Silicon is a promising anode material for high-energy-density Li-ion batteries due to its high theoretical capacity (~4200 mAh·g−1). However, its practical application is hindered by severe volume expansion and interfacial instability. Constructing silicon-carbon (Si/C) composites is effective, but conventional methods rely on high-purity Si and costly carbon precursors. Here, we propose a sustainable strategy using cross-linked ethylene-vinyl acetate (EVA) and crystalline silicon recovered from waste photovoltaic modules. Waste EVA was pyrolyzed into a porous, defect-rich carbon skeleton and combined with recovered silicon via ball-milling and carbonization to form an EVA-derived carbon-coated silicon composite (E-C/Si1). The carbon layer uniformly coats Si particles, suppressing oxidation and enhancing stability. Electrochemical tests show an initial discharge capacity of 763 mAh·g−1 at 0.1 A g−1 with an initial Coulombic efficiency of 81.7%, stable cycling over 200 cycles, and good rate capability. Compared to commercial graphite/silicon anodes, E-C/Si1 offers comparable capacity with superior cycling stability and charge-transfer kinetics. This work provides a new route for valorizing photovoltaic waste and a green strategy for low-cost, high-performance Si/C anodes.

To mitigate integration risks in sensing systems and fill the technological gap in anomaly detection for fiber optic sensors, this study develops a formic acid (FA) gas sensor that is resistant to humidity interference at room temperature and introduces a potential anomaly detection method. The sensor is based on a single-mode-no-core-single-mode (SNS) structure and achieves a bilayer coating of molybdenum disulfide nanosheets (MoS2 NS) and polydimethylsiloxane (PDMS) via a dip-coating method. Under room temperature conditions, it demonstrates a detection sensitivity of similar to 0.78 pm/ppm for FA gas, with a detection limit of 10 ppm, and exhibits exceptional selectivity and resistance to humidity interference. The sensor not only shows promise for dual-parameter detection of FA gas and temperature but also holds significant potential for anomaly detection. The anomaly detection method presented in this study is based on a dual-parameter detection principle and introduces an implementation mechanism that leverages the two-dimensional characteristics of the fiber optic spectrum. Its principle is simple and easy to apply, offering potential for further research and application in the field of sensors utilizing two-dimensional and higher-dimensional signals. We believe this achievement will not only drive the development of anomaly detection technology for fiber optic sensors but also contribute to the multi-functional integration and system enhancement of industrial and smart city systems.

In this work, we first present a miniaturized fiber optic gyroscope (FOG) transceiver based on an ultra-low loss silicon nitride (SiN) photonic chip operating at O-band. The photonic chip serves as a power splitter and polarizer, featuring high-efficiency edge couplers for hybrid integration with an external broadband light source and a high-performance photodetector (PD). The transceiver is co-assembled based on a standard butterfly package with a thermo-electric cooler (TEC). At a driving current of 100 mA, the transceiver produces an output power of 1.36 mW, which increases to 4.25 mW at 200 mA. Built with a fiber coil with similar to 380 m length and similar to 60 mm average diameter, the preliminary transceiver-based FOG exhibits the 10 s Allan deviation of 0.0969 degrees/h and the angular random walk (ARW) of 0.0058 degrees/root h, which is comparable with their discrete counterparts. By integrating the high-power integration advantages of the SiN photonic platform with a reduction in fiber splices, this approach lays a solid foundation for developing more compact, high-precision, and high-power-required fiber-optic sensing systems.

The compact fiber structural temperature sensors have been proposed and prepared through inserting one cut of single-mode fiber (SMF) or hollow-core fiber (HCF) between two convex-cone structures, which were fabricated by the arc discharging process in a common fiber splicer, and served as the splitting and interfering joint of the Mach-Zehnder interferometer. The temperature sensing performance for the two proposed SMF- or HCF-based double convex-cones structures have been experimentally demonstrated with the sensitivities of -0.072 nm/degrees C and 0.162 nm/degrees C, respectively. In comparison, the SMF-based double convex-cones structure performs a better stability in the interference spectrum; while the HCF-based double convex-cones structure has a higher sensitivity. To further improve the sensing performance of the HCF-based temperature sensor, the splicing quality at the interface between HCF and convex-cones should be optimized to eliminate the air tube deformation and reduce the splicing loss. The sensitive materials can be filling into the air core of HCF to improve the sensitivity. The proposed temperature sensors are easy to fabricated without using expensive special fibers or complex micro-machining process. Same to the common optical fiber sensors, this compact structure with input and output SMFs is easy to install and integrate into different devices and systems, suitable for harsh environments with high electromagnetic interference, high humidity, and limited space.

Fabry-Perot interferometer (FPI) microcavity humidity sensor based on chitosan encapsulated hollow core fiber. The sensor's humidity response characteristics have been experimentally demonstrated with the average humidity sensitivity of 0.846 nm/%RH within the humidity range of 35 % similar to 65 % RH, with sub-range average sensitivity of 0.956 nm/%RH specifically in the 41 % similar to 65 % RH interval. The chitosan-FPI based optical fiber humidity sensor offers the advantages of the simplified fabrication processes, compact structural configuration, cost-effectiveness, high sensitivity, and superior humidity response performance. These attributes indicate its substantial application prospects in the development of wearable biosensing systems, particularly for real-time humidity monitoring applications.

The development of rapid, sensitive ammonia (NH3) sensors is crucial for emergency response as NH3 poses serious health risks. We report a high-performance chemiresistive sensor based on Ti3C2 MXene@sulfur nanosheet (MXene@S-NSs) composites that addresses the conductivity limitations of pure S-NSs. The composite combines MXene's excellent conductivity with S-NSs' semiconductor properties to create room-temperature NH3 sensors with exceptional performance: 3 ppt detection limit, 375 % response signal, and remarkably fast response/recovery times of 5 s/4s - representing a significant improvement over pure S-NSs sensors. This enhancement arises from optimized charge transport through p-n heterojunctions and sulfur vacancies in the composite structure. The MXene@S-NSs material demonstrates outstanding sensitivity, stability, and response speed, making it particularly suitable for emergency NH3 monitoring applications. This work not only presents a practical sensor solution but also establishes an effective materials design strategy for developing next-generation gas sensors through rational 2D material hybridization. The successful integration of MXene and S-NSs provides a blueprint for creating advanced sensing materials with tailored electronic properties and performance characteristics.

Leveraging the advantages of Fabry-Perot interferometer (FPI) fiber sensors and chitosan humidity-sensitive materials, this study proposes and validates a high-performance humidity-sensitive fiber probe. Structural parameters of the chitosan-coated FPI fiber sensor were experimentally optimized, demonstrating that a hollow-core fiber (HCF) length of 104 μm and chitosan film thickness of 7 μm achieve a sensitivity of 0.6198 nm/%RH during 20%-70% RH. The maximum humidity sensitivity of 1.0132 nm/%RH was observed in the subrange of 45%-70% RH. The sensor exhibits rapid humidity response time of 547 ms and recovery time of 578 ms, enabling real-time environmental humidity monitoring. Its potential for human motion tracking was verified through respiratory experiments at varying frequencies. To address Internet of Things (IoT) requirements for simultaneous environmental monitoring, an integrated dual-parameter sensor was designed using cascaded temperature-humidity sensing units and a decoupling algorithm, achieving concurrent temperature-humidity detection.

This paper proposed a cascaded fiber structure comprising single mode-hollow core-single mode convex-taper fibers (SHSC), where the air column of the hollow-core fiber (HCF) is filled by the temperature-sensitive material to achieve the dual-parameter sensing of temperature and refractive index (RI). An experimental system for temperature and RI sensing was designed and constructed, and corresponding sensing experiments were conducted. In the RI sensing experiments, sodium chloride (NaCl) solutions with different concentrations were utilized to verify the RI sensing performance. In the temperature sensing experiments, a constant-temperature heater was employed to adjust the environmental temperature and explore the temperature sensing characteristics. Variations in temperature and RI were obtained by monitoring the Fabry-Perot reflection spectrum and the Mach-Zehnder transmission spectrum, respectively. Experimental results demonstrate that the cascaded fiber structure SHSC enables the dual-parameter sensing of temperature and RI, achieving sensitivities of 1931.1 pm/ degrees C and -5.63 dBm/RIU, respectively. The proposed fiber optic sensing probe, characterized by its compact structure, has the promising potential for simultaneous measurement of temperature and RI. It can be integrated into fiber optic communication systems, offering high-precision real-time monitoring capabilities for biochemical substances.

To address the miniaturization requirements of fiber optic gyroscope (FOG) modules, in this work, we propose an optoelectronic architecture based on hybrid integration and packaging. By co-packaging the transimpedance amplifier (TIA) circuit with silicon photonic FOG chip in an industry-standard 14-pin butterfly package. The module comprises three key subsystems: optics, electronics, and thermal management. The multifunctional optical subsystem is composed of a hybrid integrated chip which functions simultaneously as a light source, polarizer, power splitter, as well as photodetector. The electronic subsystem acts as a pre-amplifier by integrating a low-noise TIA circuit with customizable transimpedance. Thermal management combines thermoelectric coolers (TECs) and negative temperature coefficient (NTC) sensors.The FOG test shows the 10 s smooth bias stability is 0.0995 degrees/h. The results are slightly better than the FOG with discrete counterpart. Our work provides a scalable solution for high-precision inertial navigation systems, demonstrating significant potential for cost-effective mass production in aerospace, autonomous vehicles, and industrial robotics applications.

In this work, we present a novel silicon photonics multi-function fiber optic gyroscope (FOG) engine, which is composed of a broadband optical source, an on-chip germanium (Ge) photodetector (PD), a carrier-depletion silicon modulator, polarization maintaining splitters, polarizers, as well as high-efficiency edge couplers. The engine is co-assembled with a thermo-electric cooler (TEC) in a standard butterfly package with an overall size of 22 mmx12.6 mmx8.1 mm. The experimental results exhibit obvious gyroscope effects. The extracted scale factor and linearity is 3.8739 mu V/(deg/hr) and <= 0.3%, respectively. Leveraged with CMOS compatible silicon photonics platform and largely reduced fiber fusion splicing points, the presented silicon photonics multi-function FOG engine provides a promising solution toward a novel FOG system with low cost, high production efficiency, high integration density, strong stability, and mass production possibility, which is thus useful for miniaturized FOG sensors research and development.

In this work, we present a high-power O-band fiber optic gyroscope (FOG) transceiver module based on a silicon nitride (SiN) photonic chip. The transceiver integrates a broadband super-luminescent diode (SLD) source, a high-performance photodetector (PD), and a SiN photonic chip with beam-splitting and polarization functionality. The entire transceiver module is co-assembled with a thermoelectric cooler (TEC) and a negative temperature coefficient (NTC) thermistor in a commercially standard 8-pin butterfly package with dimensions of 22 mm x 12.6 mm x 8.1 mm. The transceiver exhibits high output power of 1.36 mW at 100 mA driving current, and 4.25 mW at 200 mA, such high-power operation is feasible for the sensing applications where high optical power is required. The open-loop test exhibits distinct gyroscope effects, and the transceiver-based closed-loop FOG test demonstrates a precision of 0.11 degrees/h for 10 s smooth bias stability at room temperature. The high-power integrated FOG based on the SiN photonic platform reduces fiber splicing points and minimizes size, paving the way for cost-effective, compact, high-precision, and high-power-required fiber optic sensing applications.

As the demand for high-performance, miniaturized, and low-power devices continues to rise in integrated inertial navigation systems, chip-scale optical gyroscopes have become a central focus for the next generation of navigation sensors. This paper presents an innovative photonic engine chip based on heterogeneous integration technology, successfully implemented in an interferometric optical gyroscope (IFOG) system. The chip achieves high integration of key components-including the light source, coupler, modulator, polarization beam splitter, and photodetector-by combining silicon nitride (SiN) and thin-film lithium niobate (TFLN) materials through heterogeneous integration. This approach effectively overcomes the performance limitations inherent in traditional single-material platforms. The chip measures just 2.2 mm & times; 10 mm and, after system-level packaging, is seamlessly integrated into the gyroscope system. Experimental results demonstrate that the proposed system achieves a bias stability of 0.38 degrees/h, significantly outperforming previously reported comparable technologies and highlighting its strong potential for high-precision inertial sensing applications. This technology not only effectively reduces system size and power consumption but also provides excellent compatibility with CMOS processes and scalability, meeting the rigorous integration and stability requirements of high-precision optical inertial navigation systems. Furthermore, it showcases the feasibility of heterogeneous photonic integration technology in the realm of high-precision inertial sensors, establishing a strong foundation for the realization of true chip-level navigation systems.

Exceptional points (EPs) promise revolutionary control over quantum light-matter interactions. Here, we experimentally demonstrate flexible and reversible engineering of quantum vacuum fluctuation in an integrated microcavity supporting chiral Eps. We develop a hybrid lithium niobate (LN)-GaAs quantum photonic platform, seamlessly combining high-quality quantum emitters, a low-loss photonic circuit, efficient electro-optic (EO) effect, and local strain actuator in a single device. Chiral EPs are implemented by dynamically tuning the coupling between the modes associated with a micro-ring resonator, resulting in anomalous spontaneous emission dynamic with a 7-fold modulation of the lifetime (120 ps to 850 ps). Meanwhile, we reshape single-photon spectra via cavity local density of states (LDOS) engineering and generate non-Lorentzian spectral profiles: squared-Lorentzian, Fano-like, and EP-induced transparency (EPIT), a suppression of emission at zero detuning. This work unveils exotic cavity quantum electrodynamics (cQED) effects unique to EPs and establishes a universal paradigm for non-Hermitian quantum photonics.

This study presents a humidity sensor based on a large-core-offset hollow core optical fiber (LD-HCF) combined with polyvinyl alcohol carbon quantum dots (PVA-CQDs) nanocomposite microfiber for monitoring human respiratory. PVA-CQDs was introduced into the hollow core structure of LD-HCF to develope the respiratory sensor. The sensor has been integrated into a respiratory monitoring mask, exposed to ultraviolet (UV) light and demonstrated with a humidity sensitivity of 0.1721nm/%RH as well as response and recovery times of 0.232s and 0.252s, respectively. The mask provides the real-time monitoring of human respiratory rates during various activities, including walking, standing, coughing, running, apnea 1 time and apnea 3 times. The typical respiratory patterns have been classified with a remarkable accuracy of 97.62% using a WOA-1D CNN-LSTM neural network. The respiratory monitoring device is proposed by optical fiber, offering a promising potential in the real-time monitoring for healthcare process.

In this study, we propose an optical fiber sensor by cascaded-integrating a silicone oil encapsulated hollow-core photonic crystal fiber (HC-PCF) with a silica membrane for the simultaneous measurement of temperature and pressure. The temperature variation induces a refractive index change of the silicone oil filled in the external environment of HC-PCF, leading to its spectral variations and enabling the temperature measurement. The deformation of the silica membrane under pressure results in a dynamic change in the optical path length, thereby causing the variations in the interference pattern. Experimental results demonstrate a temperature sensitivity of 0.083 nm/degrees C, with an error of only 0.048 degrees C caused by spectral drifting. Additionally, the pressure sensitivity is determined to be 0.409 nm/MPa. The cross-sensitivity between temperature and pressure measurements is eliminated by establishing a sensing matrix, to enable the synchronous measurement of both parameters. The proposed sensor exhibits the compact structure, high sensitivity, and excellent repeatability, providing theoretical and technical references for the development of dual-parameter optical fiber sensors.

To improve the issues of interference resistance and selectivity, as well as the challenge of multiparameter detection using single sensors in the field of sensor technology, this study develops a potential multifunctional optical fiber sensor and a multiparameter fusion detection method. During the sensor fabrication process, the two-dimensional detection mechanism of the single mode-no-core-single mode (SNS) optical fiber structure was demonstrated through optical principles and simulation analysis. In addition, improvements were made to the preparation method of molybdenum disulfide nanosheets (MoS2 NS) and the dip-coating method for the transmissive optical fiber structure. These modifications enhanced the sensor’s sensitivity to formic acid (FA) gas by ∼5 times and reduced the detection limit to 2/5 of that of its predecessor. The proposed method enables the fusion detection of target and interference parameters, and its effectiveness has been validated through experiments. The introduction of this method will not only help address the issues of interference resistance and selectivity in sensors but also contribute to the advancement of sensor integration technology.

This study presents a three-axis interferometric fiber optic gyro (TA-IFOG) that utilizes a silicon-based multi-channel integrated detector chip(MC-IDC) to enhance the system's performance and compactness. Advanced optical integration techniques enable the incorporation of couplers, polarization beam splitters, and photodetectors onto a single chip, thereby further streamlining the design. The test results indicate that the MC-IDC performs excellently. The power distribution across each channel is uniform, with an extinction ratio of 20 dB and a loss of approximately 18 dB. The chip's photoelectric conversion efficiency surpasses 0.9 A/W, and it maintains a dark current below 3.4 nA. Furthermore, testing of the TA-IFOG system confirms that its accuracy is better than 0.18°/h under normal temperature conditions. In comparison with traditional three-axis fiber optic gyros, the TA-IFOG system offers a simplified design that significantly reduces both cost and size, thereby increasing its potential for broader market adoption.

Fluorescence super-resolution microscopy has enabled nanoscale imaging of intracellular structures, but it remains challenging to simultaneously achieve structural imaging and quantitative functional characterization, such as pH measurement, within the same region. Here, we introduce two-color single-molecule blinking ratiometricity (2C-SMBR), a novel method that integrates structural and functional imaging with single-molecule precision. By loading lysosomes with two pH-dependent spontaneously blinking fluorophores of distinct colors, 2C-SMBR leverages single-molecule localization of either fluorophore to achieve nanoscale structural imaging of lysosomes, whereas the ratiometric analysis of blinking dynamics between the two fluorophores provides quantitative pH measurement at the single-lysosome level. This dual-color ratiometric approach at the single-molecule level enables precise quantification of lysosomal pH with exceptional spatiotemporal resolution. Using 2C-SMBR, we reveal that lysosomal pH is highly heterogeneous at the single-lysosome level, with distinct subpopulations exhibiting diverse pH values. Our measurements show a pH range of 4.0-6.0 within lysosomes, with perinuclear lysosomes averaging a pH of approximately 4.88, whereas peripheral lysosomes average around 5.64. Crucially, 2C-SMBR enables real-time correlation between lysosomal dynamics and pH changes, overcoming a key limitation of super-resolution imaging. This approach not only advances nanoscale organelle characterization but also provides mechanistic insights into lysosomal physiology and function.

An optical fiber triethylamine (TEA) gas sensor based on a hollow malposition structure (HMS) platform with CQDs@BiOBr gas-sensing layer is proposed. The CQDs@BiOBr gas-sensing material is coated onto the surface of the hollow core fiber (HCF) using a dip-coating method. The misaligned structure is designed to guide light transmission within the cladding of the HCF and excite the evanescent field. The heterojunction formed between CQDs and BiOBr enhances the separation efficiency of electron-hole pairs, improving the transfer speed of charge carriers during the gas adsorption process. Experimental results show that the sensitivity of sensor at room temperature is 3.53 pm/ppm, which is 2.43 times higher compared to a sensor coated with BiOBr alone. Additionally, the response and recovery times of sensor are 12 s and 36 s, respectively, with a limit of detection (LOD) of 5.67 ppm. DFT calculations provide insight into the electronic transfer pathways and electron cloud distribution during the gas adsorption process, further validating the crucial role of the CQDs@BiOBr heterojunction in enhancing gas-sensing performance. The proposed optical fiber TEA gas sensor shows significant potential for applications in environmental monitoring and industrial safety.