Publications by Xinru Ji | EPFL Graph Search

C- and L-band tunable integrated Erbium lasers via scalable manufacturing

Tobias Kippenberg, Grigorii Likhachev, Andrey Voloshin, Xinru Ji, Zheru Qiu

We demonstrate an integrated Erbium-based tunable laser using wafer-scale fabrication and ion implantation of silicon nitride photonic integrated circuits. We achieve single-frequency lasing tunable from 1530 nm to 1621 nm covering nearly the entire optica ...

Optica Publishing Group2025

High-Energy Mode-Locked Pulses from a Photonic Integrated Mamyshev Oscillator

Tobias Kippenberg, Grigorii Likhachev, Jianqi Hu, Xinru Ji, Zheru Qiu, Zihan Li

Mode-locked lasers (MLLs), capable of generating ultrashort coherent pulses, have been instrumental for numerous applications, including optical frequency metrology, eye surgery, machining, additive manufacturing, imaging and spectroscopy. However, commerc ...

IEEE2025

Silicon nitride waveguide or photonic integrated circuit fabrication method

Tobias Kippenberg, Xinru Ji

Silicon nitride waveguide fabrication method including providing a substrate including a stress release trench structure, the stress release recess structure being formed in a silicon oxide layer, depositing a silicon nitride material or layer onto the sil ...

2024

Sub-MHz linewidth, FMCW photonic integrated blue laser

Tobias Kippenberg, Xinru Ji, Anat Siddharth

We demonstrate for the first time a frequency-modulated continuous wave photonic integrated blue laser with sub-MHz linewidth. The laser exhibits frequency excursion greater than 900 MHz at up to 1 MHz triangular chirp rate with a nonlinearity of less than ...

Institute of Electrical and Electronics Engineers Inc.2024

Photonic substrate preparation method and photonic waveguide preparation or fabrication method

Tobias Kippenberg, Xinru Ji, Zheru Qiu

Photonic integrated circuit optical waveguide device preparation or fabrication method comprising providing a silicon substrate, depositing at least one copper gettering silicon nitride layer or material, depositing at least one optical waveguide cladding ...

2024

A fully hybrid integrated erbium-based laser

Rui Ning Wang, Tobias Kippenberg, Andrey Voloshin, Xinru Ji, Zheru Qiu, Andrea Bancora

Erbium-doped fibre lasers exhibit high coherence and low noise as required for fibre-optic sensing, gyroscopes, LiDAR and optical frequency metrology. Endowing erbium-based gain in photonic integrated circuits can provide a basis for miniaturizing low-nois ...

Nature Publishing Group2024

Lithium tantalate photonic integrated circuits for high volume manufacturing

Tobias Kippenberg, Mikhail Churaev, Xinru Ji, Zihan Li

We demonstrate the first photonic integrated circuit platform using Lithium Tantalate (LiTaO3), achieving waveguides with low losses (5.6 dB m−1), Mach-Zehnder modulators with a 40 GHz electro-optical bandwidth and a 1.96 V · cm voltage-length product, alo ...

Institute of Electrical and Electronics Engineers Inc.2024

Foundry compatible, efficient wafer-scale manufacturing of ultra-low loss, high-density Si3N4 photonic integrated circuits

Rui Ning Wang, Tobias Kippenberg, Xinru Ji, Zheru Qiu

We demonstrate ultra-low propagation loss, lithographic precision, and wafer-scale manufacturing for high-density Si3N4 photonic integrated circuits using an efficient DUV-based subtractive approach. We show a propagation loss as low as 1.4 dB/m at 1.55 µm ...

Optical Society of America2024

Photonic-electronic integrated circuit-based coherent LiDAR engine

Edoardo Charbon, Tobias Kippenberg, Grigorii Likhachev, Andrey Voloshin, Anton Lukashchuk, Halil Kerim Yildirim, Xinru Ji, Zheru Qiu, Andrea Bancora

Chip-scale integration is a key enabler for the deployment of photonic technologies. Coherent laser ranging or FMCW LiDAR, a perception technology that benefits from instantaneous velocity and distance detection, eye-safe operation, long-range, and immunit ...

Nature Portfolio2024

Efficient mass manufacturing of high-density, ultra-low-loss Si3N4 photonic integrated circuits

Rui Ning Wang, Tobias Kippenberg, Xinru Ji, Zheru Qiu

Silicon nitride (Si3N4) photonic integrated circuits (PICs) offer significant advantages over traditional silicon photonics, including low loss and superior power handling at optical communication wavelength bands. To facilitate high-density integration an ...

2024

Hybrid integrated multi-lane erbium-doped Si3N4 waveguide amplifiers

Tobias Kippenberg, Xinru Ji, Zheru Qiu

We present the integration of four individual erbium-doped waveguide optical amplifiers on a Si3N4 photonic integrated circuit hybrid integrated with a four-lane semiconductor pump laser diode chip. Each amplifier achieves 15 dB on-chip gain. ...

Optical Society of America2024

Low-temperature and hydrogen-free silicon dioxide cladding for next-generation integrated photonics

Tobias Kippenberg, Xinru Ji, Anat Siddharth, Zheru Qiu, Zihan Li

We demonstrate a process for hydrogen-free low-loss silicon oxide (SiO2) films deposited using S iCl4 and O 2 as precursors. A wide low-loss window from 1260 nm to 1625 nm is achieved at a deposition temperature of 300 ◦C, essential for next generation pho ...

Optical Society of America2024

Large-Scale Photonic Chip Based Pulse Interleaver for Low-Noise Microwave Generation

Rui Ning Wang, Tobias Kippenberg, Xinru Ji, Zheru Qiu

We demonstrate a 64-times multiplication of a mode-locked laser’s 217 MHz pulse repetition rate to 14 GHz using an integrated Si3N4 interleaver. Six cascaded stages of Mach-Zehnder interferometers with up to 33 cm long optical delay lines are fully integra ...

Springer Science and Business Media Deutschland GmbH2024

Lithium Tantalate Photonic Integrated Circuits (Student Paper)

Tobias Kippenberg, Mikhail Churaev, Xinru Ji, Zihan Li

We demonstrate a wafer-scale lithium tantalate photonic platform with loss as low as 5.5 dB m(-1). Mach-Zehnder modulators with a 40 GHz electro-optical bandwidth and a 1.96 V center dot cm voltage-length product, along with microresonators supporting diss ...

Springer Nature2024

Full C-band tunable integrated Erbium lasers via wafer-scale fabrication

Rui Ning Wang, Tobias Kippenberg, Xinru Ji, Anat Siddharth, Zheru Qiu

We demonstrate an integrated Erbium-based tunable laser using wafer-scale fabrication and ion implantation of silicon nitride photonic integrated circuits, and achieve single-frequency lasing tunable from 1530 nm to 1575 nm covering the entire optical C-ba ...

Institute of Electrical and Electronics Engineers Inc.2024

Lithium tantalate photonic integrated circuits for volume manufacturing

Tobias Kippenberg, Kai Huang, Chen Yang, Mikhail Churaev, Xinru Ji, Yang Chen, Zihan Li, Alisa Davydova, Xi Wang, Junyin Zhang

Electro-optical photonic integrated circuits (PICs) based on lithium niobate (LiNbO3) have demonstrated the vast capabilities of materials with a high Pockels coefficient1,2. They enable linear and high-speed modulators operating at complementary metal–oxi ...

2024

A hertz-linewidth Erbium laser based on photonic integrated circuits

Rui Ning Wang, Tobias Kippenberg, Xinru Ji, Zheru Qiu

We demonstrate a photonic integrated circuit-based Erbium laser by endowing an ultralow-loss silicon nitride integrated optical cavity with Erbium-based gain. The free-running laser achieves 50 Hz intrinsic linewidth, 17 mW output power, and 40 nm waveleng ...

Optical Society of America2023

Edge state optical frequency combs in the microresonator based Su-Schrieffer-Heeger model

Tobias Kippenberg, Xinru Ji, Alexey Tikan, Aleksandr Tusnin

We demonstrate the first observation of optical frequency combs at the edge state of the Su-Schrieffer-Heeger model. We show soliton-induced edge-bulk interaction and edge-state hopping. ...

Optical Society of America2023

A Photonic Integrated High-power Soliton Microcomb Generator

Rui Ning Wang, Tobias Kippenberg, Andrey Voloshin, Xinru Ji, Zheru Qiu

We demonstrate a compact soliton microcomb light source. The soliton is generated from a Kerr microresonator and amplified by an erbium-implanted gain section integrated on the same photonic chip. We achieved an output power of 7.9 mW at a compact device f ...

Optical Society of America2023

Stabilization of SiN Kerr Solitons for the calibration of astronomical spectrographs

Rui Ning Wang, Tobias Kippenberg, Miles Henry Anderson, Xinru Ji, Anat Siddharth

We demonstrate a stabilization scheme for dissipative Kerr solitons in SiN-resonators achieving high comb stability and long-term operation. Measuring 10Hz level absolute Kerr comb line stability (at 1 second) close to the pump, resulting in kHz level stab ...

Optical Society of America2023