arXiv subjects

Mengyue Xu

Publications and source records attributed to Mengyue Xu.

7 recordsLinked to original sources

arXiv2026

Push-Pull acousto-optic modulator based on non-suspended thin-film lithium niobate on silicon substrate

Acousto-optic modulators (AOMs) are particularly attractive for microwave-to-optical conversion, quantum transduction, and optical frequency manipulation. For these applications, chip-scale AOMs that combine high efficiency, broad bandwidth, and low optical loss are highly desirable. Although suspended and resonant AOMs can enhance modulation efficiency, they typically suffer from stability concerns and limited bandwidth. Here, we demonstrate a non-suspended built-in push-pull AOM on a thin-film lithium niobate (TFLN) on silicon substrate that simultaneously offers high efficiency and relatively broad bandwidth. We further investigate the orientation dependence of electromechanical coupling in X-cut TFLN by fabricating devices with different acoustic propagation directions and identify an optimized orientation for enhanced acousto-optic transduction. Our low-loss device achieves a half-wave voltage-length product of 1.004 V cm at 0.842 GHz with an interaction length of 400 micrometers, together with a relatively wide acousto-optic modulation bandwidth of 132.5 MHz. These results pave the way for efficient, practical integrated photonic-phononic links.

physics.optics↗

arXiv2024

120 GOPS Photonic Tensor Core in Thin-film Lithium Niobate for Inference and in-situ Training

Photonics offers a transformative approach to artificial intelligence (AI) and neuromorphic computing by enabling low-latency, high-speed, and energy-efficient computations. However, conventional photonic tensor cores face significant challenges in constructing large-scale photonic neuromorphic networks. Here, we propose a fully integrated photonic tensor core, consisting of only two thin-film lithium niobate (TFLN) modulators, a III-V laser, and a charge-integration photoreceiver. Despite its simple architecture, it is capable of implementing an entire layer of a neural network with a computational speed of 120 GOPS, while also allowing flexible adjustment of the number of inputs (fan-in) and outputs (fan-out). Our tensor core supports rapid in-situ training with a weight update speed of 60 GHz. Furthermore, it successfully classifies (supervised learning) and clusters (unsupervised learning) 112 * 112-pixel images through in-situ training. To enable in-situ training for clustering AI tasks, we offer a solution for performing multiplications between two negative numbers.

physics.optics↗

arXiv2021

High Performance Polarization Management Devices Based on Thin-Film Lithium Niobate

High-speed polarization management is highly desirable for many applications, such as remote sensing, telecommunication, and medical diagnosis. However, most of the approaches for polarization management rely on bulky optical components that are slow to respond, cumbersome to use, and sometimes with high drive voltages. Here, we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform. We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities, including arbitrary polarization generation, fast polarization measurement, polarization scrambling, and automatic polarization control. The present devices feature ultra-fast control speed, low drive voltages, low optical losses and compact footprints. Using these devices, we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB, fast polarization scrambling with a scrambling rate up to 65 Mrad/s, and endless polarization control with a tracking speed up to 10 Krad/s, all of which are best results in integrated optics. The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices, leading to a paradigm shift in polarization management.

physics.optics↗

arXiv2020

High-performance Coherent Optical Modulators based on Thin-film Lithium Niobate Platform

The coherent transmission technology using digital signal processing and advanced modulation formats, is bringing networks closer to the theoretical capacity limit of optical fibres, the Shannon limit. The in-phase quadrature electro-optic modulator that encodes information on both the amplitude and the phase of light, is one of the underpinning devices for the coherent transmission technology. Ideally, such modulator should feature low loss, low drive voltage, large bandwidth, low chirp and compact footprint. However, these requirements have been only met on separate occasions. Here, we demonstrate integrated thin-film lithium niobate in-phase/quadrature modulators that fulfil these requirements simultaneously. The presented devices exhibit greatly improved overall performance (half-wave voltage, bandwidth and optical loss) over traditional lithium niobate counterparts, and support modulation data rate up to 320 Gbit s-1. Our devices pave new routes for future high-speed, energy-efficient, and cost-effective communication networks.

physics.app-ph↗

arXiv2019

A Polarization-insensitive and High-speed Electro-optic Switch Based on a Hybrid Silicon and Lithium Niobate Platform

We propose and demonstrate a polarization-insensitive and high speed optical switch unit based on a silicon and lithium niobate hybrid integration platform. The presented device exhibits a sub nano-second switching time, low drive voltages of 4.97 V, and low power dissipation due to electrostatic operation. The measured polarization dependence loss was lower than 0.8 dB. The demonstrated optical switch could provide as a building block for polarization-insensitive and high-speed optical matrix switches.

physics.app-ph↗

arXiv2019

Lithium Niobate Michelson Interferometer Modulator on Silicon-On-Insulator Platform

We propose and demonstrate a hybrid silicon and lithium niobate Michelson Interferometer Modulator (MIM) with enhanced modulation efficiency compared to a Mach-Zehnder modulator. The modulator is based on seamless integration of a high-contrast waveguide based on lithium niobate-a popular modulator material-with compact, low-loss silicon circuitry. The present device demonstrates a modulation efficiency as high as 1.2 Vcm and a low insertion loss of 3.3 dB. The 3dB electro-optic bandwidth is approximately 17.5 GHz. The optical eye diagrams, operating at 32 Gbit/s and 40 Gbit/s, with measured dynamic extinction ratios at 8 dB and 6.6 dB respectively. The present device avoids absorption loss and nonlinearity in conventional silicon modulators and demonstrates highest modulation efficiency in LN modulators, showing potential in future optical interconnects.

physics.app-ph↗

arXiv2018

High-Performance Hybrid Silicon and Lithium Niobate Mach-Zehnder Modulators for 100 Gbit/s and Beyond

Optical modulators are at the heart of optical communication links. Ideally, they should feature low insertion loss, low drive voltage, large modulation bandwidth, high linearity, compact footprint and low manufacturing cost. Unfortunately, these criteria have only been achieved on separate occasions.Based on a Silicon and Lithium Niobate hybrid integration platform, we demonstrate Mach-Zehnder modulators that simultaneously fulfill these criteria. The presented device exhibits an insertion loss of 2.5 dB, voltage-length product of 2.2 Vcm, high linearity, electro-optic bandwidth of at least 70 GHz and modulation rates up to 112 Gbit/s. The high-performance modulator is realized by seamless integration of high-contrast waveguide based on Lithium Niobate - the most mature modulator material - with compact, low-loss silicon circuits. The hybrid platform demonstrated here allows for the combination of 'best-in-breed' active and passive components, opening up new avenues for enabling future high-speed, energy efficient and cost-effective optical communication networks.

physics.app-ph↗