- 标题
- 摘要
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- 实验方案
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Multi-parameter sensor based on single Long Period Grating in Panda fiber for the simultaneous measurement of SRI, temperature and strain
摘要： In this work, a three-parameter sensor for the simultaneous measurement of surrounding refractive index (SRI), temperature and strain is presented. It is based on a single Long Period Grating (LPG) written in a polarization-maintaining Panda fiber, by means of a simple technique based on Electric Arc Discharge. For the purpose, it is performed the monitoring of the wavelength shift of three different resonances, each one associated to a different cladding mode. Moreover, the set of resonances is acquired for two polarizations of the input light, i.e. aligned to the slow and fast axis of the fiber. The three-parameter sensing is promoted by the fact that the resonance dips show different sensitivities to SRI, temperature and strain, which change their magnitudes and signs when the polarization is switched. It was demonstrated that the sensor can be applied to simultaneously measure SRI in range 1.33–1.40, temperatures comprised in 20–60 °C, and strain of hundreds of με. This device could find application in the fields of materials science and structural health monitoring.
关键词： Refractive index sensor,Temperature sensor,Fiber grating sensor,Strain sensor,Multi-parametric sensor,Long period grating
更新于2025-11-28 14:24:03
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - CO<inf>2</inf> Laser Inscribed Helical Long-Period Grating in Six-Mode Fiber
摘要： We fabricated the helical long-period fiber grating in a six-mode fiber with CO2 laser. The grating realize mode conversion from LP01 mode to LP21 mode with high efficiency. The mode coupling and sensing characteristics are investigated.
关键词： six-mode fiber,Helical long-period grating,mode converter
更新于2025-11-28 14:24:03
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Ultrasensitive tantalum oxide nano-coated long-period gratings for detection of various biological targets
摘要： In this work we discussed a label-free biosensing application of long-period gratings (LPGs) optimized in refractive index (RI) sensitivity by deposition of thin tantalum oxide (TaOx) overlays. Comparing to other thin film and materials already applied for maximizing the RI sensitivity, TaOx offers good chemical and mechanical stability during its surface functionalization and other biosensing experiments. It was shown theoretically and experimentally that when RI of the overlay is as high as 2 in IR spectral range, for obtaining LPGs ultrasensitive to RI, the overlay’s thickness must be determined with subnanometer precision. In this experiment the TaOx overlays were deposited using Atomic Layer Deposition method that allowed for achieving overlays with exceptionally well-defined thickness and optical properties. The TaOx nano-coated LPGs show RI sensitivity determined for a single resonance exceeding 11,500 nm/RIU in RI range nD=1.335-1.345 RIU, as expected for label-free biosensing applications. Capability for detection of various in size biological targets, i.e., proteins (avidin) and bacteria (Escherichia coli), with TaOx-coated LPGs was verified using biotin and bacteriophage adhesin as recognition elements, respectively. It has been shown that functionalization process, as well as type of recognition elements and target analyte must be taken into consideration when the LPG sensitivity is optimized. In this work optimized approach made possible detection of small in size biological targets such as proteins with sensitivity reaching 10.21 nm/log(ng/ml).
关键词： protein detection,label-free biosensing,optical fiber sensor,tantalum oxide,bacteria detection,long-period grating,atomic layer deposition
更新于2025-11-28 14:23:57
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Optical and Digital Key Enabling Techniques for SDM-Based Optical Networks
摘要： In order to support, in a cost-effective way, the data capacity demand in the context of future 5G networks, a new set of advanced technologies need to be explored, as it is the case of space-division multiplexing (SDM) along with energy efficient coherent detection based modulation formats. This paper presents the recent results on enabled optical networks based on SDM for high capacity optical networks compatible with 5G network infrastructure and data center connectivity. In particular, we demonstrate the viability of using Long-Period Gratings (LPGs) in multi-core fibers (MCFs) to develop different components for multicore-based SDM systems, such as pump couplers and core/wavelength selective multi-core switches and couplers. Moreover, we also present and characterize the performance of different digital signal processing (DSP) algorithms and subsystems supporting optical coherent detection in SDM systems.
关键词： Coherent detection,long period grating,generalized Stokes space,digital signal processing,space-division multiplexing,space-division demultiplexing
更新于2025-09-23 15:23:52
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An interferometric structure with a dual-resonance long period grating for strain sensing
摘要： Spectral characteristics and amplitude tunability of a long period grating with a dual-resonance inside fiber loop mirror are studied in terms of applied stress caused by elongation. Inserting the polarization controller between grating and part of polarization maintaining fiber in the loop structure enables tuning of resonance and interferometric peaks. The maximum sensitivity of demonstrated sensor is of 1.943 dB/mε for the range of 1.1–4.4 mε. Combination of these two optical components allows to measure strain in a wider range comparing with sensors based on standard long period grating.
关键词： Fiber loop mirror,Polarization controller,Polarization maintaining fiber,Strain sensor,Long period grating
更新于2025-09-23 15:23:52
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EDC-Mediated Oligonucleotide Immobilization on a Long Period Grating Optical Biosensor
摘要： We present the development and simplification of label-free fiber optic biosensors based on immobilization of oligonucleotides on dual-peak long period gratings (dLPGs). This improvement is the result of a simplification of biofunctionalization methodology. A one-step 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated reaction has been developed for the straightforward immobilization of unmodified oligonucleotides on the glass fiber surface along the grating region, leading to covalent attachment of a 5′-phosphorylated probe oligonucleotide to the amino-derivatized fiber grating surface. Immobilization is achieved via a 5′phosphate-specific linkage, leaving the remainder of the oligonucleotide accessible for binding reactions. The dLPG has been tested in different external media to demonstrate its inherent ultrahigh sensitivity to the surrounding-medium refractive index (RI) achieving 50-fold improvement in RI sensitivity over the previously-published LPG sensor in media with RI’s relevant to biological assays. After functionalization, the dLPG biosensor was used to monitor the hybridization of complementary oligonucleotides showing a detectable oligonucleotide concentration of 4 nM. The proposed one-step EDC reaction approach can be further extended to develop fiber optic biosensors for disease analysis and medical diagnosis with the advances of label-free, real-time, multiplex, high sensitivity and specificity.
关键词： EDC-mediated reaction,Label-free,DNA,Oligonucleotide,Optical fiber biosensor,Long period grating
更新于2025-09-23 15:21:01
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Simultaneous in situ temperature and relative humidity monitoring in mechanical ventilators using an array of functionalised optical fibre long period grating sensors
摘要： An array of optical fibre long period gratings (LPGs) has been demonstrated for biomedical application to monitor temperature and relative humidity (RH) changes in the air delivered by a mechanical ventilator operating in different modes. The LPG array consists of two gratings, where one was kept bare to monitor the temperature change and the second was modified with 10 layers of silica nanoparticles to measure relative humidity. A mesoporous film was deposited on the surface of an optical fibre LPG using the layer-by-layer method. The sensor was calibrated in a bench model against a commercially available temperature and relative humidity sensor and sensitivity of the sensor was 0.46±0.01 nm/ oC and 0.53 nm/RH%, respectively. The tip of the sensor array was modified with reflection mirror and placed inside an endotracheal tube (ETT) and tested in typical clinical equipment to enable the in-situ real-time monitoring of humidity and temperature. Temperature and RH changes associated with the breathing frequency of 8 and 15 breaths per minute were successfully monitored using developed sensor array.
关键词： relative humidity (RH),Long period grating (LPG),healthcare monitoring,mechanical ventilation,endotracheal tube,temperature,optical fibre sensor,multiplexing
更新于2025-09-19 17:15:36
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Fabrication of surface corrugated Long Period Gratings on Plastic Optical Fibers for Refractive Index Sensing
摘要： We use a simple way to fabricate surface corrugated long period gratings (LPGs) on commercial plastic optical fibers (POFs) by die press print method. The so-obtained LPGs are proposed as refractive index (RI) sensors in this work. The LPGs imprinted on the POFs with different diameters are evaluated, and it shows that an LPG imprinted on a thin POF (with a diameter of 0.25mm) exhibits better RI sensing performance than that of the ones on thick POFs (with diameters of 0.5 and 1.0mm). When the LPG with period of 100μm, groove depth of 45μm was imprinted on the POF with a diameter of 0.25mm, the RI sensitivity of 1998%/RIU with a resolution of 2.70×10-4 RIU is obtained. The sensor is a low-cost solution for RI sensing purpose and with the features of simple structure, easy fabrication and intensity modulation at visible wavelengths.
关键词： Refractive index sensing,Long period grating,Plastic optical fiber
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Sensing Characteristics of Helical Long-Period Grating Inscribed in Graded Index Few Mode Fiber
摘要： Helical long-period grating fabricated in graded-index few-mode fiber was experimentally demonstrated. The high sensitivities corresponding to torque, curvature, temperature and surrounding refractive index are up to 0.293 nm/rad/m, 2.486nm/m-1, 0.095 nm/(cid:31) and 1242 nm/RIU, respectively.
关键词： helical long-period grating,sensing,graded-index few-mode fiber
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Analysis of core eccentricity on the long period grating in eccentric core fiber
摘要： theoretically. The variation of the transmission spectrum is calculated under different eccentricities on the basis of the coupled-mode theory. The calculation results indicate that the order of the cladding mode that has the largest coupling efficient with the core mode changes with the change of the core eccentricity, which results in the shift of the resonant peaks. In addition, the effective refractive index of the fundamental mode increases with the core eccentricity within a certain range. The model we have proposed can provide a valid reference for designing ECF and writing LPFG in the ECF.
关键词： Coupled-mode theory,Eccentric core fiber,Long period grating
更新于2025-09-16 10:30:52