arXiv subjects

Guanhao Wu

Publications and source records attributed to Guanhao Wu.

6 recordsLinked to original sources

arXiv2026

Programmable electro-optic frequency comb empowers integrated parallel convolution processing

Integrated photonic convolution processors make optical neural networks (ONNs) a transformative solution for artificial intelligence applications such as machine vision. To enhance the parallelism, throughput, and energy efficiency of ONNs, wavelength multiplexing is widely applied. However, it often encounters the challenges of low compactness, limited scalability, and high weight reconstruction latency. Here, we proposed and demonstrated an integrated photonic processing unit with a parallel convolution computing speed of 1.62 trillion operations per second (TOPS) and a weight reconstruction speed exceeding 38 GHz. This processing unit simultaneously achieves, for the first time, multi-wavelength generation and weight mapping via a single programmable electro-optic (EO) frequency comb, featuring unprecedented compactness, device-footprint independent scalability, and near-unity optical power conversion efficiency (conversion efficiency from input optical power to output weighted comb lines). To demonstrate the reconfigurability and functionality of this processing unit, we implemented image edge detection and object classification based on EO combs obtained using the particle swarm algorithm and an EO comb neural network training framework, respectively. Our programmable EO comb-based processing framework establishes a new paradigm towards the development of low-latency monolithic photonic processors, promising real-time in-sensor learning for autonomous vehicles, intelligent robotics, and drones.

physics.optics↗

arXiv2025

Electro-optic frequency comb-empowered precise measurement of the dynamic frequency of a laser

Frequency-modulated lasers (FMLs) are widely used in spectroscopy, biology, and LiDAR. The performance of these applications highly depends on the fast and precise tracking of the FMLs' absolute frequency, which remains a challenge. Here we demonstrate integrated lithium niobate electro-optic frequency combs with arbitrarily tunable repetition rates and a 29.45-nm bandwidth, enabling precise tracking of the absolute frequency of an FML with a chirp rate as high as $2\times10^{18}\,\mathrm{Hz/s}$, which is over three orders of magnitude above the state of the art. This method enables frequency-modulated continuous-wave ranging using an FML with severe mode hops, unlocking great potential for improving the ranging resolution and acquisition rate. Our method lays the foundation for FML-based high-precision measurements of frequency, distance, and time, leading to profound implications in fundamental science and engineering applications.

physics.optics↗

arXiv2024

Precise and Fast LIDAR via Electrical Asynchronous Sampling Based on a Single Femtosecond Laser

Using a laser-based ranging method for precise environmental 3D sensing, LiDAR has numerous applications in science and industry. However, conventional LiDAR face challenges in simultaneously achieving high ranging precision and fast measurement rates, which limits their applicability in more precise fields, such as aerospace, smart healthcare and beyond. By employing an asynchronous electrical pulse sampling strategy on a single optical frequency comb with a stable repetition rate and femtosecond-pulse width, we exploit the advantages of optical-frequency-comb ranging method and overcome the limitations of sampling aliasing and low data-utilization inherent in traditional approaches. This enables a significant improvement of LiDAR's performance to achieve micrometer-level precision and megahertz-regimes update rates over meter-range on non-cooperative targets. Specifically, we achieve 38.8-$μ$m Allan deviation at 1-MHz update rate and 8.06-$μ$m Allan deviation after 2-ms time-averaging based on a 56.091-MHz femtosecond laser. This enhancement enables various advanced measurement applications, including metrology monitoring on high-speed objects, 1-megapixel/s precise 3D scanning imaging and first-ever contactless vital sign detection using time-of-flight LiDAR. This LiDAR unlock new possibilities for precise and fast real-time measurements in diverse fields.

physics.optics↗

arXiv2024

Electro-optic frequency combs carrying orbital angular momentum

To date, orbital angular momentum (OAM) and optical frequency combs (OFCs) are two distinct fields of research without any association. Herein, we generated OFCs with an OAM on each comb line by applying electro-optic phase modulation to the OAM beam. We verified that the OAM characteristic of the sidebands is consistent with that of the pump light. Our study bridges two distinct research fields OFCs and OAM opening the door to various fundamental research avenues and applications, including large-capacity optical communications, high-security optical encryption, multi-dimensional photon entanglement, and synthetic dimensions.

physics.optics↗

arXiv2023

Electro-optic frequency comb-enabled precise distance measurement with megahertz acquisition rate

Artificial intelligence empowered autonomous vehicles and robotics have to sense the fast-changing three-dimensional environment with high precision and speed. However, it is challenging for the state-of-the-art ambiguity-free light detection and ranging (LiDAR) techniques to achieve absolute distance measurement with simultaneous high precision and high acquisition rate. Here we demonstrate an electro-optic frequency comb-enabled precise absolute distance measurement method, repetition rate modulated frequency comb (RRMFC), with megahertz-level acquisition rate. To achieve RRMFC, we designed and fabricated an integrated lithium niobate phase modulator with a modulation length of 5 cm and a half-wave voltage of 1.52 V, leading to over 50 sidebands and a continuously tunable repetition rate. Leveraging these unique features, RRMFC can directly resolve distance in time domain, leading to an acquisition rate as high as 25 MHz and an Allan deviation down to 13.77 μm at an averaging time of 724 μs. Based on RRMFC, we achieved high-speed 3D imaging at millimeter-level precision with a single laser. RRMFC-based LiDAR allows the autonomous vehicles and robotics to sense the fine details of fast-changing environment with high precision.

physics.optics↗

arXiv2021

Fine Grained Human Evaluation for English-to-Chinese Machine Translation: A Case Study on Scientific Text

Recent research suggests that neural machine translation (MT) in the news domain has reached human-level performance, but for other professional domains, it is far below the level. In this paper, we conduct a fine-grained systematic human evaluation for four widely used Chinese-English NMT systems on scientific abstracts which are collected from published journals and books. Our human evaluation results show that all the systems return with more than 10\% error rates on average, which requires much post editing effort for real academic use. Furthermore, we categorize six main error types and and provide some real examples. Our findings emphasise the needs that research attention in the MT community should be shifted from short text generic translation to professional machine translation and build large scale bilingual corpus for these specific domains.

cs.CL↗