FBG Technology Research Articles

Plasmonic biosensing with tilted fiber Bragg gratings interrogated using a 512-pixel spectrometer.

Plasmonic tilted fiber Bragg gratings (TFBGs) are very efficient for fast, accurate, and minimally invasive biosensing. Their transmitted amplitude spectrum is a dense comb of narrowband cladding mode resonances (full width at half maximum < 1 nm) that is usually demodulated using highly resolved (wavelength resolution < 10 pm) devices. This work demonstrates the possibility of using a coarsely resolved spectrometer (166 pm) to read out the amplitude spectrum of a gold-coated TFBG. A refined analysis of the spectral content has allowed us to develop signal processing that provides a refractometric sensitivity of 2656 nm/RIU. This is a fivefold improvement compared to previously reported read-out techniques. Biosensing has then been successfully implemented with gold-coated TFBGs implemented in reflection mode for the detection of insulin, with specific antibodies grafted on the gold surface. Our experimental work is a first step toward the industrialization of the FBG technology, as it opens the door to fast parallel biosensing, profiting from the multiple sensing channels (up to 64) of the interrogator and its high processing speed (repetition rate up to 3 kHz).

Direct Measurement of Beam-Induced Heating on Accelerator Pipes With Fiber Optic Sensors: Numerical Analysis Validation

In the field of accelerator physics it is crucial to account for heating caused by the passage of high intensity beams into accelerator components. This phenomenon is known as Radio Frequency (RF) Beam Induced Heating (BIH) and requires, other than an accurate design stage, to constantly monitor temperature-related parameters during the accelerator operations. This enables to warn for critical malfunctions and to prevent possible damages. Monitoring needs to meet various requirements, such as multiplexing capabilities, distributed sensing possibilities, and robustness in harsh environments. Fiber Bragg Grating sensors (FBGs) have been proven to be an ideal solution that meets all these requirements. This study aims to validate the use of FBGs for direct measurement of RF BIH. A section of the beam pipe in the CERN Large Hadron Collider was modeled in terms of impedance, and the resulting RF BIH was computed based on the traveling beam. The results of the numerical simulation were compared with experimental data obtained by FBGs installed along the beam pipe. The analysis shows that FBGs can be a valuable beam diagnostic tool for monitoring accelerated high energy particle beams by measuring RF BIH and may provide useful insights for improving the design and operation of future accelerators. The study highlights the significant advancements of FBG technology in direct temperature measurement and assessment of RF BIH and serves as a promising solution for mitigating RF BIH in the demanding environment of particle accelerators.

Application of ultra-weak FBG technology in real-time monitoring of landslide shear displacement

Application of ultra-weak FBG technology in real-time monitoring of landslide shear displacement

Two-parameter method for identification and location of leaks based on weak FBG for steam pipelines

In this paper, an online steam pipeline leakage monitoring method, based on a weak-reflectivity optical fiber Bragg grating (wFBG) array for temperature–vibration hybrid sensing, is presented. This method meets the requirements of long-distance, large capacity, low false positive rate (FPR), and low false negative rate (FNR). The drawing tower online-writing FBG technology was used to write the wFBG (−40 dB), which has the advantages of high strength and good consistency. A large-capacity sensor network is realized using mixed time-division multiplexing and wavelength-division multiplexing technology. A novel temperature–vibration composite optical cable structure was designed to realize multi-parameter pipeline leakage monitoring. A chirped wFBG array with a spatial resolution of 3 m and a narrowband wFBG array with a spatial resolution of 1 m were combined in the same optical cable to simultaneously monitor the vibration and temperature of the pipeline. Leakage of the steam pipeline is accompanied by changes in the temperature and vibration signals. The leakage and its location can be identified more accurately by changes in these two parameters in the wFBG wavelength and interferometric phase. The field experiment results show that this temperature–vibration two-parameter detection system can accurately identify and locate steam pipeline leaks and reduce the FPR. This validates the feasibility of the wFBG array-based temperature–vibration hybrid sensing technology for monitoring steam pipeline leakage.

Direct on Chip Thermal Measurement in IGBT Modules Using FBG Technology—Sensing Head Interfacing

This paper assesses the suitability of the use of Fiber Bragg Grating Sensors for effective in-situ sensing of the IGBT junction temperature. To this end, the optical sensor is installed on the chip surface in a commercial IGBT module, enabling direct reading of its junction temperature. Two sensor interfacing configurations are evaluated by means of Finite Element simulations and experiments on a purpose designed laboratory test system. Experiments show the feasibility on the use of FBG sensing technology for reliable and effective real-time measurement of the junction temperature in a wide operating envelope of the tested IGBT device.

Research on FBG Technology Applied in Highway Soft Foundation Pore Pressure Monitoring

The pore water pressure monitoring of soft ground pavement is one of the important technical links in highway construction monitoring. The use of traditional electrical measuring instruments to monitor pore water pressure has disadvantages such as low degree of automation, non-real-time data transmission, and high manual monitoring costs. However, fiber grating monitoring technology has developed rapidly due to its advantages of stable data transmission, convenient collection, and dynamic monitoring. . Therefore, relying on the soft foundation pore water pressure monitoring project of Jiujiang Ring Expressway, the monitoring principle of the fiber grating seepage pressure sensor and the buried installation technology in the soft foundation are introduced. Through the long-term monitoring practice on the construction site, it is confirmed that the optical fiber monitoring system is applied to the soft foundation. The stability of base pore water pressure monitoring provides a reference for similar monitoring projects and engineering construction.

An Optical Fiber Transducer for Measuring Kinetics of Skull-Brain Interaction in a Surrogate Model of the Human Head Subjected to Blast Overpressure

This paper presents the development and validation of an in-fiber Bragg grating (FBG) transducer for measuring skull-brain kinetics within a surrogate headform used to assess protective headgear during blast exposure. The presented force transducer (6-mm nominal diameter) contains a multi-layered composite superstructure, and demonstrates linearity and repeatability in both impact-response calibrations and blast-loading conditions. Fourier analysis indicates that the presented transducer captures transient kinetics of blast overpressure with an average 0.12% difference in normalized Fourier amplitudes captured by the FBG and validated reference transducer. Time-domain analysis indicates the FBG transducer is repeatable with maximum coefficient of variance for repeated measures at 7.9%, whereas the validated reference transducer coefficient of variance is 9.1% (maximum) based on normalized data. The novel transducer is the first application of FBG technology to measure skull-brain kinetics following loading from a blast, and can be used to evaluate the mechanisms of energy-transfer into the head during blast exposure.

Methods of dilatometric investigations under extreme conditions and the case of spin-ice compounds

We give an overview on how dilatometric methods have been developed in the last decade. The concept of capacitive dilatometry was successfully adapted to dilution refrigerators with a resolution of 10−9. Miniaturized dilatometers with an overall diameter of 18 mm or less are optimally suited for measuring longitudinal and transversal components of the striction tensor. Going to another extreme, to the highest (pulsed) fields, optical methods, such as the FBG technology, were developed for investigations up to 100 T.As examples for utilizing dilatometry at low temperatures we show results for the spin-ice materials Dy2Ti2O7 and Ho2Ti2O7. To characterise the magneto-elastic coupling in these materials, we investigated the thermal expansion and magnetostriction between 80 mK and 15 K and in magnetic fields aligned along the [111] direction and found field-induced phases and strong correlations below 500 mK. Our data demonstrate, that the formation of the field-induced phase is strongly influenced by lattice distortions: any change in interatomic distances will result in a variation of the exchange couplings.

基于HHT的航空发动机液压管路系统管路故障诊断研究

针对航空发动机液压管路系统在实际工作中由于振动过大产生的卡箍松脱故障，通过电磁振动台模拟宽频域液压管路基础激励环境，采用光纤光栅分步式监测系统，利用HHT方法可以对航空发动机液压管路系统振动信号中的突变信号进行有效的侦测。HHT分析方法能够反映航空发动机液压管路系统的故障振动响应的不同状态，由此进行航空发动机液压管路系统振动信号的检测具体实施步骤。最后结果表明，采用HHT方法与光纤光栅监测系统能够实现航空发动机液压管路故障的定位和判定。 The objective in this paper is to present HHT method and FBG technology to analyze the aero-engine hydraulic pipeline vibration signal under fault states. Fault diagnosis and location of aero-engine hydraulic pipeline vibration signals based on HHT method and FBG method are ap-plied through HYPERLINK electromagnetic vibration table simulating wide frequency band under clamp loosing and trip state. The results tested in aero-engine hydraulic pipe show that HHT method can clearly reflect the real vibration characteristics of hydraulic pipe under different states. This method overcomes the disadvantage of the traditional Fourier transform (FFT) which cannot obtain the instantaneous frequency of aero-engines, and provides a new idea for the non- stationary vibration information of hydraulic pipe under different states. Fault diagnosis and location of the aero-engine hydraulic pipeline are confirmed by HHT and FBG method.

Research and Application of Fiber Bragg Grating Sensor in Geological Disaster Automation Monitoring

In this paper, fiber grating technology is used for accurately measure stresses, temperature and displacement. The paper introduces the basic principles of FBG technology and the wavelength demodulation method of FBG sensors, and put fiber grating technology into practical engineering projects. The paper design a optical fiber grating real-time automation monitoring system to distributed measure stress, temperature and displacement in geological disaster body, to provide effective technical supports for geological disaster prevention and mitigation.

Application of Optical Fiber Sensing Real-Time Monitoring Technology Using in Ripley Landslide

Nowadays, fiber optic technology has been used in sensing. Using the distributed optical fiber sensing technology in the landslide monitoring, the linear strain distribution information of the whole landslide can be obtained, and adopting the Fiber Bragg Grating sensing technology in the landslide monitoring, the key pot strain and displacement information can be gained. This paper firstly reviews the basic principle of optical fiber sensing, and then describes the optical fiber sensing real-time monitoring system by combining with FBG technology, BOTDR technology, database technology and web server technology, and finally presents a field application experiment using the real-time monitoring system in Ripley landslide in Canada. The experiment indicated that the real-time monitoring system can be realized real-time monitoring of FBG and BOTDR for landslide, and the experience can be extended to other landslide.

埋入式光纤Bragg光栅应变传感器在隧道二次衬砌中的监测研究

The performance degradation of secondary lining is the main disease that affects the operation of tunnel,monitoring the secondary lining is an important means to ensure the tunnel operate healthily.The changes of secondary lining are studied to apply embedded FBG strain sensor.According to the layout schemes of FBG and temperature compensation technology,the strain variation of the tunnel cross-section is analyzed.The results show that the data curve trend reflects changes in the tunnel secondary lining,the effective support is provided for disease forecasting further.

Study on the Applications of FBG Technology in River Level Monitoring

In order to overcome the disadvantage of low accuracy for traditional monitoring technologies of river level, and solve the problems in real-time data acquisition and remote transmission for the existing hydrological observation, we design a new monitoring system of river level based on fiber grating technology, which can realize high sensitivity and automatic monitoring of river level. The system has been put into practical application in a monitoring project and the measurement results indicate that this system is of such advantages as real-time capability, high accuracy, unattended operation, and can well meet the present requirements of hydrological observation and measurement.

Study on the Application of FBG Technology in Rainfall Monitoring

In order to overcome the disadvantage of low accuracy for traditional rainfall monitoring technologies, and solve the problems in real-time data acquisition, automatic processing and remote transmission for the existing meteorological observation, we design a new rainfall monitoring device based on fiber grating technology, which has such advantages as real-time capability, high sensitivity, high accuracy, unattended operation and can fairly meets the present requirements of meteorological observation.

One Year of FOS Measurements in CMS Experiment at CERN

Results are presented on the activity carried out by our research group, in collaboration with the SME Optosmart s.r.l. (an Italian spin-off company), on the application of Fiber Optic Sensor (FOS) techniques to monitor high-energy physics (HEP) detectors. Assuming that Fiber Bragg Grating sensors (FBGs) radiation hardness has been deeply studied for other field of application, we have applied the FBG technology to the HEP research domain. We present here the experimental evidences of the solid possibility to use such a class of sensors also in HEP detector very complex environmental side conditions. In particular we present more than one year data results of FBG measurements in the Compact Muon Solenoid (CMS) experiment set up at the CERN, where we have monitored temperatures (within CMS core) and strains in different locations by using FBG sensors during the detector operation with the Large Hadron Collider (LHC) collisions and high magnetic field. FOS data and FOS readout system stability and reliability is demonstrated, with continuous 24/24 h 7/7d data taking under severe and complex side conditions.

Novel applications of fiber bragg grating components for next-generation WDM systems

The main purpose of this paper is to present an overview of novel applications enabled by major improvements realized in FBG technology. First, we will review the principle of operation of FBG-based components and the numerous recording techniques used to fabricate those types of components. We will next show that this technology combined with new innovative manufacturing process is well suited to overcome the challenges imposed on optical components for next-generation WDM systems.

Estimation of DWDM Transmission for Broadband Access with FBG Technology

In this paper authors have measured amplitude transfer functions of FBG technology optical filters with 50 GHz and 100 GHz FWHM bandwidth and have evaluated their performance in 2.5 Gbit/s and 10 Gbit/s DWDM transmission system over a typical length of broadband access network. Reliable transmission is realized for eight channels 2.5 Gbit/s DWDM transmission system with 50 GHz FBG for 20 km of SSMF and for eight channels 10 Gbit/s DWDM transmission system with 50 GHz FBG for reduced distance (10 km of SSMF). Ill. 6, bibl. 10 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.111.5.346