We demonstrated a mode-locked microcomb generation in a hybrid cavity. With the simultaneously lasing and nonlinear oscillation process, the high-coherence microcomb can be generated in a turnkey manner and free-running over 24 hours.

We demonstrate over 200 Tbps transmission with only 16 self-injection locking microcomb channels. Our results achieve a record-high 70 Gbaud rate in microcomb-based transmission, promising Pbps-scale deployment within a compact system configuration.

The generation, processing, and measurement of microwave signals using optoelectronic technology on compact chips represent a significant trend in the evolution of microwave photonics (MWP). Among various platforms, silicon photonics has emerged as a leading choice, primarily due to its compatibility with established complementary metal-oxide-semiconductor (CMOS) processes. This compatibility enables the complete integration of high-performance radio frequency (RF) links while addressing key challenges such as size, power consumption, cost, and reliability. In this article, we review recent advancements in silicon-integrated microwave photonics, focusing on the developments of device-level integration and system-level applications. At the device level, we highlight critical innovations in silicon-based passive and active components towards MWP concerns, including ultralow-loss waveguides, high-fitness micro rings, large-bandwidth/high-linearity electro-optic modulators, hybrid/heterogeneous integrated lasers and amplifiers on silicon, frequency combs, and more. These breakthroughs form the basic foundation for advancing MWP system-level implementation. At the system-level applications, we concentrate on integrated MWP systems with diverse functionalities on silicon chips, including microwave signal generation, processing, programmable circuits, and measurement systems. Finally, we discuss current challenges and provide insights into the future of silicon-integrated MWP.

We achieved a microwave photonic RF receiver with pre-amplification on Er-doped lithium niobate platform for the first time. This scheme exhibits improved signal recovery quality compared to off-chip gain. © 2025 The Author(s)

An integrated oscillator is constructed by butt-coupling a gain chip to a mi-croresonator with internal reflection, enabling the hybridization of lasing and nonlinear oscillation processes. Microcomb evolution is observed experimentally within the hybrid oscillator.

Modulation and amplification are two fundamental processes in optoelectronics. While discrete implementations have achieved widespread success, the challenge of monolithically integrating sufficient gain and electro-optic bandwidth remains a significant barrier, limiting optical systems' miniaturization and scalability. We unify these two functions in the Er-doped thin-film lithium niobate (Er:TFLN) platform, achieving a record-high internal net gain of 38 dB in a 9.16-cm-long waveguide amplifier. Meanwhile, leveraging the host material's strong Pockels effect, we realize ultra wide-range electro-optic modulation with a bandwidth of 53 GHz and operation up to 170 GHz, fabricated alongside waveguide amplifiers using a zero-change process. Additionally, we validate this functional fusion through two signal processing scenarios: self-amplified digital signal encoding and pre-amplified broadband radio frequency front-end receiving, demonstrating improved signal recovery quality compared to off-chip gain. The modulation-amplification integration holds broad potential for increasing system complexity and network depth in applications such as optical interconnections, Lidar, and microwave photonics.

Microcavity optical frequency combs (microcombs) are compact, coherent light sources whose chip-scale integrability is poised to drive advances in metrology, communications, and sensing. Among available microcomb generation methods, hybrid cavities uniquely co-locate gain and Kerr dynamics, where the lasing mode directly resonates in the nonlinear microcavity, simultaneously enabling self-sustained and highly efficient microcomb generation. However, their implementation is often limited by partial integration or the need for external injection, which complicates operation architecture, raises power and hampers system miniaturization. In this work, we present a fully integrated hybrid cavity for self-sustained microcomb generation, relying solely on the co-oscillation of lasing and Kerr nonlinearity without external driving. The system collapses the pump laser, nonlinear resonator and feedback loops into a minimalist on-chip two-element cavity, consisting of a high-Q microresonator with engineered intracavity reflection and a reflective semiconductor optical amplifier (RSOA). The scheme delivers self-starting operation and stable performance without active feedback. The generated coherent microcomb achieves intrinsic linewidths below 1 kHz and integrated linewidths around 100 kHz, with self-sustained operation exceeding 24 hours. This ultra-compact architecture provides a practical path toward scalable, coherent multi-wavelength sources for integrated photonic systems.

Based on an AI-accelerated silicon slow-light modulator chip, we realize 400 Gbps PAM-4 optical transmission per wavelength in a standard silicon photonic platform for the first time, leading to a total data capacity of 3.2 Tbps with an on-chip data-rate density of 1.6 Tb/s/mm(2). (c) 2025 The Author(s)

Silicon photonics is a promising platform for the extensive deployment of optical interconnections, with the feasibility of low-cost and large-scale production at the wafer level. However, the intrinsic efficiency-bandwidth trade-off and nonlinear distortions of pure silicon modulators result in the transmission limits, which raises concerns about the prospects of silicon photonics for ultrahigh-speed scenarios. Here, we propose an artificial intelligence (AI)-accelerated silicon photonic slow-light technology to explore 400 Gbps/λ and beyond transmission. By utilizing the artificial neural network, we achieve a data capacity of 3.2 Tbps based on an 8-channel wavelength-division-multiplexed silicon slow-light modulator chip with a thermal-insensitive structure, leading to an on-chip data-rate density of 1.6 Tb/s/mm2. The demonstration of single-lane 400 Gbps PAM-4 transmission reveals the great potential of standard silicon photonic platforms for next-generation optical interfaces. Our approach increases the transmission rate of silicon photonics significantly and is expected to construct a self-optimizing positive feedback loop with computing centers through AI technology.

The exponential growth of data capacity in intelligent terminals drives higher data traffic toward network edges. Compact I/O systems are essential to support space-constrained infrastructures at the computing edges or modular data centers. However, scaling high-capacity transmission via increasing physical channels is constrained by limited source coherence and low carrier-to-noise ratios (OCNR), hindering lightweight, efficient applications like distributed edge computing. Here, we exploit an integrated self-injection-locked dark-pulse microcomb to achieve 1 Tbps/λ/core transmission and characterize the constraints among OCNR, linewidth, and transmission rate. Furthermore, a multi-dimensional transmission architecture for multi-nodes aggregation is explored, boosting the transmission rate to 200 Tbps with 16 comblines at 70 Gbaud. Combining with integrated waveshapers and semiconductor optical amplifiers, a chip-level parallel carrier generator is explored, reducing system size a hundredfold while delivering 5 Tbps. Our results highlight significant potential for compact and resource-conserving transmission systems in data centers and distributed high performance computing applications. The exponential growth of data traffic demands efficient transmission systems. Here, authors exploit a self-injection-locked microcomb to achieve high-capacity optical transmission, demonstrating a compact, lightweight system with potential for data centers and edge computing applications.

We demonstrate the first self-amplified high-speed integrated photonic transmitter based on Erbium-doped lithium niobate platform. The proposed system integrates optical gain and electro-optic dynamics monolithically, supporting up to 170 GHz ultra-high bandwidth electro-optic operation.

The human eye achieves high resolution and energy efficiency through adaptive focusing on pertinent details. This natural capability sets a benchmark that current machine vision systems struggle to emulate due to rigid parallel-sensing mechanisms. Efforts to achieve retinal-level resolution through brute-force scaling of channels can lead to prohibitive cost, complexity, and power consumption. Here, we address this bottleneck with a retina-inspired chip-scale LiDAR architecture featuring dynamic gazing capability. By synergizing an agile external cavity laser with reconfigurable electro-optic frequency combs, our integrated photonic platform enables coherent LiDAR with parallel, reconfigurable channels, allocating sensing resources to critical regions without global oversampling. This hardware-efficient design enables real-time comb-based 4D imaging at 0.012° beyond-retinal resolution and supports 4D-plus imaging through cooperative sensing with a camera. With its beyond-retinal resolution, dynamic gazing capability, and scalable chip-level manufacturability, this technology offers a path toward lightweight, high-performance perception across aerial, terrestrial, and marine autonomous systems. Inspired by the human eye’s dynamic focusing, this work demonstrates an integrated bionic LiDAR that achieves energy-efficient, adaptive 4D imaging, offering a compact and scalable path toward intelligent machine vision.

With the rapid advancement of integrated photonic systems,rare-earth-doped waveguide amplifiers have emerged as a critical research focus due to their low-noise characteristics,extended luminescence lifetimes,and superior thermal stability.This article provides a comprehensive review of recent progress in rare-earth-doped waveguide amplifiers,exploring their fundamental photonic emission mechanisms,pivotal technological advancements,and system-level applications.We elucidate the impact of pumping schemes,material systems,and waveguide geometries on gain performance,establishing design principles for performance optimization.Furthermore,we demonstrate the versatility of rare-earth-doped waveguide amplifiers in enabling high-speed coherent communications,on-chip femtosecond pulse amplification,and high-energy Q-switched lasing,underscoring their transformative potential in broadband optical networks and high-power photonic-integrated systems.Future research will prioritize multi-ion co-doping strategies,dynamically tunable gain spectra,and high-efficiency on-chip pumping techniques to drive breakthroughs in integrated photonic devices and expand their application frontiers across next-generation communication and sensing platforms.

Light detection and ranging (LiDAR) is a ubiquitous tool to provide precise spatial awareness in various perception environments. A bionic LiDAR that can mimic human-like vision by adaptively gazing at selected regions of interest within a broad field of view is crucial to achieve high-resolution imaging in an energy-saving and cost-effective manner. However, current LiDARs based on stacking fixed-wavelength laser arrays and inertial scanning have not been able to achieve the desired dynamic focusing patterns and agile scalability simultaneously. Moreover, the ability to synchronously acquire multi-dimensional physical parameters, including distance, direction, Doppler, and color, through seamless fusion between multiple sensors, still remains elusive in LiDAR. Here, we overcome these limitations and demonstrate a bio-inspired frequency-modulated continuous wave (FMCW) LiDAR system with dynamic and scalable gazing capability. Our chip-scale LiDAR system is built using hybrid integrated photonic solutions, where a frequency-chirped external cavity laser provides broad spectral tunability, while on-chip electro-optic combs with elastic channel spacing allow customizable imaging granularity. Using the dynamic zoom-in capability and the coherent FMCW scheme, we achieve a state-of-the-art resolution of 0.012 degrees, providing up to 15 times the resolution of conventional 3D LiDAR sensors, with 115 equivalent scanning lines and 4D parallel imaging. We further demonstrate cooperative sensing between our adaptive coherent LiDAR and a camera to enable high-resolution color-enhanced machine vision.

We propose the Sagnac ring with wide-band, reliable reflection f or self-injection locking, achieving lasers with an intrinsic linewidth as low as 24.38 Hz and demonstrating mode-locked microcomb generation at different resonances.

Self-injection locking has emerged as a crucial technique for coherent optical sources, spanning from narrow linewidth lasers to the generation of localized microcombs. This technique involves key components, namely a laser diode and a high-quality cavity that induces narrow-band reflection back into the laser diode. However, in prior studies, the reflection mainly relied on the random intracavity Rayleigh backscattering, rendering it unpredictable and unsuitable for large-scale production and wide-band operation. In this work, we present a simple approach to achieve reliable intracavity reflection for self-injection locking to address this challenge by introducing a Sagnac loop into the cavity. This method guarantees robust reflection for every resonance within a wide operational band without compromising the quality factor or adding complexity to the fabrication process. As a proof of concept, we showcase the robust generation of narrow linewidth lasers and localized microcombs locked to different resonances within a normal-dispersion microcavity. Furthermore, the existence and generation of localized patterns in a normal-dispersion cavity with broadband forward–backward field coupling is first proved, as far as we know, both in simulation and in experiment. Our research offers a transformative approach to self-injection locking and holds great potential for large-scale production.

We demonstrate an erbium-doped lithium niobate on insulator waveguide amplifier which achieved the highest internal net gain of 38 dB with a 9.16 cm waveguide at 1531.7 nm.

Integrated optical nonlinearities have spawned many new technologies such as optical parametric oscillators and microcombs. Despite remarkable achievements, optical parametric oscillation (OPO) and microcomb generation remain challenging for foundry-available silicon photonics. Silicon-photonic platform provides mature CMOS manufacturing process and relatively high nonlinear coefficient. However, the nonlinear absorption at near-infrared telecommunication band hinders the effective nonlinear response on silicon photonics. In addition, the 220 nm thick Si layer is unsuitable for anomalous dispersion waveguides, which is necessary for OPO process. In this work, a concentric microresonator with the PIN doping structure is designed to solve these two problems. Under reverse bias on the designed PIN structure, the generated free carriers are effectively migrated to weaken the free carrier absorption. Local anomalous dispersion is induced by the designed concentric structure. Optical parametric oscillation is theoretically analyzed and 10 OPO sidebands are experimentally generated with a single pump. Our design verifies the ability of dispersion engineered nonlinear oscillators in C-band on foundry-available silicon photonic platform.

Silicon modulators are key components to support the dense integration of electro-optic functional elements for various applications. Despite numerous advances in promoting the modulation speed, a bandwidth ceiling emerges in practices and becomes an obstacle toward Tbps-level throughput on a single chip. Here, we demonstrate a compact pure silicon modulator that shatters present bandwidth ceiling to 110 gigahertz. The proposed modulator is built on a cascade corrugated waveguide architecture, which gives rise to a slow-light effect. By comprehensively balancing a series of merits, the modulators can benefit from the slow light for better efficiency and compact size while remaining sufficiently high bandwidth. Consequently, we realize a 110-gigahertz modulator with 124-micrometer length, enabling 112 gigabits per second on-off keying operation. Our work proves that silicon modulators with 110 gigahertz are feasible, thus shedding light on its potentials in ultrahigh bandwidth applications such as optical interconnection and photonic machine learning.

Massively parallel optical chaotic sources with large bandwidth are demonstrated based on chaotic microcombs in the AlGaAsOI platform. 30-channel parallel random bit generation with 30 Gbit/s per channel is realized based on the chaotic source.