The utilization of Kerr nonlinearity in lithium niobate has been extensively investigated over the years. Nevertheless, the practical implementation of Kerr nonlinearity in waveguides has been constrained by the material's inherently low third-order nonlinear coefficients. Here, we present a significant advancement by demonstrating Pockels effect-induced strong effective Kerr nonlinearity in a periodically poled thin-film lithium niobate waveguide. Both effective four-wave mixing (FWM) and cascaded effective FWM processes are experimentally observed. The induced FWM process achieves a maximum output power of -8.5 dBm, spanning a wavelength spectrum of over 116.8 nm. Analysis reveals that the induced effective Kerr nonlinearity exhibits a substantial effective nonlinear refractive index n(2,)(eff) more than 2.9 & times; 10(-15) m(2)/W, corresponding to an effective nonlinear refractive index enhancement factor of 1.6 & times; 10(4) relative to the intrinsic value. Moreover, a wavelength-converting experiment demonstrates a flat optic-to-optic response over a broadband radio frequency spectrum, confirming that signal integrity is well preserved after on-chip effective FWM conversion. Therefore, the demonstrated efficient and broadband Pockels effect-induced effective Kerr nonlinearity paves the way for novel applications in diverse fields, including spectroscopy, parametric amplification, quantum correlation studies, and wavelength conversion technologies.

In this paper, a hybrid intelligent optimization method based on multi-objective enhanced particle swarm optimization-genetic algorithm (MOEPSO-GA) is proposed for solving multi-objective dynamic optimization problem. This method innovatively combines the global search capability of heuristic algorithms with the high precision and guaranteed optimality of deterministic algorithms, ensuring an evenly distributed Pareto front. Firstly, a global dual optimal selection mechanism is introduced, utilizing a genetic algorithm to balance the diversity and convergence of non-dominated solutions. Secondly, an adaptive flight parameter adjustment mechanism is designed to assist particles in adaptively selecting learning modes, thereby balancing the global exploration and local development capabilities. Thirdly, the optimal replacement mechanism significantly enhances population diversity, enabling MOEPSO-GA to rapidly explore non-dominated regions. Fourthly, the adaptive epsilon -constraint method is combined with sequential quadratic programming to optimize the non-dominated set explored by MOEPSO-GA, promoting rapid convergence to the true Pareto front and thereby reducing computational costs. Finally, the effectiveness and superiority of the proposed algorithm are validated through numerical simulations and comparisons with state-of-the-art algorithms.

On-chip tunable optical delay lines are key building blocks for various applications such as microwave photonics, beamforming networks, and reconfigurable signal processing, where fast switching speed, high delay resolution, and high scalability are simultaneously required. In this work, we propose and demonstrate an ultrafast tunable lithium tantalate photonic waveguide delay line, leveraging the low propagation loss, weak birefringence, and reduced DC drift for electro-optic operation. The chip is developed with the cascade of high-speed electro-optic Mach-Zehnder switches with binary-weighted spiral delay lines. In particular, a post-fabrication phase trimming scheme based on direct laser writing (DLW) is implemented using Sb2Se3-integrated waveguide sections, providing a linear and deterministic phase correction, so that all the Mach-Zehnder switches work bias-free in their OFF state. The present on-chip system achieves a continuous delay tuning range from 0 to 1023 ps with 1 ps resolution. Finally, the system-level measurement shows excellent agreement with the theoretical prediction, validating a scalable and robust bias-free operation for the true-time delay chip.

In the era of big data and artificial intelligence, the explosive growth of data capacity has driven unprecedented demands for high-capacity and high-speed optical communication systems. The traditional single-mode and single-wavelength transmission technologies can no longer meet the requirements of massive data transmission, thereby continuously driving the industry to explore more efficient multiplexing schemes. Here, a hybrid 6-mode & times; 6wavelength division multiplexing transmitter based on lithium niobate-on-insulator (LNOI) is proposed as a groundbreaking solution for next-generation optical communication. The transmitter innovatively combines six different waveguide modes (TE0-TE5 modes) with six wavelengths spaced 3.2 nm apart, enabling the dense multiplexing of 36 independent channels within a compact optical bandwidth and achieving a capacity of 36 & times; 240 Gbps. The 3.2 nm channel spacing (approximately 400 GHz at 1550 nm) complies with the ITU-T grid standards, ensuring compatibility with existing optical network infrastructures. Meanwhile, the mode division multiplexing component utilizes multimode waveguides to fully leverage the spatial degrees of freedom in optical transmission, thereby significantly enhancing the spectral efficiency of the system compared to traditional single-mode solutions. This hybrid mode/wavelength division multiplexing architecture exhibits excellent applicability in next-generation data center interconnections and long-haul optical transmission networks.

The polarization beam splitter (PBS) is a fundamental building block for polarization handling in photonic integrated circuits. The emerging applications in sensing, imaging, and communications demand devices with ultrabroad optical bandwidth. Here, we propose and experimentally demonstrate an ultrabroadband PBS on the 340-nm silicon on insulator (SOI) platform enabled by dispersion-engineered anisotropic subwavelength-grating (SWG) metamaterials. By tailoring the pitch of SWG(<100>) structures toward the Bragg regime, the coupling-length dispersion of the PBS for TE polarization is effectively flattened. Measured results show insertion losses are < 1 dB for TE and < 0.6 dB for TM polarization, with an extinction ratio > 17.5 dB for TE and 21 dB for TM across the entire optical communication band (1.26-1.675 & micro;m).

Photonic computing promises ultrafast and energy-efficient artificial intelligence. However, existing photonic neural networks (PNNs) remain functionally shallow and difficult to scale. Here we establish a theory-guided framework showing that power stability and complex-field correlation are the fundamental prerequisites for scalable, coherent PNNs. Building on these macroscopic principles, we introduce the Coherent, Compensated and Cross-connected (C3) unit - an architecture that integrates coherent nonlinearity, active loss compensation and native optical residual connectivity. Implemented on a silicon-on-insulator platform, the C3 unit provides reconfigurable activation functions and dynamic energy stabilization without external amplification. We validate this framework using a width-constrained spiral benchmark, in which the C3 unit substantially improves parameter utilization and power robustness relative to incoherent nonlinearities. In a high-complexity 1,623-class recognition task, our C3-enabled coherent residual network (CoP-ResNet) achieves a top-1 accuracy of 77.92

The winding hot-spot temperature of power transformers is a key parameter for evaluating insulation aging and exploiting dynamic loading capability. To address the limited accuracy of conventional lumped-parameter models under dynamic loading conditions, this paper proposes a Dynamic Temperature Correction (DTC) model considering the temperature-dependent viscosity of insulating oil. By introducing real-time nonlinear correction factors, the proposed model dynamically corrects the oil time constant and winding time constant. Meanwhile, a 110 kV distributed optical fiber transformer was developed, and multi-condition temperature-rise tests were carried out. Short-circuit temperature-rise data under three different load rates and axial winding temperature distribution data under an 11-stage continuously varying load condition were obtained, revealing the winding hot-spot distribution and temperature evolution characteristics under different dynamic loading conditions. Based on the measured hot-spot temperature data from the distributed optical fiber transformer and the measured top-oil temperature data from an in-service 110 kV transformer, the calculation accuracy of the DTC model for hot-spot temperature and top-oil temperature was evaluated. The results show that the root mean square errors of the DTC model for hot-spot temperature and top-oil temperature are 1.71°C and 1.31°C, respectively, which are reduced by 22% and 46% compared with the IEC model. The experimental results indicate that the proposed DTC model can improve the calculation accuracy of transformer top-oil temperature and hot-spot temperature and has good potential for engineering application.

High-performance signal switching and routing is one key technology in the deployment of artificial intelligence and cloud computing. As more and more data are carried in the optical domain, integrated optical circuit switches provide an unprecedented solution for direct routing of optical signals, and therefore, reduce the power consumption and latency of the interconnect system. Here, an integrated micro-electro-mechanical-system optical switch is introduced, for the first time, to our knowledge, on the emerging x-cut thin-film lithium niobate (TFLN) platform. The device consists of a movable directional coupler actuated by piezoelectric cantilevers made monolithically on TFLN. The device facilitates to achieve a linear and bidirectional switching action. A coplanar electrode structure with a proper on-chip orientation is proposed and designed for utilizing the highest piezoelectric coefficient of the lithium niobate material, which also ensures compatible fabrication processes with other photonic components made on the same platform. The fabricated switch device exhibits an insertion loss of 0.8 dB and switching extinction ratios of >35 dB. A tuning rate of 2.92 dB/V for the extinction ratio is achieved under a differential drive, making it possible to drive the proposed switch with a voltage swing of a few volts. A switching time of <40 mu s is also measured. High-speed data transmission and switching are also demonstrated, showing the broadband operation of the present device. (c) 2026 Chinese Laser Press

High-speed and energy-efficient scalable photonic switches are essential for next-generation optical interconnects and computing. However, existing techniques suffer from random fabrication variations, complicated calibration mechanisms, and limited switching speeds, which collectively hinder large-scale integration and high-robustness systems. Here, we present a monolithic 4 × 4 programmable optical matrix based on microring resonators (MRRs) integrated on a thin-film lead zirconate titanate (PZT) platform. We achieve non-volatile resonance wavelength alignment with sub-50 pm precision in the tuning range exceeding a full free-spectral-range (FSR) for all MRRs. The PZT MRRs simultaneously exhibit ultrafast electro-optic switching with a rising/falling time of 45/37 ps, respectively, along with negligible DC (direct current) drift (< 0.04 nm). When configured as an optical switch, the present optical matrix achieves a minimum excess loss of 0.75 dB and maximum crosstalk suppression of 43.2 dB. The optical matrix can also be configured as a wavelength-selective switch (WSS) with a maximum extinction ratio of 39 dB and an optical transmitter enabling high bit rates of 40 Gbps per channel. Furthermore, a reconfigurable optical weight matrix for non-volatile in-memory multiply-accumulate (MAC) computations is also demonstrated, potentially achieving 96.98

Micro-electromechanical system (MEMS) photonic switches based on adiabatic directional couplers (ADCs) potentially offer the advantages including large fabrication tolerance and broad bandwidth, which is essential for large-scale reconfigurable photonic integrated circuits in optical networks and artificial intelligence computing infrastructures. However, the scalability of previous ADC-based MEMS switches is challenging due to the complicated fabrication of vertical ADC switches and buckling-induced performance deterioration of horizontal ADC switches. Here we propose a mechano-optically co-designed 2×2 MEMS switch based on a unique buckling-free horizontal ADC by introducing residual-strain management structures including slab anchors and extra S-bends. For the fabricated device, the waveguide buckling is alleviated significantly and high optical performance is achieved with low loss and low crosstalk over a broad bandwidth of 180 nm. It also features fast switching speed of ~ 2 µs, reliable durability with > 7.2 billion switching cycles, and exceptional scalability with the realization of a 64×64 Benes switch array. The present 2×2 horizontal ADC switches are compatible with all mainstream array topologies and can be fabricated using simple standard silicon photonic foundry processes, which are not accessible for those 1×2 ADC switches reported previously. With these advantages, the present design provides a highly-scalable solution with great potential for MEMS/NEMS photonic devices used in versatile applications.

Abstract Supercontinuum generation makes use of the nonlinear optical effects arising from the interaction of light with the bound electronic states in crystal lattices and has many applications, especially in the ultraviolet for the direct probing of large-energy electronic transitions. However, supercontinuum from integrated waveguides has been limited to >330 nm in the ultraviolet-A band because of material dispersion and absorption. Here, we demonstrate unprecedented ultraviolet-C-to-mid-infrared supercontinuum on a chip, leveraging the exceptional transparency window and second-order nonlinearity of lithium tantalate (LT). A key innovation is the introduction of chirped periodically poled LT with submicron ferroelectric domains. Utilizing 3-wave-mixing processes under quasi-phase-matching conditions, we created the shortest ultraviolet wavelength ever reported from a chip—below 270 nm—while reaching 2400 nm in the mid-infrared, covering more than three octaves with just 100 pJ pulse energy on a chip for the first time. It’s the first on-chip supercontinuum fully covering the ultraviolet-A/B bands while extending into the ultraviolet-C band. This work establishes thin-film LT as a versatile platform for full-spectrum nonlinear photonics, opening new possibilities for integrated ultraviolet sources.

On-chip photonic computing shows promise for tasks such as neural networks due to its parallelism and low latency. However, the impact of the nonlinear transfer curve of photonic modulators on the accuracy of photonic computing is underexplored. Current systems rely on digital post-processing, limiting energy efficiency. To address this, we propose a direct-drive and direct-detection (D4) architecture with precision-alignment design, simplifying the photonic-electronic interface. We develop a theoretical model to analyze precision constraints from modulation nonlinearity in MRRs and MZIs. Our analysis shows that both devices offer about 7 effective number of bits (ENOBs), limited by detector shot noise. This indicates that achieving high precision (e.g., 8-16 bits) for analog photonic computing faces fundamental limitations under current assumptions. This study highlights key challenges for future development.

Features such as an ultra-large free spectral range (FSR) even FSR-free operation, as well as large range tunability, can significantly expand the application of optical filters. However, simultaneously achieving these characteristics remains challenging for existing schemes due to device footprint or complexity limitations. In this work, we propose and demonstrate a novel filter that overcomes this limitation by employing a phase-change-material (PCM)-assisted multimode Bragg grating (MBG) to selectively filter the resonance peaks of an add-drop microring, thereby realizing an FSR-free, narrowband, reconfigurable filter. The fabricated device exhibits a side-mode suppression ratio greater than 15.52 dB and an insertion loss below 2.5 dB over the 1500–1580 nm wavelength range. By combining laser-induced phase change for the MBG together with the thermo-optic tuning of the microring, wide, continuous tuning with range exceeding 30 nm has been demonstrated while maintaining the FSR-free operation.

Abstract Photonic integrated circuits (PICs) are essential for modern optoelectronics, yet fabrication-induced random phase errors often necessitate precise detection and calibration before application. Optical probing offers a direct detection method before packaging. However, conventional probes suffer from large footprints and significant inherent loss. In this work, we propose and demonstrate an ultracompact, erasable optical probe based on a phase-change-material (PCM)-assisted directional coupler. The device features a footprint of less than 14 × 6 μm2. In the ON state, the probe extracts approximately 6% of the optical power for monitoring, while in the OFF state, it exhibits a negligible residual loss of less than 0.02 dB. The probe leverages reversible phase transitions to switch between the two states. We further validate its performance by implementing in situ monitoring within a 4 × 4 optical switch array. This PCM-assisted probe provides a scalable and efficient solution for large-scale PICs.

Dense wavelength division multiplexing (DWDM) is regarded as a revolutionary solution that significantly enhances transmission capacity. However, DWDM in electro-optic (EO) material platforms faces bottlenecks including limited channel numbers, large insertion losses (ILs), and limited spectral efficiency. Here, an 8×240 Gbps DWDM transmitter at O band is demonstrated on a lithium-tantalate-on-insulator platform through proposing a robust flat-top optical filter based on a novel coupled Fabry-Perot (FP) cavity. The flat-top optical filter shows overall high performance of a low IL of ~0.1-0.4 dB, a large free spectral range of 12 nm, a high extinction ratio (ER) of ~26 dB, and a large fabrication tolerance. The 8-channel DWDM transmitter is further realized with uniform channel spacings of 200 GHz and a total data capacity of 8×240 Gbps. Therefore, it offers a critical strategy for enhancing the capacity of optical links, holding significant promise for widespread application in fields like data centers and artificial intelligence.

In this paper, we propose and demonstrate an integrated polarization-insensitive single-mode filter (SMF) on a 340 nm silicon-on-insulator (SOI) platform, by introducing two lateral coupling waveguides to couple high-order modes from central single-mode waveguide to lateral waveguides. The experimental results show that the excess loss is <0.29 dB and the extinction ratio is >20 dB with a broad bandwidth of 136 nm for the fabricated SMF with a compact footprint of <13 µm.

The rapid development of artificial intelligence has catalyzed substantial progress in photonic information processing, which requires ultralow-power photonic switches for extensive circuit reconfiguration. Nonvolatile switches with zero static power are promising, but current phase change material approaches face challenges including unreliable durability, high switching energy, complicated fabrication, and compromised scalability. Here, we propose and demonstrate a nonvolatile silicon photonic microelectromechanical system (MEMS) switch enabled by tailored stiction effect based on van der Waals (vdW) force. The device uses a unique split waveguide crossing (SWX) with a push-pull MEMS actuator to efficiently switch the mode propagation. The vdW force between two halves of the combined SWX with zero gap provides reliable nonvolatility. The device features 0.23-decibel excess loss, 44.4-decibel extinction ratio, 200-nanometer bandwidth, and ~1-picojoule theoretical switching energy. Furthermore, excellent scalability is validated by a fabricated high-performance 16 by 16 nonvolatile photonic switch array, which has never been reported before.

Highly efficient acousto-optic modulation plays a vital role in microwave-to-optical conversion. Herein, a hybrid thin-film lithium niobate (TFLN) racetrack micro-ring acousto-optic modulator (AOM) implemented with a low-loss chalcogenide (ChG) waveguide is demonstrated. By engineering the electrode configuration of the interdigital transducer, the double-arm micro-ring acousto-optic modulation is experimentally confirmed in a non-suspended ChG-loaded TFLN waveguide platform. Varying the position of the blue-detuned bias point, the half-wave-voltage-length product V pi L of the hybrid TFLN micro-ring AOM is as small as 9 mV cm. Accordingly, the acousto-optic coupling strength is estimated to be 0.48 Hz s1/2 at an acoustic frequency of 0.84 GHz. By analyzing the generation of sideband photon number coupled out of the cavity, the ratio between the microwave photons and first-order optical sideband photons is calculated to be 2.2 x 10-7% at room temperature. Highly efficient micro-ring acousto-optic modulation thus provides new opportunities for expanding TFLN-ChG hybrid piezo-optomechanical devices applied in the low-power-consumption quantum information transduction.

Optical memristors represent a monumental leap in the fusion of photonics and electronics for neuromorphic computing and artificial intelligence. Here, we reveal the first lead zirconate titanate (PZT) optical memristor, working with a paradigm of functional duality: non-volatile setting and ultrafast volatile modulation via the Pockels effect. Fine-tuning and large modulation depth are achieved with an index change of 4.6 × 10-3 when setting above a threshold voltage Vth and the switching energy is 12.3 pJ only. The non-volatility is highly stable even with >100,000 cycles. Sub-nanosecond volatile modulation (48 Gbps, 432 fJ/bit) is realized with high efficiency (VπL ~ 0.5 V·cm) via the strong Pockels effect below Vth. Our wafer-scale manufacturing process shows great potential for mass production. The present PZT optical memristors bridge the gap between high-speed photonics and non-volatile memory, offering transformative potential for high-speed and energy-efficient optical interconnects, quantum computing, neural networks, in-memory computing, and brain-like architecture.