arXiv subjects

Gregory Moille

Publications and source records attributed to Gregory Moille.

At least 19 recordsLinked to original sources

arXiv2026

All-optical Synchronization of Breather Solitons in a Kerr Microresonator

Microresonator Kerr solitons are promising candidates for the realization of miniaturized on-chip optical frequency combs. For specific system parameters, these solitons are associated with oscillatory instabilities, leading to breathing dynamics characterized by periodically modulated temporal and spectral profiles. In this regime, the solitons form a frequency comb comprised of primary comb lines surrounded by sidebands separated by the breathing frequency. Here, we numerically and experimentally demonstrate that the breathing sidebands can be all-optically synchronized to a weak monochromatic laser injected into the cavity, thus providing direct control of the soliton oscillation frequency. We judiciously characterize the synchronization process, and show that it is accompanied by a strong reduction of noise in the soliton's breathing. Our results provide fundamental insights on oscillatory dissipative structures, and could enable new forms of composite optical frequency combs.

physics.optics↗

arXiv2026

Single-Shot Realization of 10000-Mode Octave-Spanning Artificial Gauge Fields

Artificial gauge fields (AGFs) enable photons and other bosons to emulate fermionic phenomena such as chiral edge transport and quantum Hall phases; however, existing theories and realizations remain confined to narrow bandwidths under single-mode approximation. We introduce a general theoretical framework for ultra-broadband, multi-modal dispersion-corrected AGFs in both linear and nonlinear regimes. Using integrated photonics, we realize over 100 distinct AGFs hosting more than 10,000 modes across nearly an optical octave -- the first frequency-comb realization of the integer quantum Hall model for photons. Leveraging Kerr nonlinearity, we achieve single-shot AGF control beyond waveguide dispersion, robust to wafer-scale fabrication variations. Our results establish a new regime of ultra-broadband multimodal AGFs, opening pathways to exotic dispersion-corrected AGF dynamics and simulations, as well as volume-manufacturable device functionalities such as waveguide-dispersion-resilient photonic circuits, and AGF-enabled programmable nonlinear and quantum optics and optoelectrics.

physics.optics↗

arXiv2026

Broadband Chromatic Dispersion of Thermo-refractive Coefficients and its Impact in Silicon Nitride Nonlinear Photonics

The thermo-refractive effect is a cornerstone of frequency and phase tuning in photonic integrated circuits. In particular, it enables control of phase-matching for integrated nonlinear processes. Chromatic dispersion of the group and effective refractive indices and modal confinement are standard considerations in design, but material thermo-refractive coefficients (TRCs) are typically taken to be fixed for the guiding and cladding materials. Here, we demonstrate that the assumption of non-dispersive TRCs across an octave of bandwidth between the telecom and visible results in a significant discrepancy between measured and simulated resonance frequencies of an integrated Si3N4/SiO2 microring resonator. We uncover a 7 % variation in Si3N4 and SiO2 material TRCs across this range, finding that the variation of dneff /dT from material TRCs is 1.3 times that from modal confinement. This accurately matches a temperature-dependent Lorentz oscillator model describing their chromatic dispersion. By integrating these dispersive TRCs into a multi-physics finite-element model, we achieve precise correspondence with experimentally measured temperature-dependent resonance frequency shifts across the octave, including in the context of second harmonic generation devices. Our results provide a physical framework and a universal predictive workflow for the design of high-efficiency, multi-wavelength nonlinear optical processes, fundamentally improving the thermal control of integrated photonic devices.

physics.optics↗

arXiv2026

Microring Resonator Dispersion Metrology with Neural Networks

Precise knowledge of resonator dispersion, from both geometric and material contributions, is essential for reliable high-performance nonlinear integrated photonics devices, such as optical parametric oscillators, frequency doublers, and integrated optical frequency combs. However, direct measurements at the fabrication level provide limited knowledge, whether through destructive cross-section imaging or non-destructive ellipsometry, while complete optical characterization that enables precise dispersion metrology is time-consuming and poorly suited for mass-scale foundry fabrication. In this work, we develop a machine learning framework to solve three complementary problems: (i) predicting resonator geometric dimensions, (ii) identifying the correct material dispersion, and last, but not least, (iii) precisely reconstructing the integrated dispersion spectrum directly from ring dimensions. These three neural networks together enable both inverse and forward characterization of microring resonators. Using numerically generated datasets based on Sellmeier-type material models, we demonstrate <1 nm ring dimension prediction accuracy without noise, <8 nm prediction accuracy with ~45 dispersion samples under a realistic frequency measurement noise level (50 MHz), and ~16 nm prediction accuracy at a higher noise level (200 MHz). The Sellmeier model classification exceeds 99% accuracy in all cases. Importantly, dispersion sampled far from the pump resonances proves most informative, reducing full-spectrum characterization requirements. The forward-prediction network reconstructs dispersion spectra from the ring dimensions with high accuracy. Our results highlight the potential of machine learning applied to dispersion data as a rapid, non-destructive tool for wafer-scale quality control and process monitoring in photonic foundries.

physics.optics↗

arXiv2025

Quantum Metamorphosis: Programmable Emergence and the Breakdown of Bulk-Edge Dichotomy in Multiscale Systems

Multiscale synergy -- the interplay of a system's distinct characteristic length, time, and energy scales -- is becoming a unifying thread across many contemporary branches of science. Ranging from moir\'e and super-moir\'e materials and cold atoms to DNA-templated superlattices and nested photonic networks, multiscale synergy produces behaviors not obtainable at any single scale alone. Yet a general framework that programs cross-scale interplay to steer spectra, transport, and topology has been missing. Here, we elevate multiscale synergy from a byproduct to a general design principle for emergent phenomena. Specifically, we introduce a scale-programmable framework for hierarchically nested lattices (HNLs) that can host quantum metamorphosis (QuMorph) -- a continuous evolution between system-dependent features governed by a dimensionless tunable parameter $\alpha$ (the relative hopping). To exemplify, we show an HNL, in which as $\alpha$ changes, the spectrum metamorphoses from integer quantum Hall-like to anomalous quantum Hall-like, passing through a cocoon regime with proliferating mini-gaps. This multiscale mixing yields multiple novel phenomena, including hybrid edge-bulk states, scale-dependent topology, topologically embedded flat bands, and isolated edge bands. We propose a feasible photonic implementation using commercially available coupled-resonator arrays, outline spatial-spectral signatures to map QuMorph, and explore applications for multi-timescale nonlinear optics. Our work establishes a scalable and programmable paradigm for engineering multiscale emergent phenomena.

physics.optics↗

arXiv2025

Toward Chaotic Group Velocity Hopping of an On-Chip Dissipative Kerr Soliton

Chaos enables randomness-based applications, particularly in photonic systems. Integrated optical frequency combs (microcombs) have previously been observed in either chaotic modulation instability or stable, low-noise dissipative Kerr soliton (DKS) regimes. In this work, we demonstrate a new microcomb state where a single DKS exhibits chaotic behavior. By phase modulating the Kerr-induced synchronization (KIS) between a DKS and an externally injected reference laser, we observe chaotic group velocity hopping of the soliton, causing random transitions of the repetition rate. Using a chip-integrated octave-spanning microcomb, we experimentally validate the second-order Adler equation describing KIS, allowing us to predict and demonstrate this chaotic DKS hopping. This work connects nonlinear dynamics with optical soliton physics, providing a deterministic framework for triggering microcomb chaos in the solitonic state.

physics.optics↗

arXiv2025

300 mm Wafer-Scale SiN Platform for Broadband Soliton Microcombs Compatible with Alkali Atomic References

Chip-integrated optical frequency combs (OFCs) based on Kerr nonlinear resonators are of great significance given their scalability and wide range of applications. Broadband on-chip OFCs reaching visible wavelengths are especially valuable as they address atomic clock transitions that play an important role in position, navigation, and timing infrastructure. Silicon nitride (SiN) deposited via low pressure chemical vapor deposition (LPCVD) is the usual platform for the fabrication of chip-integrated OFCs, and such fabrication is now standard at wafer sizes up to 200 mm. However, the LPCVD high temperature and film stress poses challenges in scaling to larger wafers and integration with electronic and photonic devices. Here, we report the linear performance and broadband frequency comb generation from microring resonators fabricated on 300 mm wafers at AIM Photonics, using a lower temperature, lower stress plasma enhanced chemical vapor deposition process that is suitable for thick ($\approx$ 700 nm) SiN films and compatible with electronic and photonic integration. The platform exhibits consistent insertion loss, high intrinsic quality factor, and thickness variation of $\pm$2 % across the whole 300 mm wafer. We demonstrate broadband soliton microcomb generation with a lithographically tunable dispersion profile extending to wavelengths relevant to common alkali atom transitions. These results are a step towards mass-manufacturable devices that integrate OFCs with electronic and active photonic components, enabling advanced applications including optical clocks, LiDAR, and beyond.

physics.optics↗

arXiv2025

Multi-timescale frequency-phase matching for high-yield nonlinear photonics

Integrated nonlinear photonic technologies, even with state-of-the-art fabrication with only a few nanometer geometry variations, face significant challenges in achieving wafer-scale yield of functional devices. A core limitation lies in the fundamental constraints of energy and momentum conservation laws. Imposed by these laws, nonlinear processes are subject to stringent frequency and phase matching (FPM) conditions that cannot be satisfied across a full wafer without requiring a combination of precise device design and active tuning. Motivated by recent theoretical and experimental advances in integrated multi-timescale nonlinear systems, we revisit this long-standing limitation and introduce a fundamentally relaxed and passive framework: nested frequency-phase matching. As a prototypical implementation, we investigate on-chip multi-harmonic generation in a two-timescale lattice of commercially available silicon nitride (SiN) coupled ring resonators, which we directly compare with conventional single-timescale counterparts. We observe distinct and striking spatial and spectral signatures of nesting-enabled relaxation of FPM. Specifically, for the first time, we observe simultaneous fundamental, second, third, and fourth harmonic generation, remarkable 100 percent multi-functional device yield across the wafer, and ultra-broad harmonic bandwidths. Crucially, these advances are achieved without constrained geometries or active tuning, establishing a scalable foundation for nonlinear optics with broad implications for integrated frequency conversion and synchronization, self-referencing, metrology, squeezed light, and nonlinear optical computing.

physics.optics↗

arXiv2025

Highly squeezed nanophotonic quantum microcombs with broadband frequency tunability

Squeezed light offers genuine quantum advantage in enhanced sensing and quantum computation; yet the level of squeezing or quantum noise reduction generated from nanophotonic chips has been limited. In addition to strong quantum noise reduction, key desiderata for such a nanophotonic squeezer include frequency agility or tunability over a broad frequency range, and simultaneous operation in many distinct, well-defined quantum modes (qumodes). Here we present a strongly overcoupled silicon nitride squeezer based on a below-threshold optical parametric amplifier (OPA) that produces directly detected squeezing of 5.6 dB $\pm$ 0.2 dB, surpassing previous demonstrations in both continuous-wave and pulsed regimes. We introduce a seed-assisted detection technique into such nanophotonic squeezers that reveals a quantum frequency comb (QFC) of 16 qumodes, with a separation of 11~THz between the furthest qumode pair, while maintaining a strong squeezing. Additionally, we report spectral tuning of a qumode comb pair over one free-spectral range of the OPA, thus bridging the spacing between the discrete modes of the QFC. Our results significantly advance both the generation and detection of nanophotonic squeezed light in a broadband and multimode platform, establishing a scalable, chip-integrated path for compact quantum sensors and continuous-variable quantum information processing systems.

physics.optics↗

arXiv2025

On-chip multi-timescale spatiotemporal optical synchronization

Mode-locking mechanisms are key resources in nonlinear optical phenomena, such as micro-ring solitonic states, and have transformed metrology, precision spectroscopy, and optical communication. However, despite significant efforts, mode-locking has not been demonstrated in the independently tunable multi-timescale regime. Here, we vastly expand the nonlinear mode-locking toolbox into multi-timescale synchronization on a chip. We use topological photonics to engineer a 2D lattice of hundreds of coupled silicon nitride ring resonators capable of hosting nested mode-locked states with a fast (near 1 THz) single-ring and a slow (near 3 GHz) topological super-ring timescales. We demonstrate signatures of multi-timescale mode-locking including quadratic distribution of the pump noise with the two-time azimuthal mode dimensions, as expected by mode-locking theory. Our observations are further corroborated by direct signatures of the near-transform-limit repetition beats and the formation of the temporal pattern on the slow timescale. Moreover, we show that these exotic properties of edge-confined mode-locked states are in sharp contrast to bulk and single-ring counterparts and establish a clear pathway for their identification. Our unprecedented demonstration of mode-locking in topological combs unlocks the implementation of lattice-scale synchronization and independently tunable multi-timescale mode-locking phenomena, also the exploration of the fundamental nonlinearity-topology interplay on a chip.

physics.optics↗

arXiv2024

On-Chip Parametric Synchronization of a Dissipative Kerr Soliton Microcomb

Synchronization of oscillators is ubiquitous in nature. Often, the synchronized oscillators couple directly, yet in some cases synchronization can arise from their parametric interactions. Here, we theoretically predict and experimentally demonstrate the parametric synchronization of a dissipative Kerr soliton frequency comb. We specifically show that the parametric interaction between the soliton and two auxiliary lasers permits the entrainment of the frequency comb repetition rate. Besides representing the first prediction and demonstration of parametric synchronization of soliton frequency combs, our scheme offers significant flexibility for all-optical metrological-scale stabilization of the comb.

physics.optics↗

arXiv2024

All-Optical Azimuthal Trapping of Dissipative Kerr Multi-Solitons for Relative Noise Suppression

Temporal cavity solitons, or dissipative Kerr solitons (DKS) in integrated microresonators, are essential for deployable metrology technologies. Such applications favor the lowest noise state, typically the single-DKS state where one soliton is in the resonator. Other multi-DKS states can also be reached, offering better conversion efficiency and thermal stability, potentially simplifying DKS-based technologies. Yet they exhibit more noise due to relative soliton jitter, and are usually not compatible with targeted applications. We demonstrate that Kerr-induced synchronization, an all-optical trapping technique, can azimuthally pin the multi-DKS state to a common reference field. This method ensures repetition rate noise independent of the number of solitons, making a multi-DKS state indistinguishable from a single-DKS state in that regard, akin to trapped-soliton molecule behavior. Supported by theoretical analysis and experimental demonstration in an integrated microresonator, this approach provides metrological capacity regardless of the number of cavity solitons, benefiting numerous DKS-based metrology applications.

physics.optics↗

arXiv2024

All-Optical Noise Quenching of An Integrated Frequency Comb

Integrated frequency combs promise transformation of lab-based metrology into disruptive real-world applications. These microcombs are, however, sensitive to stochastic thermal fluctuations of the integrated cavity refractive index, with its impact becoming more significant as the cavity size becomes smaller. This tradeoff between microcomb noise performance and footprint stands as a prominent obstacle to realizing applications beyond a controlled lab environment. Here, we demonstrate that small footprint and low noise become compatible through the all-optical Kerr-induced synchronization (KIS) method. Our study unveils that the phase-locking nature of the synchronization between the cavity soliton and the injected reference pump laser enables the microcomb to no longer be limited by internal noise sources. Instead, the microcomb noise is mostly limited by external sources, namely, the frequency noise of the two pumps that doubly pin the microcomb. First, we theoretically and experimentally show that the individual comb tooth linewidths of an octave-spanning microcomb remain within the same order-of-magnitude as the pump lasers, contrary to the single-pumped case that exhibits a more than two order-of-magnitude increase from the pump to the comb edge. Second, we theoretically show that intrinsic noise sources such as thermorefractive noise in KIS are quenched at the cavity decay rate, greatly decreasing its impact. Experimentally, we show that even with free-running lasers, the KIS microcomb can exhibit better repetition rate noise performance than the predicted thermorefractive noise limitation in absence of KIS.

physics.optics↗

arXiv2024

Terahertz Voltage-controlled Oscillator from a Kerr-Induced Synchronized Soliton Microcomb

The generation of controlled and arbitrarily tunable terahertz radiation, essential for many applications, has proven challenging due to the complexity of experimental setups and fabrication techniques. We introduce a new strategy involving control over a terahertz repetition rate integrated frequency comb, using Kerr-induced synchronization, that results in a terahertz-voltage-controlled oscillator. By modulating the reference laser, we can transfer any microwave waveform onto the microcomb repetition rate via a linear transfer function based on optical frequency division. The resulting frequency comb with a terahertz carrier can be created using integrated components, with a bandwidth constrained only by the synchronization bandwidth and high coherence resulting from the low-noise soliton microcomb in the Kerr-induced synchronized state.

physics.optics↗

arXiv2024

On-chip Kerr parametric oscillation with integrated heating for enhanced frequency tuning and control

Nonlinear microresonators can convert light from chip-integrated sources into new wavelengths within the visible and near-infrared spectrum. For most applications, such as the interrogation of quantum systems with specific transition wavelengths, tuning the frequency of converted light is critical. Nonetheless, demonstrations of wavelength conversion have mostly overlooked this metric. Here, we apply efficient integrated heaters to tune the idler frequency produced by Kerr optical parametric oscillation in a silicon-nitride microring across a continuous 1.5 terahertz range. Finally, we suppress idler frequency noise between DC and 5 kHz by several orders of magnitude using feedback to the heater drive.

physics.optics↗

arXiv2024

Broadband Visible Wavelength Microcomb Generation In Silicon Nitride Microrings Through Air-Clad Dispersion Engineering

The development of broadband microresonator frequency combs at visible wavelengths is pivotal for the advancement of compact and fieldable optical atomic clocks and spectroscopy systems. Yet, their realization necessitates resonators with anomalous dispersion, an arduous task due to the prevailing normal dispersion regime of materials within the visible spectrum. In this work, we evince that silicon nitride microring resonators with air cladding on top and sides -- a deviation from the frequently employed silica-embedded resonators -- allows for the direct generation of broadband microcombs in the visible range. We experimentally demonstrate combs pumped at 1060~nm (283~THz) that reach wavelengths as short as 680~nm (440 THz), and combs pumped at 780~nm (384 THz) that reach wavelengths as short as 630 nm (475 THz). We further show through simulations that microcombs extending to wavelengths as low as 461 nm (650 THz) should be accessible in this platform.

physics.optics↗

arXiv2024

Versatile Optical Frequency Division with Kerr-induced Synchronization at Tunable Microcomb Synthetic Dispersive Waves

Kerr-induced synchronization (KIS) provides a new key tool for the control and stabilization of the repetition rate of a cavity soliton frequency comb. It enables direct external control of a given comb tooth of a dissipative Kerr soliton (DKS) thanks to its capture by an injected reference laser. Efficient KIS requires its coupling energy to be sufficiently large, and hence both the comb tooth and intracavity reference power must be optimized, which can be achieved through higher-order dispersion that enables phase-matched dispersive waves (DWs), where comb teeth are on resonance. However, such a design is highly restrictive, preventing arbitrary use of reference wavelengths away from the DW(s). In particular, for large spectral separations from the main pump the cavity dispersion yields large detuning between comb teeth and their respective cavity resonances, thereby decreasing the coupling energy and rendering KIS to be highly inefficient or practically impossible. Here, we demonstrate an alternative KIS method where efficient synchronization can be tailored at arbitrary modes as needed. Using a multi-color DKS created from multi-pumping a microresonator, a synthetic DW at the second-color wavepacket can be selectively created where otherwise dispersion is far too large for KIS to be experimentally feasible. Since a unique group velocity for both colors exists thanks to cross-phase modulation, the repetition rate disciplining of the secondary color wavepacket through its KIS automatically translates into the DKS microcomb control. We first investigate this color-KIS phenomenon theoretically, and then experimentally demonstrate its control and tuning of the soliton microcomb repetition rate. As a consequence, we demonstrate optical frequency division that is uncoupled from the main pump that generates the DKS.

physics.optics↗

arXiv2024

AC-Josephson Effect and Sub-Comb Mode-Locking in a Kerr-Induced Synchronized Cavity Soliton

Kerr-induced synchronization (KIS) [1] involves the capture of a dissipative Kerr soliton (DKS) microcomb [2] tooth by a reference laser injected into the DKS resonator. This phase-locking behavior is described by an Adler equation whose analogous form describes numerous other physical systems [3], such as Josephson junctions [4]. We present an AC version of KIS whose behavior is similar to microwave-driven Josephson junctions, where periodic synchronization occurs as so-called Shapiro steps. We demonstrate consistent results in the AC-KIS dynamics predicted by the Adler model, Lugiato-Lefever equation, and experimental data from a chip-integrated microresonator system. The (integer) Shapiro steps in KIS can simply be explained as the sideband created through the reference laser phase modulation triggering the synchronization. Notably, our optical system allows for easy tuning of the Adler damping parameter, enabling the further observation of fractional-Shapiro steps, where the synchronization happens at a fraction of the driving microwave frequency. Here, we show that the comb tooth is indirectly captured thanks to a four-wave mixing Bragg-scattering process, leading to sub-comb mode-locking, and we demonstrate this experimentally through noise considerations. Our work opens the door to the study of synchronization phenomena in the context of microresonator frequency combs, synthesis of condensed-matter state analogues with DKSs, and the use of the fractional Shapiro steps for flexible and tunable access to the KIS regime.

physics.optics↗