Heming Wang

Stanford University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Kerry J. Vahala

California Institute of Technology

Boqiang Shen

SA Photonics (United States)

John E. Bowers

University of California, Santa Barbara

Lue Wu

California Institute of Technology

Qi‐Fan Yang

Peking University

Zhiquan Yuan

California Institute of Technology

Qing-Xin Ji

California Institute of Technology

Lin Chang

Peking University

Warren Jin

University of California, Santa Barbara

Mario Paniccia

Photonics (United States)

Cooperative Institutions

Peking University

University of California, Santa Barbara

Chinese Academy of Sciences

California Institute of Technology

Tsinghua University

Air Force Engineering University

University of Science and Technology of China

Shanghai Jiao Tong University

Stanford University

Zhejiang University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

A self-starting bi-chromatic LiNbO3 soliton microcomb

arXiv (Cornell University) (2018)

Yang He Qi‐Fan Yang Jingwei Ling Rui Luo Hanxiao Liang

For its many useful properties, including second and third-order optical nonlinearity as well as electro-optic control, lithium niobate is considered an important potential microcomb material. Here, a soliton microcomb is demonstrated in a monolithic high-Q lithium niobate resonator. Besides the demonstration of soliton mode locking, the photorefractive effect enables mode locking to self-start and soliton switching to occur bi-directionally. Second-harmonic generation of the soliton spectrum is also observed, an essential step for comb self-referencing. The Raman shock time constant of lithium niobate is also determined by measurement of soliton self-frequency-shift. Besides the considerable technical simplification provided by a self-starting soliton system, these demonstrations, together with the electro-optic and piezoelectric properties of lithium niobate, open the door to a multi-functional microcomb providing f-2f generation and fast electrical control of optical frequency and repetition rate, all of which are critical in applications including time keeping, frequency synthesis/division, spectroscopy and signal generation.

10.48550/arxiv.1812.09610

Cite

Citations (50)

Large‐Scale Worst‐Case Topology Optimization

Computer Graphics Forum (2022)

Di Zhang Xiaoya Zhai Xiao‐Ming Fu Heming Wang Ligang Liu

Abstract We propose a novel topology optimization method to efficiently minimize the maximum compliance for a high‐resolution model bearing uncertain external loads. Central to this approach is a modified power method that can quickly compute the maximum eigenvalue to evaluate the worst‐case compliance, enabling our method to be suitable for large‐scale topology optimization. After obtaining the worst‐case compliance, we use the adjoint variable method to perform the sensitivity analysis for updating the density variables. By iteratively computing the worst‐case compliance, performing the sensitivity analysis, and updating the density variables, our algorithm achieves the optimized models with high efficiency. The capability and feasibility of our approach are demonstrated over various large‐scale models. Typically, for a model of size 512×170×170 and 69934 loading nodes, our method took about 50 minutes on a desktop computer with an NVIDIA GTX 1080Ti graphics card with 11 GB memory.

Topology optimization

10.1111/cgf.14698

Cite

Citations (3)

On the CR Nirenberg problem: density and multiplicity of solutions

arXiv (Cornell University) (2024)

Zhongwei Tang Heming Wang B.G Zhang

We prove some results on the density and multiplicity of positive solutions to the prescribed Webster scalar curvature problem on the $(2n+1)$-dimensional standard unit CR sphere $(\mathbb{S} ^{2n+1},\theta_0)$. Specifically, we construct arbitrarily many multi-bump solutions via the variational gluing method. In particular, we show the Webster scalar curvature functions of contact forms conformal to $\theta_0$ are $C^{0}$-dense among bounded functions which are positive somewhere. Existence results of infinitely many positive solutions to the related equation $-\Delta_{\mathbb{H}} u=R(\xi) u^{(n+2) /n}$ on the Heisenberg group $\Hn $ with $R(\xi)$ being asymptotically periodic with respect to left translation are also obtained. Our proofs make use of a refined analysis of bubbling behavior, gradient flow, Pohozaev identity, as well as blow up arguments.

Multiplicity (mathematics)

10.48550/arxiv.2404.13622

Cite

Citations (0)

Sub-kHz linewidth integrated Pockels laser

Shixin Xue Mingxiao Li Jingwei Ling Zhengdong Gao Qili Hu

We demonstrate a sub-kHz linewidth integrated Pockels laser with a mode-hop-free linear frequency modulation range of 15 GHz, and an on-chip power of 5.4 mW.

Laser linewidth

Pockels effect

10.1364/cleo_si.2024.sth3m.4

Cite

Citations (0)

Fractal analysis and its impact factors on pore structure of artificial cores based on the images obtained using magnetic resonance imaging

Journal of Applied Geophysics (2012)

Heming Wang Yu Liu Yongchen Song Yuechao Zhao Jiafei Zhao

Box counting

10.1016/j.jappgeo.2012.07.015

Cite

Citations (134)

Universal isocontours for dissipative Kerr solitons

Optics Letters (2018)

Xinbai Li Boqiang Shen Heming Wang Ki Youl Yang Xu Yi

Dissipative Kerr solitons can be generated within an existence region defined on a space of normalized pumping power versus cavity-pump detuning frequency.The contours of constant soliton power and constant pulse width in this region are studied through measurement and simulation.Such isocontours impart structure to the existence region and improve understanding of soliton locking and stabilization methods.As part of the study, dimensionless, closed-form expressions for soliton power and pulse width are developed (including Raman contributions).They provide isocontours in close agreement with those from the full simulation, and, as universal expressions, can simplify the estimation of soliton properties across a wide range of systems.

Dissipative soliton

Dimensionless quantity

Constant (computer programming)

10.1364/ol.43.002567

Cite

Citations (7)

A 33.33 Gb/s/wire pin-efficient 1.06 pJ/bit wireline transceiver based on CNRZ-5 for Chiplet in 28 nm CMOS

Microelectronics Journal (2022)

Mingche Lai Geng Zhang Fangxu Lv Xuqiang Zheng Heming Wang

This paper presents a low-power, high-bandwidth wireline transceiver for chiplet. The transceiver uses a new technology of correlated non-return to zero (CNRZ) to improve the pin efficiency and reduce the noise of the common mode and crosstalk (CMN and XTALK). The transmitter adopts a 4:1 multiplexer (MUX) and a special voltage-mode driver [source series terminated (SST)] to improve the power efficiency. The receiver utilizes a low jitter clock-and-data alignment (CDA) based on high resolution phase interpolator (PI) and a MINI-PLL with differential filter based to improve the jitter performance of the receiver's clock. In addition, a special continuous-time linear equalizer (CTLE) is introduced into the multiple-input compare (MIC) based decode circuit to reduce the receiver's bit error rate (BER). This transceiver is designed with a 28 nm CMOS process technology and supplied with 0.9/1.2 V. Simulation results show that this transceiver can operate at 200 Gb/s with the 33.3 Gb/s single-wire data rate and a power consumption of 1.06 pJ/b. The transceiver's BER is less than 1E-15 and eye-wide-opening is 12.02 ps (48.08% UI), which is under 10 dB channel loss at 20 GHz Nyquist frequency.

Transceiver

SerDes

Wireline

Electrical efficiency

10.1016/j.mejo.2022.105628

Cite

Citations (3)

Turnkey locking of quantum-dot lasers directly grown on Si

arXiv (Cornell University) (2024)

Bozhang Dong Yating Wan Weng W. Chow Chen Shang A. F. Prokoshin

Ultra-low-noise laser sources are crucial for a variety of applications, including microwave synthesizers, optical gyroscopes, and the manipulation of quantum systems. Silicon photonics has emerged as a promising solution for high-coherence applications due to its ability to reduce system size, weight, power consumption, and cost (SWaP-C). Semiconductor lasers based on self-injection locking (SIL) have reached fiber laser coherence, but typically require a high-Q external cavity to suppress coherence collapse through frequency-selective feedback. Lasers based on external-cavity locking (ECL) are a low-cost and turnkey operation option, but their coherence is generally inferior to SIL lasers. In this work, we demonstrate quantum-dot (QD) lasers grown directly on Si that achieve SIL laser coherence under turnkey ECL. The high-performance QD laser offers a scalable and low-cost heteroepitaxial integration platform. Moreover, the QD laser's chaos-free nature enables a 16 Hz Lorentzian linewidth under ECL using a low-Q external cavity, and improves the frequency noise by an additional order of magnitude compared to conventional quantum-well lasers.

Laser linewidth

Relative intensity noise

10.48550/arxiv.2401.01560

Cite

Citations (0)

Microresonator Spectrometer Using Counter-propagating Solitons

Conference on Lasers and Electro-Optics (2019)

Qi‐Fan Yang Boqiang Shen Heming Wang Minh A. Tran Zhewei Zhang

A spectrometer is demonstrated using self-locked counter-propagating soliton frequency combs in a high-Q silica microresonator. Fast tuning laser waveforms and molecular absorption features are measured with kiloHertz to MegaHertz resolution.

10.1364/cleo_at.2019.af2k.1

Cite

Citations (0)

Integrated turnkey soliton microcombs: Data and Code

Zenodo (CERN European Organization for Nuclear Research) (2020)

Boqiang Shen Lin Chang Junqiu Liu Heming Wang Qi‐Fan Yang

Data.zip contains raw datasets generated in the experiment and analysed during the study. Code.zip contains the MATLAB code for processing the data and generating figures in the paper and its supplementary information, as well as the Mathematica code to model the turnkey soliton generation. Please put the MATLAB script in the same directory as the Data folder and add the folder Code/Lib to MATLAB path.

Turnkey

Code (set theory)

10.5281/zenodo.3700189

Cite

Citations (0)