Sensor Structure Research Articles

Design and analysis of D-shaped fiber optic plasmonic sensors using triangular corrugation of silver: transmittance and field analysis

In this study, the wave optics module of COMSOL Multiphysics is used to simulate a D-shaped optical fibre plasmonic sensor with triangular corrugation structures made of silver. The transmittance and electric field-based performance defining parameters i.e., resonance wavelength (λ r), shift in resonance wavelength (∆λ r), minimum transmittance (Tmin), bandwidth (BW), penetration depth (PD), and propagation length (PL) are examined. The obtained sensitivity of the proposed sensor is 10.2 μm RIU−1. It is seen that the proposed sensor structure increases the sensitivity by 41% with respect to planar Ag and 40.2% with respect to rectangular grating of Ag. Also, the PD increases 36.6% with respect to planar Ag and 30% with respect to rectangular grating Ag.

Stretchable Piezoresistive Pressure Sensor Array with Sophisticated Sensitivity, Strain-Insensitivity, and Reproducibility.

This study delves into the development of a novel 10 by 10 sensor array featuring 100 pressure sensor pixels, achieving remarkable sensitivity up to 888.79kPa-1, through the innovative design of sensor structure. The critical challenge of strain sensitivity inherent is addressed in stretchable piezoresistive pressure sensors, a domain that has seen significant interest due to their potential for practical applications. This approach involves synthesizing and electrospinning polybutadiene-urethane (PBU), a reversible cross-linking polymer, subsequently coated with MXene nanosheets to create a conductive fabric. This fabrication technique strategically enhances sensor sensitivity by minimizing initial current values and incorporating semi-cylindrical electrodes with Ag nanowires (AgNWs) selectively coated for optimal conductivity. The application of a pre-strain method to electrode construction ensures strain immunity, preserving the sensor's electrical properties under expansion. The sensor array demonstrated remarkable sensitivity by consistently detecting even subtle airflow from an air gun in a wind sensing test, while a novel deep learning methodology significantly enhanced the long-term sensing accuracy of polymer-based stretchable mechanical sensors, marking a major advancement in sensor technology. This research presents a significant step forward in enhancing the reliability and performance of stretchable piezoresistive pressure sensors, offering a comprehensive solution to their current limitations.

Grating Structures for Silver-Based Surface Plasmon Resonance Sensors with Adjustable Excitation Angle.

Silver-based grating structures offer means for implementing low-cost, efficient grating couplers for use in surface plasmon resonance (SPR) sensors. One-dimensional grating structures with a fixed periodicity are confined to operate effectively within a single planar orientation. However, two-dimensional grating structures as well as grating structures with variable periodicity allow for the plasmon excitation angle to be seamlessly adjusted. This study demonstrates silver-based grating designs that allow for the plasmon excitation angle to be adjusted via rotation or beam position. The flexible angle adjustment opens up the possibility of developing SPR sensor designs with an expanded dynamic range and increased flexibility in sensing applications. The results demonstrate that efficient coupling into two diffraction orders is possible, which ultimately leads to an excitation angle range from 16° to 40° by rotating a single structure. The findings suggest a promising direction for the development of versatile and adaptable SPR sensing platforms with enhanced performance characteristics.

Concept, simulation, and fabrication of inverted grating structures for surface plasmon resonance sensors

Abstract. Surface plasmon resonance (SPR) sensors offer the possibility of label-free analysis of biosamples. The long-term stability of standard approaches is limited due to degradation of the grating upon contact with the analyte, and strategies to improve the performance in this regard include the use of so-called inverted configurations. By exciting surface plasmons from the back side of the grating, this design overcomes limitations of traditional grating-based SPR sensors caused by direct contact with the analyte medium and offers new design possibilities for implementing microfluidic analytical systems. Here a simulation for optimizing design parameters and a corresponding microfabrication technology to create the inverted grating are presented. An experimental evaluation of surface plasmon excitation and sensitivity enhancement demonstrates the feasibility of the approach. While the observed coupling effect of inverted grating structures is not as strong as the conventional configuration, it offers benefits like preventing surface oxidation, enabling repeated usage and new concepts for biosample processing.

Colorimetric detection of sitagliptin and moxifloxacin using AgNPs modified by 4-mercaptophenylbronic acid

Nowadays, considering the vital role of drugs, identifying and diagnosing them with simple and cost-effective methods and materials is very important. This study explores a colorimetric approach using silver nanoparticles (AgNPs) modified with 4-mercaptophenylboronic acid (MPBA) as a rapid and economical sensor for detecting Sitagliptin (Sit) and Moxifloxacin (Moxi) drugs. The MPBA-AgNPs sensor was synthesized via chemical synthesis of AgNPs followed by surface modification by MPBA. The effect of different parameters on the responsiveness of the MPBA-AgNPs sensor was investigated. The surface morphology, chemical structure, and size of the MPBA-AgNPs sensor in different conditions were examined by FE-SEM, FT-IR, DLS, and TEM analysis. Finally, the results of various investigations showed that the surface of AgNPs successfully modified by MPBA and MPBA-AgNPs as a colorimetric sensor for the detection of Sit and Moxi drugs has excellent detection limits of 16.63 and 0.27 µM. The recovery of the experiment in real samples was obtained in the range of 92.37–105.44 %.

Theoretical investigation on gas sensing characteristics of 3d transition metal atom doped C9N7 for toxic gases (CO, NO, NO2, and SO2)

This study investigates the sensing performance of a series of 3d transition metal doped C9N7 sensor structures for four toxic gases (CO, NO, NO2, and SO2). A series of sensor configurations with single and double 3d transition metal atoms doped with C9N7 (TM-C9N7 and TM2-C9N7) are constructed. The stability of the sensor configuration is evaluated by calculating the formation energy and dissolution potential. The stability analysis results indicate that except Sc-C9N7, Mn2-C9N7, and Cr2-C9N7, all sensor configurations have good structural stability. For screened sensor structures with good structural stability, the adsorption energy values of four toxic gases and three common gases (N2, O2, and CO2) are compared to evaluate their selectivity towards toxic gases. Moreover, the recovery times are also calculated to further evaluate the sensing performance. Through comprehensive evaluation, four sensor structures (Fe-C9N7, Cu-C9N7, Zn-C9N7, and Zn2-C9N7) with high selectivity and relatively short recovery time for toxic gases are determined. Among them, Fe-C9N7 is suitable for sensors of toxic gases NO2, and SO2, while Cu-C9N7, Zn-C9N7, and Zn2-C9N7 have good sensing performance for all four toxic gases.

Design and analysis of sensor structure based on ultrasonic temperature measurement

Abstract Based on the principle of ultrasonic temperature measurement, this paper designs the structure of a waveguide rod sensor with a reflective groove. Using multi-physics field simulation software to conduct acoustic thermal coupling parametric simulation analysis on six different high melting point materials, we obtain the curve functions of the relationship between sound velocity and temperature for the six materials and verify the feasibility of ultrasonic temperature measurement using waveguide rods. Analysis shows that the sensitivity of six alloys to temperature changes is as follows: Ti6Al4V titanium alloy > α-Al2O3 > Inconel693 nickel-based alloy > ThO2 > Tungsten-rhenium alloy > Ta8W2Hf. At the same time, three different shapes of waveguide rods were designed: single groove waveguide rod, multi-zone waveguide rod, and spiral waveguide rod to analyze the impact of temperature measurement accuracy. The research results have important theoretical guidance significance for solving the problem of temperature measurement in high-temperature environments.

Optimization of Optical Biosensor Based on 1D Photonic Crystals with Metaheuristic Algorithms for Measuring Glucose Concentration

We aim to simulate an optimal optical biosensor based on one-dimensional crystal photonics, for measuring blood and urine glucose concentration. By optimizing the sensor structure through metaheuristic optimization algorithms, sensitivity was increased. To measure blood and urine glucose concentration, these materials are used as a defect layer in one-dimensional crystal photonics, consisting of three materials: magnesium fluoride (MgF2), borosilicate glass (BK7), and orphan iodide (LiI) with refractive indices of 37/1, 1/5, and 1/99. By changing the concentration of glucose, the refractive index of the defect layer changes, changing the optical properties of the defect layer in the photonic crystal and the spectrum of transmitted and reflected light. According to the amount of light absorption by glucose, a wavelength range of 900–2200 nm (near infrared) was used as the input light. The transfer matrix method was used to calculate multi-layer systems. This method is based on the definition of two matrices, the boundary matrix and the diffusion matrix, which can be used to directly apply the boundary conditions. By plotting the spectrum passing through the crystal using the transfer matrix method and determining the location of the peak in the spectrum, the sensitivity of the sensor was calculated for different concentrations of glucose in blood and urine. The sensitivity obtained before optimization was 530 nm RIU−1, while after optimization it reached 842 nm RIU−1.

Gold nanowire-infused square-clad SPR-PCF biosensor for detection of various cancer cells

This research work introduces a Surface Plasmon Resonance (SPR) based Photonic Crystal Fiber (PCF) sensor using gold nanowires as plasmonic material designed for the detection of various cancer cells, boasting remarkable sensitivity and ease of fabrication. The sensor's structure was devised and analyzed using the Finite Element Method (FEM) of COMSOL v5.5, with a focus on exploring the impact of varying geometric parameters on its overall performance. The simulation utilized extremely fine mesh elements to ensure the utmost accuracy. Excitation between the core and plasmonic modes is achieved using Gold (Au) nanowires. The determination of the sensor's wavelength sensitivity involves assessing the resonance wavelength shift between samples of normal and cancerous cells. Simultaneously, the measurement of amplitude sensitivity is accomplished through a comparison of the amplitudes associated with their respective confinement losses. Various parameters of the PCF were varied during the experimentation, leading to the achievement of exceptionally high Amplitude Sensitivity (AS) of −273.16 RIU−1, −286.58 RIU−1, −455.59 RIU−1, −698.76 RIU−1, −1172.72 RIU−1 and −1971.30 RIU−1 for Skin Cancer, Cervical Cancer, Blood Cancer, Adrenal Gland Cancer, Breast Type-1 Cancer and Breast Type-2 Cancer respectively. Additionally, the Wavelength Sensitivity (WS) values were found to be 6500 nm/RIU, 14583.33 nm/RIU, 16428.57 nm/RIU, 25714.28 nm/RIU, 32857.14 nm/RIU, and 35714.28 nm/RIU for the same cancer types, respectively. The achieved resolutions for wavelength sensitivity are 1.54×10−5 RIU, 6.86×10−6 RIU, 6.09×10−6 RIU, 3.89×10−6 RIU, 3.04×10−6 RIU and 2.80×10−6 RIU, while the resolutions for amplitude sensitivity are 7.32×10−5 RIU, 8.37×10−5 RIU, 3.07×10−5 RIU, 2.00×10−5 RIU, 1.19×10−5 RIU and 7.10×10−6 RIU for the respective cancer types mentioned above. The design of the presented biosensor is notably uncomplicated and can be readily manufactured using contemporary fabrication techniques. In summary, the remarkable sensitivity exhibited by the proposed SPR-based PCF (SPR-PCF) biosensor, shows significant potential for enhancing the detection of cancer cells.

Advancements in MXene Composite Materials for Wearable Sensors: A Review.

In recent years, advancements in the Internet of Things (IoT), manufacturing processes, and material synthesis technologies have positioned flexible sensors as critical components in wearable devices. These developments are propelling wearable technologies based on flexible sensors towards higher intelligence, convenience, superior performance, and biocompatibility. Recently, two-dimensional nanomaterials known as MXenes have garnered extensive attention due to their excellent mechanical properties, outstanding electrical conductivity, large specific surface area, and abundant surface functional groups. These notable attributes confer significant potential on MXenes for applications in strain sensing, pressure measurement, gas detection, etc. Furthermore, polymer substrates such as polydimethylsiloxane (PDMS), polyurethane (PU), and thermoplastic polyurethane (TPU) are extensively utilized as support materials for MXene and its composites due to their light weight, flexibility, and ease of processing, thereby enhancing the overall performance and wearability of the sensors. This paper reviews the latest advancements in MXene and its composites within the domains of strain sensors, pressure sensors, and gas sensors. We present numerous recent case studies of MXene composite material-based wearable sensors and discuss the optimization of materials and structures for MXene composite material-based wearable sensors, offering strategies and methods to enhance the development of MXene composite material-based wearable sensors. Finally, we summarize the current progress of MXene wearable sensors and project future trends and analyses.

Hybrid Organic-Si C-MOSFET Image Sensor Designed with Blue-, Green-, and Red-Sensitive Organic Photodiodes on Si C-MOSFET-Based Photo Signal Sensor Circuit.

The resolution of Si complementary metal-oxide-semiconductor field-effect transistor (C-MOSFET) image sensors (CISs) has been intensively enhanced to follow the technological revolution of smartphones, AI devices, autonomous cars, robots, and drones, approaching the physical and material limits of a resolution increase in conventional Si CISs because of the low quantum efficiency (i.e., ~40%) and aperture ratio (i.e., ~60%). As a novel solution, a hybrid organic-Si image sensor was developed by implementing B, G, and R organic photodiodes on four n-MOSFETs for photocurrent sensing. Photosensitive organic donor and acceptor materials were designed with cost-effective small molecules, i.e., the B, G, and R donor and acceptor small molecules were Coumarin6 and C_60, DMQA and MePTC, and ZnPc and TiOPc, respectively. The output voltage sensing margins (i.e., photocurrent signal difference) of the hybrid organic-Si B, G, and R image sensor pixels presented results 17, 11, and 37% higher than those of conventional Si CISs. In addition, the hybrid organic-Si B, G, and R image sensor pixels could achieve an ideal aperture ratio (i.e., ~100%) compared with a Si CIS pixel using the backside illumination process (i.e., ~60%). Moreover, they may display a lower fabrication cost than image sensors because of the simple image sensor structure (i.e., hybrid organic-Si photodiode with four n-MOSFETs).

Research on design technology of fiber optic fuel level sensor with novel structure

Traditional aircraft fuel level sensors, represented by capacitive fuel level sensors, have inherent shortcomings, making it difficult to meet the increasing aviation needs in terms of intrinsic safety and electromagnetic interference resistance. Therefore, this article studies the design technology of fiber optic fuel level sensors. By analyzing various optical fiber liquid level measurement methods, the fiber Bragg grating method that best meets practical needs is selected, and a novel and reasonable sensor structure design is achieved. Specifically, in order to improve the measurement accuracy, a lever-type sensitivity enhancing structure based on flexure hinge is studied in this paper. Combined with the metal diaphragm, it can generate higher axial strain on the fiber grating under a given liquid pressure. In order to ensure the practicality of the sensor, this paper analyzes the interference factors that may cause the measurement error in the actual fuel tank. Correspondingly, this paper proposes a design of fixed distance double measuring points to compensate the influence of posture, uses the reference fiber grating method to compensate the influence of temperature, and designs a reasonable assembly and sealing scheme. To verify the rationality of the design, the sensor test platform is built and the sensor function is tested comprehensively. The results show that the sensor has good precision and can achieve expected compensation effect.

Nucleic Acid Sensor-Mediated PANoptosis in Viral Infection.

Innate immunity, the first line of host defense against viral infections, recognizes viral components through different pattern-recognition receptors. Nucleic acids derived from viruses are mainly recognized by Toll-like receptors, nucleotide-binding domain leucine-rich repeat-containing receptors, absent in melanoma 2-like receptors, and cytosolic DNA sensors (e.g., Z-DNA-binding protein 1 and cyclic GMP-AMP synthase). Different types of nucleic acid sensors can recognize specific viruses due to their unique structures. PANoptosis is a unique form of inflammatory cell death pathway that is triggered by innate immune sensors and driven by caspases and receptor-interacting serine/threonine kinases through PANoptosome complexes. Nucleic acid sensors (e.g., Z-DNA-binding protein 1 and absent in melanoma 2) not only detect viruses, but also mediate PANoptosis through providing scaffold for the assembly of PANoptosomes. This review summarizes the structures of different nucleic acid sensors, discusses their roles in viral infections by driving PANoptosis, and highlights the crosstalk between different nucleic acid sensors. It also underscores the promising prospect of manipulating nucleic acid sensors as a therapeutic approach for viral infections.

Anisotropic Sensing Performance in a High-Sensitivity Surface Plasmon Resonance Sensor Based on Few-Layer Black Phosphorus.

Few-layer black phosphorus (FLBP) is a highly promising material for high sensitivity label-free surface plasmon resonance (SPR) sensors due to its exceptional electrical, optical, and mechanical properties. FLBP exhibits inherent anisotropy with different refractive indices along its two main crystal orientations, the zigzag and armchair axes. However, this anisotropic property is often overlooked in FLBP-based sensors. In this study, we conducted a comprehensive investigation of the SPR reflectivity and phase in a BK7-Ag-FLBP structure to understand the influence of the stacking sequence and the number of FLBP layers on the sensing performance. Clear resonant angle shifts caused by different stacking sequences of FLBP could be observed both theoretically and experimentally. In the theoretical study, the highest reflective and phase sensitivities were achieved with a 12-layer black phosphorus (BP) structure. The reflectivity sensitivity reached 287.9°/refractive index units (RIU) with the zz stacking 12-layer BP film exhibiting a sensitivity 76°/RIU higher than the ac stacking structure. Similarly, the phase sensitivity reached 1162°/RIU with the zz stacking 12-layer BP structure showing a sensitivity 276.9°/RIU higher than the ac stacking structure. The electric field distribution of the 12-layer BP structure with four different stacking sequences has also been analyzed. In the experiment study, the well-known Attenuated Total Reflection (ATR) θ-2θ SPR setup is utilized to detect the reflectivity and phase of BK7-Ag-FLBP structures. The FLBP samples with the same thickness but different stacking sequences show significant resonant angle shift (0.275°) and maximum phase difference variation (34.6°). The FLBP sample thickness and crystal orientations have been demonstrated using the angular-resolved polarized Raman spectroscopy (ARPRS). These theoretical and experimental results provide strong evidence that the stacking sequences of FLBP have a significant impact on the sensing performance of SPR sensors. By harnessing the anisotropic properties of materials like FLBP, novel structures of anisotropic-2D material-based SPR sensors could open up exciting possibilities for innovative applications.

Research on the application of interferometric optical fiber sensors in high-pressure gas pipelines

The advantages of fiber optic sensors based on fiber optic interferometers with explosion-proof safety in gas pipeline monitoring has gradually emerged. A monitoring system for natural gas pipelines was designed and implemented using a Michelson interferometer as the core structure of the fiber optic sensor and processed the collected data using phase carrier generation demodulation algorithms. Addressing practical issues such as phase wrapping and arm length difference losses, an improved phase carrier demodulation algorithm based on tangent transformation and arctangent-differential self-cross-multiplication was proposed. Field experiments were conducted in gas valve chambers, to analyze the characteristics of leak signals in the pipeline. This study lays the foundation for the application of fiber optic interferometer sensors in gas pipeline monitoring, promising enhanced safety and efficiency.

Multi-mode fiber Bragg grating for simultaneous detection of strain, torsion and temperature

In this study, a fiber Bragg grating sensor utilizing multi-mode optical fiber (MM-FBG) is proposed. This sensor can simultaneously detect both temperature and torsion, or strain and torsion. Unlike single-mode fiber, the multiple modes of multi-mode fiber can generate several reflection peaks within the FBG area, increasing data capacity and enabling multi-parameter detection. By monitoring the center wavelength and reflection intensity of the MM-FBG reflection peaks, the sensor can detect temperature, torsion, and strain simultaneously. This approach simplifies parameter characterization compared to traditional methods, reducing signal interference and enhancing the clarity of experimental results. Experimental findings demonstrate that the MM-FBG sensor structure exhibits maximum sensitivities of 0.571 dBm/°/cm for torsion, 12 pm/°C for temperature, and 0.7411 pm/με for strain. Therefore, the fiber sensor proposed in this study shows great potential for monitoring bridge and tunnel structures and for civil engineering applications.

Recyclable Bimodal Polyvinyl Alcohol/PEDOT:PSS Hydrogel Sensors for Highly Sensitive Strain and Temperature Sensing.

Multimodal flexible sensors, consisting of multiple sensing units, can sense and recognize different external stimuli by outputting different types of response signals. However, the recovery and recycling of multimodal sensors are impeded by complex structures and the use of multiple materials. Here, a bimodal flexible sensor that can sense strain by resistance change and temperature by voltage change was constructed using poly(vinyl alcohol) hydrogel as a matrix and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) as a sensing material due to its conductivity and thermoelectric effect. The plasticity of hydrogels, along with the simplicity of the sensor's components and structure, facilitates easy recovery and recycling. The incorporation of citric acid and ethylene glycol improved the mechanical properties, strain hysteresis, and antifreezing properties of the hydrogels. The sensor exhibits a remarkable response to strain, characterized by high sensitivity (gauge factor of 4.46), low detection limit (0.1%), fast response and recovery times, minimal hysteresis, and excellent stability. Temperature changes induced by hot air currents, hot objects, and light cause the sensor to exhibit high response sensitivity, fast response time, and good stability. Additionally, variations in ambient humidity and temperature minimally affect the sensor's strain response, and temperature response remains unaffected by humidity changes. The recycled sensors are essentially unchanged for bimodal sensing of strain and temperature. Finally, bimodal sensors are applied to monitor body motion, and robots to sense external stimuli.

Structure of plasmonic multi spectral Apta sensor and analyzing of bulk and surface sensitivity

In this work, a multispectral aptasensor structure, including a sub-layer and two side walls, was presented. The cells are positioned at the down and top of the structure, with the down cells oriented perpendicular to the walls and the top cells aligned parallel to the walls. The validity of the findings was verified by the utilization of a numerical simulation technique known as 3D Finite Difference Time Domain (FDTD). The biosensor under consideration exhibits sensitivities of 1093.7 nm/RIU, 754 nm/RIU, and 707.43 nm/RIU in mode III, mode II, and mode I, respectively. In the majority of instances, the quantity of analyte available is insufficient to coat the surface of the sensor thoroughly. Consequently, in this study, the evaluation of surface sensitivity was undertaken alongside bulk sensitivity. The surface sensitivity of the suggested structure for mode II in the sensor layer, with thicknesses of 10, 20, 30, and 70 nm, is measured to be 25, 78, 344, and 717.636 nm/RIU, respectively. Our design incorporates a unique arrangement of sub-layer and side walls, with cells positioned to maximize interaction with the target analyte. This innovative configuration, combined with Ag for its superior plasmonic properties, enables the detection of E. coli O157 with remarkable sensitivity.

3D Printed Hydrogel Sensor for Rapid Colorimetric Detection of Salivary pH.

Salivary pH is one of the crucial biomarkers used for non-invasive diagnosis of intraoral diseases, as well as general health conditions. However, standard pH sensors are usually too bulky, expensive, and impractical for routine use outside laboratory settings. Herein, a miniature hydrogel sensor, which enables quick and simple colorimetric detection of pH level, is shown. The sensor structure was manufactured from non-toxic hydrogel ink and patterned in the form of a matrix with 5 mm × 5 mm × 1 mm individual sensing pads using a 3D printing technique (bioplotting). The authors' ink composition, which contains sodium alginate, polyvinylpyrrolidone, and bromothymol blue indicator, enables repeatable and stable color response to different pH levels. The developed analysis software with an easy-to-use graphical user interface extracts the R(ed), G(reen), and B(lue) components of the color image of the hydrogel pads, and evaluates the pH value in a second. A calibration curve used for the analysis was obtained in a pH range of 3.5 to 9.0 using a laboratory pH meter as a reference. Validation of the sensor was performed on samples of artificial saliva for medical use and its mixtures with beverages of different pH values (lemon juice, coffee, black and green tea, bottled and tap water), and correct responses to acidic and alkaline solutions were observed. The matrix of square sensing pads used in this study provided multiple parallel responses for parametric tests, but the applied 3D printing method and ink composition enable easy adjustment of the shape of the sensing layer to other desired patterns and sizes. Additional mechanical tests of the hydrogel layers confirmed the relatively high quality and durability of the sensor structure. The solution presented here, comprising 3D printed hydrogel sensor pads, simple colorimetric detection, and graphical software for signal processing, opens the way to development of miniature and biocompatible diagnostic devices in the form of flexible, wearable, or intraoral sensors for prospective application in personalized medicine and point-of-care diagnosis.

Multimode interference methane sensor based on a ZIF-8/PDMS composite film.

A multimode interference methane sensor based on a ZIF-8/PDMS composite film is proposed. The sensing principle is that the refractive index of the ZIF-8/PDMS composite film changes when it adsorbs methane, leading to a measurable optical path difference during the coupling of the cladding higher-order modes and the fundamental mode in the multimode interference fiber (MMI). The environmental methane concentration is then detectable by detecting the wavelength shifts of the interference peaks in the resulted spectrum. Through simulations and experiments aimed at enhancing sensor sensitivity, we optimized three parameters within the sensor structure: the length of the Tapered Single-Mode Fiber (TSMF), the composite film thickness, and the TSMF taper diameter. The experimental results indicate that the sensor's sensitivity reaches a maximum of 0.231 nm%-1. Additionally, the sensor exhibits excellent structural stability and measurement repeatability. The response time is as short as 40 s, and the recovery time ranges between 3 and 5 min. The proposed multimode interferometric methane sensor based on the ZIF-8/PDMS composite film has great potential to support highly sensitive methane concentration detection in many applications.