SQuaD: Smart Quantum Detection for Photon Recognition and Dark Count Elimination

TL;DR

SQuaD tackles the limitation of conventional photon detectors by enabling multi-dimensional photon characterization while suppressing dark counts. The approach fuses an SNSPD-based detector, an RFSoC FPGA, and an embedded fully connected neural network to perform real-time feature extraction and feedback. Key results include up to $100\%$ accuracy in wavelength and polarization recognition, effective dark-count elimination, and a $>90\%$ detection efficiency benchmark, demonstrated on a telecom-band erbium emitter. This work enables noise-free readout and higher fidelity in quantum networks and distributed quantum information processing.

Abstract

Quantum detectors of single photons are an essential component for quantum information processing across computing, communication and networking. Today's quantum detection system, which consists of single photon detectors, timing electronics, control and data processing software, is primarily used for counting the number of single photon detection events. However, it is largely incapable of extracting other rich physical characteristics of the detected photons, such as their wavelengths, polarization states, photon numbers, or temporal waveforms. This work, for the first time, demonstrates a smart quantum detection system, SQuaD, which integrates a field programmable gate array (FPGA) with a neural network model, and is designed to recognize the features of photons and to eliminate detector dark-count. The SQuaD is a fully integrated quantum system with high timing-resolution data acquisition, onboard multi-scale data analysis, intelligent feature recognition and extraction, and feedback-driven system control. Our \name experimentally demonstrates 1) reliable photon counting on par with the state-of-the art commercial systems; 2) high-throughput data processing for each individual detection events; 3) efficient dark count recognition and elimination; 4) up to 100\% accurate feature recognition of photon wavelength and polarization. Additionally, we deploy the SQuaD to an atomic (erbium ion) photon emitter source to realize noise-free control and readout of a spin qubit in the telecom band, enabling critical advances in quantum networks and distributed quantum information processing.

Figures (18)

• Figure 1: An overview of the proposed SQuaD system, FPGA is the central processor for data acquisition from SNSPD, data analysis with neural network model, different feature extraction of photons and whole system control.
• Figure 2: Comparison between the current single photon quantum detection system with our proposed smart quantum detection system-SQuaD.
• Figure 3: Block diagram of SQuaD showing three modules: initial, process, and feedback module, respectively.
• Figure 4: ZCU 111 evaluation board for SQuaD system. Hardware specification includes: Zynq RFSoc processing system with CPU + FPGA, RF ADC with 4 GSPS, RF DAC with 6.5 GSPS, and Ethernet ports for data communication and system control
• Figure 5: WSi-Based Superconducting Nanowire Single-Photon Detector, the experimental dilute fridge with customized SNSPD depicted in (a) and (b), (c) the electronic circuit for the operation of SNSPD.