCSEL) driver ASIC has been developed and is used in the current MTx prototypes. A serializer ASIC prototype, operating at up to 8 Gbps per channel, has been designed and tested. A low-latency, low-overhead encoder ASIC prototype has been designed and tested. The latency of the whole link, including the transmitter latency and the receiver latency but not the latency of the fiber, is estimated to be less than 57.9 ns. The size of the MTx is 45 mm x 15 mm x 6 mm., 12 pages, 13 figures

Quantum error correction is a critical technique for transitioning from noisy intermediate-scale quantum (NISQ) devices to fully fledged quantum computers. The surface code, which has a high threshold error rate, is the leading quantum error correction code for two-dimensional grid architecture. So far, the repeated error correction capability of the surface code has not been realized experimentally. Here, we experimentally implement an error-correcting surface code, the distance-3 surface code which consists of 17 qubits, on the \textit{Zuchongzhi} 2.1 superconducting quantum processor. By executing several consecutive error correction cycles, the logical error can be significantly reduced after applying corrections, achieving the repeated error correction of surface code for the first time. This experiment represents a fully functional instance of an error-correcting surface code, providing a key step on the path towards scalable fault-tolerant quantum computing.

Quantum machine learning is expected to be one of the first practical applications of near-term quantum devices. Pioneer theoretical works suggest that quantum generative adversarial networks (GANs) may exhibit a potential exponential advantage over classical GANs, thus attracting widespread attention. However, it remains elusive whether quantum GANs implemented on near-term quantum devices can actually solve real-world learning tasks. Here, we devise a flexible quantum GAN scheme to narrow this knowledge gap, which could accomplish image generation with arbitrarily high-dimensional features, and could also take advantage of quantum superposition to train multiple examples in parallel. For the first time, we experimentally achieve the learning and generation of real-world hand-written digit images on a superconducting quantum processor. Moreover, we utilize a gray-scale bar dataset to exhibit the competitive performance between quantum GANs and the classical GANs based on multilayer perceptron and convolutional neural network architectures, respectively, benchmarked by the Fr\'echet Distance score. Our work provides guidance for developing advanced quantum generative models on near-term quantum devices and opens up an avenue for exploring quantum advantages in various GAN-related learning tasks., Comment: This work was completed in 2019, and the first version of manuscript was submitted to the journal in January 2020

Periodically driven systems, or Floquet systems, exhibit many novel dynamics and interesting out-of-equilibrium phases of matter. Those phases arising with the quantum systems' symmetries, such as global $U(1)$ symmetry, can even show dynamical stability with symmetry-protection. Here we experimentally demonstrate a $U(1)$ symmetry-protected prethermal phase, via performing a digital-analog quantum simulation on a superconducting quantum processor. The dynamical stability of this phase is revealed by its robustness against external perturbations. We also find that the spin glass order parameter in this phase is stabilized by the interaction between the spins. Our work reveals a promising prospect in discovering emergent quantum dynamical phases with digital-analog quantum simulators., 14 pages, 4 figures, and supplementary materials

We experimentally study the ergodic dynamics of a 1D array of 12 superconducting qubits with a transverse field, and identify the regimes of strong and weak thermalization with different initial states. We observe convergence of the local observable to its thermal expectation value in the strong-thermalizaion regime. For weak thermalization, the dynamics of local observable exhibits an oscillation around the thermal value, which can only be attained by the time average. We also demonstrate that the entanglement entropy and concurrence can characterize the regimes of strong and weak thermalization. Our work provides an essential step towards a generic understanding of thermalization in quantum systems., Comment: 6+6 pages, 4+8 figures

Scaling up to a large number of qubits with high-precision control is essential in the demonstrations of quantum computational advantage to exponentially outpace the classical hardware and algorithmic improvements. Here, we develop a two-dimensional programmable superconducting quantum processor, Zuchongzhi, which is composed of 66 functional qubits in a tunable coupling architecture. To characterize the performance of the whole system, we perform random quantum circuits sampling for benchmarking, up to a system size of 56 qubits and 20 cycles. The computational cost of the classical simulation of this task is estimated to be 2-3 orders of magnitude higher than the previous work on 53-qubit Sycamore processor [Nature 574, 505 (2019)NATUAS0028-083610.1038/s41586-019-1666-5. We estimate that the sampling task finished by Zuchongzhi in about 1.2 h will take the most powerful supercomputer at least 8 yr. Our work establishes an unambiguous quantum computational advantage that is infeasible for classical computation in a reasonable amount of time. The high-precision and programmable quantum computing platform opens a new door to explore novel many-body phenomena and implement complex quantum algorithms.

Quantum walks are the quantum analogs of classical random walks, which allow for the simulation of large-scale quantum many-body systems and the realization of universal quantum computation without time-dependent control. We experimentally demonstrate quantum walks of one and two strongly correlated microwave photons in a one-dimensional array of 12 superconducting qubits with short-range interactions. First, in one-photon quantum walks, we observed the propagation of the density and correlation of the quasiparticle excitation of the superconducting qubit and quantum entanglement between qubit pairs. Second, when implementing two-photon quantum walks by exciting two superconducting qubits, we observed the fermionization of strongly interacting photons from the measured time-dependent long-range anticorrelations, representing the antibunching of photons with attractive interactions. The demonstration of quantum walks on a quantum processor, using superconducting qubits as artificial atoms and tomographic readout, paves the way to quantum simulation of many-body phenomena and universal quantum computation.

Understanding various phenomena in non-equilibrium dynamics of closed quantum many-body systems, such as quantum thermalization, information scrambling, and nonergodic dynamics, is a crucial for modern physics. Using a ladder-type superconducting quantum processor, we perform analog quantum simulations of both the $XX$ ladder and one-dimensional (1D) $XX$ model. By measuring the dynamics of local observables, entanglement entropy and tripartite mutual information, we signal quantum thermalization and information scrambling in the $XX$ ladder. In contrast, we show that the $XX$ chain, as free fermions on a 1D lattice, fails to thermalize, and local information does not scramble in the integrable channel. Our experiments reveal ergodicity and scrambling in the controllable qubit ladder, and opens the door to further investigations on the thermodynamics and chaos in quantum many-body systems., Comment: 5 pages, 4 figures, and supplementary materials with 10 pages, 3 tables and 14 figures

We report the analog simulation of an ergodic-localized junction by using an array of 12 coupled superconducting qubits. To perform the simulation, we fabricated a superconducting quantum processor that is divided into two domains: one is a driven domain representing an ergodic system, while the second is localized under the effect of disorder. Because of the overlap between localized and delocalized states, for a small disorder there is a proximity effect and localization is destroyed. To experimentally investigate this, we prepare a microwave excitation in the driven domain and explore how deep it can penetrate the disordered region by probing its dynamics. Furthermore, we perform an ensemble average over 50 realizations of disorder, which clearly shows the proximity effect. Our work opens a new avenue to build quantum simulators of driven-disordered systems with applications in condensed matter physics and material science.

Topological quantum computation based on anyons is a promising approach to achieve fault-tolerant quantum computing. The Majorana zero modes in the Kitaev chain are an example of non-Abelian anyons where braiding operations can be used to perform quantum gates. Here we perform a quantum simulation of topological quantum computing, by teleporting a qubit encoded in the Majorana zero modes of a Kitaev chain. The quantum simulation is performed by mapping the Kitaev chain to its equivalent spin version, and realizing the ground states in a superconducting quantum processor. The teleportation transfers the quantum state encoded in the spin-mapped version of the Majorana zero mode states between two Kitaev chains. The teleportation circuit is realized using only braiding operations, and can be achieved despite being restricted to Clifford gates for the Ising anyons. The Majorana encoding is a quantum error detecting code for phase flip errors, which is used to improve the average fidelity of the teleportation for six distinct states from $70.76 \pm 0.35 \% $ to $84.60 \pm 0.11 \%$, well beyond the classical bound in either case., comments are welcome

The development of high-fidelity two-qubit quantum gates is essential for digital quantum computing. Here, we propose and realize an all-microwave parametric controlled-Z (CZ) gates by coupling strength modulation in a superconducting Transmon qubit system with tunable couplers. After optimizing the design of the tunable coupler together with the control pulse numerically, we experimentally realized a 100 ns CZ gate with high fidelity of 99.38% ± 0.34% and the control error being 0.1%. We note that our CZ gates are not affected by pulse distortion and do not need pulse correction, providing a solution for the real-time pulse generation in a dynamic quantum feedback circuit. With the expectation of utilizing our all-microwave control scheme to reduce the number of control lines through frequency multiplexing in the future, our scheme draws a blueprint for the high-integrable quantum hardware design.

High-fidelity two-qubit gates are essential for the realization of large-scale quantum computation and simulation. Tunable coupler design is used to reduce the problem of parasitic coupling and frequency crowding in many-qubit systems and thus thought to be advantageous. Here we design an extensible 5-qubit system in which center transmon qubit can couple to every four near-neighboring qubits via a capacitive tunable coupler and experimentally demonstrate high-fidelity controlled-phase (CZ) gate by manipulating central qubit and one near-neighboring qubit. Speckle purity benchmarking and cross entropy benchmarking are used to assess the purity fidelity and the fidelity of the CZ gate. The average purity fidelity of the CZ gate is 99.69±0.04% and the average fidelity of the CZ gate is 99.65±0.04%, which means that the control error is about 0.04%. Our work is helpful for resolving many challenges in implementation of large-scale quantum systems.

Quantum resetting protocols allow a quantum system to be sent to a state in the past by making it interact with quantum probes when neither the free evolution of the system nor the interaction is controlled. We experimentally verify the simplest non-trivial case of a quantum resetting protocol, known as the $\mathcal{W}_4$ protocol, with five superconducting qubits, testing it with different types of free evolutions and target-probe interactions. After projection, we obtained a reset state fidelity as high as $0.951$, and the process fidelity was found to be $0.792$. We also implemented 100 randomly-chosen interactions and demonstrated an average success probability of $0.323$ for $|1\rangle$ and $0.292$ for $|-\rangle$, experimentally confirmed the nonzero probability of success for unknown interactions; the numerical simulated values are about $0.3$. Our experiment shows that the simplest quantum resetting protocol can be implemented with current technologies, making such protocols a valuable tool in the eternal fight against unwanted evolution in quantum systems., 9 pages, 6 figures, 1 table + Supplementary Materials

Laser modulation is a process to modulate the photons to different states in quantum key distribution (QKD) system. A laser modulation driver, which is a pre-driver for the laser modulator, is presented in this paper. The laser modulation driver is implemented in a 130-nm complementary metal oxide semiconductor (CMOS) process. The laser modulation driver can provide a current pulse signal with an adjustable amplitude and an adjustable pulse-width to a distributed power amplifier. The pulse-width of the current signal can be adjusted from 300 ps to 3800 ps, the maximum adjustable amplitude is 14.4 mA, and the data rate can reach 625 Mb/s. According to the test results, the laser modulation driver can meet the requirements of the electro-optic modulator (EOM) in QKD system, and it can be used in the laser modulation circuit in QKD experiments.

Adiabatic quantum computing enables the preparation of many-body ground states. This is key for applications in chemistry, materials science, and beyond. Realisation poses major experimental challenges: Direct analog implementation requires complex Hamiltonian engineering, while the digitised version needs deep quantum gate circuits. To bypass these obstacles, we suggest an adiabatic variational hybrid algorithm, which employs short quantum circuits and provides a systematic quantum adiabatic optimisation of the circuit parameters. The quantum adiabatic theorem promises not only the ground state but also that the excited eigenstates can be found. We report the first experimental demonstration that many-body eigenstates can be efficiently prepared by an adiabatic variational algorithm assisted with a multi-qubit superconducting coprocessor. We track the real-time evolution of the ground and exited states of transverse-field Ising spins with a fidelity up that can reach about 99%., Comment: 12 pages, 4 figures

We present a laser source driver using a 130-nm complementary metal oxide semiconductor technology, named quantum laser source driver 2018 (QLSD2018). QLSD2018 drives the optical source with a current pulse signal, and the output of QLSD2018 has an adjustable pulse-width from 300 ps to 3.8 ns and an adjustable amplitude up to 70 mA. The data rate is up to 625 Mb/s, and the extinction ratio of the optical source (the 1550-nm distributed feedback laser or the 850-nm vertical-cavity surface-emitting laser) driven by QLSD2018 can reach 26 dB. The test results indicate that QLSD2018 can be used in quantum key distribution experiments. Using QLSD2018 on the transmitter side can significantly simplify the peripheral circuit of the optical source.

Superconducting circuits have emerged as a powerful platform of quantum simulation, especially for emulating the dynamics of quantum many-body systems, because of their tunable interaction, long coherence time, and high-precision control. Here in experiments, we construct a Bose-Hubbard ladder with a ladder array of 20 qubits on a 24-qubit superconducting processor. We investigate theoretically and demonstrate experimentally the dynamics of single- and double-excitation states with distinct behaviors, indicating the uniqueness of the Bose-Hubbard ladder. We observe the linear propagation of photons in the single-excitation case, satisfying the Lieb-Robinson bounds. The double-excitation state, initially placed at the edge, localizes; while placed in the bulk, it splits into two single-excitation modes spreading linearly toward two boundaries, respectively. Remarkably, these phenomena, studied both theoretically and numerically as unique properties of the Bose-Hubbard ladder, are represented coherently by pairs of controllable qubits in experiments. Our results show that collective excitations, as a single mode, are not free. This work paves the way to simulation of exotic logic particles by subtly encoding physical qubits and exploration of rich physics by superconducting circuits.

Quantum Key Distribution (QKD) is the most mature method for implementing commercial quantum communications in practice. As part of the miniaturization of practical QKD devices, an integrated electronic system in the 130 nm complementary metal oxide semiconductor process is presented for the QKD sender device. The electronics provide driving signals for the optics at the sender terminal of the quantum channel in QKD and consist mainly of three key modules, namely, a laser diode driver with a high slew rate, a high-speed physical random number generator, and a pre-driver for the electro-optic modulator. The electronic system is designed to operate at frequencies as high as 625-MHz to accommodate the frequency of the QKD system. The high degree of integration is advantageous for miniaturizing QKD sender devices.

We report the preparation and verification of a genuine 12-qubit entanglement in a superconducting processor. The processor that we designed and fabricated has qubits lying on a 1D chain with relaxation times ranging from 29.6 to 54.6 μs. The fidelity of the 12-qubit entanglement was measured to be above 0.5544±0.0025, exceeding the genuine multipartite entanglement threshold by 21 statistical standard deviations. After thermal cycling, the 12-qubit state fidelity was further improved to be above 0.707±0.008. Our entangling circuit to generate linear cluster states is depth invariant in the number of qubits and uses single- and double-qubit gates instead of collective interactions. Our results are a substantial step towards large-scale random circuit sampling and scalable measurement-based quantum computing.

Superconducting quantum computers (SQC) can solve some specific problems which are deeply believed to be intractable for classical computers. The control and measurement of qubits can't go on without the synchronous operation of digital-to-analog converters (DAC) array and the controlled sampling of analog-to-digital converters (ADC). In this paper, a scalable self-adaptive synchronous triggering system is proposed to ensure the synchronized operation of multiple qubits. The skew of the control signal between different qubits is less than 25 ps. After upgrading the clock design, the 250 MHz single-tone phase noise of DAC has been increased about 15 dB. The phase noise of the 6.25 GHz qubit control signal has an improvement of about 6 dB., 5 pages, 12 figures, IEEE Real Time Conference

The prompt gamma neutron activation analysis (PGNAA) technique is a real-time online method to analyze the composition of industrial materials. This paper presents a data acquisition system with a high count rate and real-time digital processing method for PGNAA. Limited by the decay time of the detector, the ORTEC multi-channel analyzer (MCA) can normally achieve an average count rate of 100 kcps. However, this system uses an electrical technique to increase the average count rate and reduce dead time, and guarantees good accuracy. Since the measuring time is usually limited to about 120 s, in order to accelerate the accumulation rate of spectrum and reduce the statistical error, the average count rate is expected to reach more than 500 kcps.

Superconducting quantum processors are manufactured based on a semiconductor process, which makes qubit integration possible. At the same time, this kind of qubit exhibits high-performance fidelity and decoherence time and requires a programmable arbitrary waveform generator (AWG). This paper presents the implementation of an AWG with a sampling rate of two-gigabit samples per second as well as 16-bit vertical resolution digital-to-analog converters. The AWGs are designed for a scaled-up usage scenario by integrating them with separate microwave devices onto a single backplane. A special waveform sequence output controller is designed to realize seamless waveform switching and arbitrary waveform generation. The jitter of multiple AWG channels is around 10 ps, and the integral nonlinearity and differential nonlinearity are both about 2 least significant bits. This customizable AWG has been used in several superconducting quantum processors, and the result of multiple qubits’ measurement verifies that the AWG is qualified for controlling tens of superconducting qubits.Superconducting quantum processors are manufactured based on a semiconductor process, which makes qubit integration possible. At the same time, this kind of qubit exhibits high-performance fidelity and decoherence time and requires a programmable arbitrary waveform generator (AWG). This paper presents the implementation of an AWG with a sampling rate of two-gigabit samples per second as well as 16-bit vertical resolution digital-to-analog converters. The AWGs are designed for a scaled-up usage scenario by integrating them with separate microwave devices onto a single backplane. A special waveform sequence output controller is designed to realize seamless waveform switching and arbitrary waveform generation. The jitter of multiple AWG channels is around 10 ps, and the integral nonlinearity and differential nonlinearity are both about 2 least significant bits. This customizable AWG has been used in several superconducting quantum processors, and the result of multiple qubits’ measurement verifies that the A...

In order to measure the neutron flux of 14 MeV, we designed a real-time data acquisition system which can supply power for 20 neutron detectors (crystal ST-401 and PMT) and collect neutron signals and count. The system can eliminate the interference of X and γ signals by using anti saturation front end circuit and pile up rejection, etc. The instrument operation panel, built by virtual instrument technology, can monitor the status of instrument in real time and analyze the measurement results. The results show that the typical value of the neutron rate is 10 Mc/s, the stability of the high voltage is less than ±2.5 V, and the timing error is less than 1ns, the system achieves the design goal of the 10 Mc/s average count rate, anti-saturation, and stable high voltage output of 20 channel.

The prompt γ-ray neutron activation analysis (referred PGNAA) technology is a use of the strong penetrating power of neutron and γ-ray, which can get the whole information of the elements inside a thick material. Therefore, the PGNAA technology has become the best choice to meet the needs of detecting the composition of industrial materials. This paper presents a data acquisition scheme for the physical targets of PGNAA, which has a high pass rate, high SNR and can analyze and process a large number of pulses which the detector outputs. This system is designed to rapidly analyze the composition and content of the industrial materials in real-time. Since we have to dynamically analyze the moving materials, the expected time for a measurement can not exceed 120s, The average counting rate is expected to reach more than 500kc/s.

Random number generators are wildly used in many applications in a diverse set of areas ranging from statistics to cryptography. Pseudo random number generators (PRNGs) are quite satisfactory for most applications. However, for cryptography and security applications, true random number generators (TRNGs) are required for the unpredictability. High density and high data output rate are as important as the quality of the TRNG in the nowadays true random number required devices and instruments. We present the design and the primary test results of our 10-Gbps TRNG, which is named TRNG2015, in the paper. The entropy source of the TRNG2015 is the jitter of ring oscillators. The TRNG2015 is fabricated in a 130nm CMOS process and assembled in a 6mm × 6 mm QFN48 package. It has one LVDS clock input and ten LVDS random data outputs. The output data rate depends on the input clock which is up to 1 GHz, and the output data rate is up to 1 Gbps per channel and up to 10 Gbps in total.

We design a Data Acquisition (DAQ) system for a 10-Gbps true random number generator to verify the quality of the random number. The prototype of the DAQ is based on a Xilinx Vertex-6 FPGA evaluation board. The DAQ system has three parts: acquisition, cache, and data up-link. Acquisition is the interface to the high-speed random data, and we use Gigabit Transceiver (GTX) in FPGA to deserialize the random data. The 1Gbps high speed serial random data in each channel is deserialized into 62.5Mbps with 16bit width parallel data. The low speed parallel data can be handled by the FPGA code and cache the data in an external DDR3 memory. When enough random data is stored, the random data is upload to PC via Gigabit Ethernet for the finial verification. The BERT test shows that the total data error rate of the data link in the prototype is less than 6.25×10−1° with 1Gbps input. The prototype can cache up to 16Gbits random data with 1Gbps serial input, and it meets the requirements of the data acquisition for one channel of the random number generator and proves the DAQ structure.

Bit error rate (BER) is the principle measure of performance of a data transmission link. With the integration of high-speed transceivers inside a field programmable gate array (FPGA), the BER testing can now be handled by transceiver-enabled FPGA hardware. This provides a cheaper alternative to dedicated table-top equipment and offers the flexibility of test customization and data analysis. This paper presents a BER tester implementation based on the Altera Stratix II GX and IV GT development boards. The architecture of the tester is described. Lab test results and field test data analysis are discussed. The Stratix II GX tester operates at up to 5 Gbps and the Stratix IV GT tester operates at up to 10 Gbps, both in 4 duplex channels. The tester deploys a pseudo random bit sequence (PRBS) generator and detector, a transceiver controller, and an error logger. It also includes a computer interface for data acquisition and user configuration. The tester's functionality was validated and its performance characterized in a point-to-point serial optical link setup. BER vs. optical receiver sensitivity was measured to emulate stressed link conditions. The Stratix II GX tester was also used in a proton test on a custom designed serializer chip to record and analyse radiation-induced errors.

The Thin Gap Chamber (TGC) is an important part of ATLAS detector and LHC accelerator. Targeting the feature of the output signal of TGC detector, we have designed a simulation signal source. The core of the design is based on field programmable gate array, randomly outputting 256-channel simulation signals. The signal is generated by true random number generator. The source of randomness originates from the timing jitter in ring oscillators. The experimental results show that the random number is uniform in histogram, and the whole system has high reliability.

A high voltage pulse generator is presented to drive Pockels cell. The Pockels cell behaves like a capacitor which slows the rise/fall time of the pulse and restrains the repetition rate of the generator. To drive the Pockels cell applied in quantum communication system, it requires about 1 MHz repetition rate with the rise/fall time of the pulse less than 50 ns, adjustable amplitude up to 800 V and an adjustable duration. With the assistance of self-designed transformers, the circuits is simplified that a pair of high current radio frequency (RF) MOSFET drivers are employed to switch the power MOSFETs at a high speed, and the power MOSFETs shape the final output pulse with the requirements. From the tests, the generator can produce 800 V square pulses continously at 1 MHz rate with 46 ns in risetime and 31 ns in falltime when driving a 51 pF capacitive load. And the generator is now used to drive Pockels cell for encoding the polarization of photons.

A random number generator with high data rate, small size, and low power consumption is essential for a certain quantum key distribution (QKD) system. We designed a 10 Gbps random number generator ASIC, TRNG2016, for the QKD system. With a 6 mm × 6 mm QFN48 package, TRNG2016 has 10 independent physical random number generation channels, and each channel can work at a fixed frequency up to 1 Gbps. The random number generated by TRNG2016 can pass the NIST statistical tests without any post-processing. With 3.3 V IO power supply and 1.2 V core power supply, the typical power consumption of TRNG2016 is 773 mW with 10 channels on and running at 1 Gbps data rate.

We introduce a data acquisition (DAQ) system for frequency-locking in Direct Detection Doppler Wind LIDAR (DWL). In DWL, double-edge technique based on Fabry-Perot etalon is used to detect the frequency shift. Tiny frequency shift could distinctly reflected in amplitude of output pulse from Photomultiplier Tube (PMT). Nevertheless, outgoing laser frequency is sensitive to temperature changes. Moreover, vibration would intensify the influence especially on vehicle-mounted DWL. The locking channel is designed for stabling the outgoing laser frequency. An approach of detecting the self-frequency shift in commercial DWL is to measure amplitude variation by PMT. Our DAQ system is designed for pulse signals sampling and processing. The system includes a DAQ hardware system and a dedicated DAQ software. The raw data sampled by hardware would transferred to DAQ software at PC via universal serial bus (USB). We use appropriative algorithm in data processing for relatively low sampling rate. Our system reports the same results as commercial oscilloscope and the tests show that the DAQ system meets the locking requirements.

We present a low-latency, small-form-factor optical link designed for the high-luminosity LHC experiments in which the latency and form factor are critical. The optical link on the transmitter side is composed of a transmitter ASIC and a custom-made optical transmitter module. The transmitter ASIC includes an encoder and a serializer. Two serializer ASIC prototypes, operating at 5 and 8 Gbps per channel respectively, have been designed and tested. A low-latency, low-overhead encoder has been verified in FPGAs and is being integrated into a two-channel, 8∶1 transmitter ASIC with each channel operating at 5.12 Gbps. A prototype of the custom-made optical transmitter module (called MTx) with separate transmitter optical sub-assemblies (TOSAs) has been demonstrated. A Vertical-Cavity Surface-Emitting Laser (VCSEL) driver ASIC has been developed and will replace the commercial VCSEL laser driver used in the current MTx prototypes. The latency of the whole link, including the transmitter latency and the receiver latency but not including the latency of the fiber, is estimated to be less than 80 ns. The size of the MTx is 42 mm × 15 mm × 6 mm.

An all transistor active inductor shunt peaking structure has been used in a prototype of 8-Gbps high-speed VCSEL driver which is designed for the optical link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated in a commercial 0.25-um Silicon-on-Sapphire (SoS) CMOS process for radiation tolerant purpose. The all transistor active inductor shunt peaking is used to overcome the bandwidth limitation from the CMOS process. The peaking structure has the same peaking effect as the passive one, but takes a small area, does not need linear resistors and can overcome the process variation by adjust the peaking strength via an external control. The design has been tapped out, and the prototype has been proofed by the preliminary electrical test results and bit error ratio test results. The driver achieves 8-Gbps data rate as simulated with the peaking. We present the all transistor active inductor shunt peaking structure, simulation and test results in this paper., 4 pages, 6 figures and 1 table, Submitted to 'Chinese Physics C'

A low noise Front End Electronics (FEE) for two-dimensional position sensitive Micro-Channel Plate (MCP) detector has been developed. The MCP detector is based on Wedge and Strip Anode (WSA) with induction readout mode. The WSA has three electrodes, the wedge electrode, the strip electrode, and the zigzag electrode. Then, three readout channels are designed in the Printed Circuit Board (PCB). The FEE is calibrated by a pulse generator from Agilent. We also give an analysis of the charge loss from the CSA. The noise levels of the three channels are less than 1 fC RMS at the shaping time of 200 ns. The experimental result shows that the position resolution of the MCP detector coupled with the designed PCB can reach up to 110 μm.

Quantum random number generators adopting single photon detection have been restricted due to the non-negligible dead time of avalanche photodiodes (APDs). We propose a new approach based on an APD array to improve the generation rate of random numbers significantly. This method compares the detectors' responses to consecutive optical pulses and generates the random sequence. We implement a demonstration experiment to show its simplicity, compactness and scalability. The generated numbers are proved to be unbiased, post-processing free, ready to use, and their randomness is verified by using the national institute of standard technology statistical test suite. The random bit generation efficiency is as high as 32.8% and the potential generation rate adopting the 32 × 32 APD array is up to tens of Gbits/s.

In this paper, we present a multi-channel high precision pulse synchronizer. The synchronizer supplies pulses of three different requirements. It's mainly constituted of high precision clock fan-out circuit and wideband Bipolar Junction Transistor (BJT) circuit. In order to obtain large voltage amplitude as well as high current, we use over voltage driving technology in the BJT circuits. The results of the electronic tests show that the output pulses meet the requirements of the high precision instruments in physics experiments.

In many detection systems, the front-end electronics will receive the signals from detectors and handle them, but many detectors could give very large signals which will cause circuit saturation and waveform oscillation, this will lead to abnormal results of the whole electronics system. In this paper, according to a typical structure of front-end electronics, a kind of non-linear anti-saturation improvement method and circuit is introduced. And the simulation and experimental research show that the improvement solution is successful.

A novel FPGA-based pulse pile-up rejection method for single photon imaging detectors is reported. The method is easy to implement in FPGAs for real-time data processing. The rejection principle and entire design are introduced in detail. The photon counting imaging detector comprises a micro-channel plate (MCP) stack, and a wedge and strip anode (WSA). The resolution mask pattern in front of the MCP can be reconstructed after data processing in the FPGA. For high count rates, the rejection design can effectively reduce the impact of the pulse pile-up on the image. The resolution can reach up to 140 μm. The pulse pile-up rejection design can also be applied to high-energy physics and particle detection.