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Real-time signal processing for sub-THz range grating-based distributed fiber sensing
摘要： Distributed optical fiber sensors are an increasingly utilized method of gathering distributed strain and temperature data. However, the large amount of data they generate presents a challenge that limits their use in real-time, in situ applications. This article describes a parallel and pipelined computing architecture that accelerates the signal-processing speed of sub-terahertz fiber sensor arrays, maintaining high spatial resolution while allowing for expanded use of real-time sensing and control applications. The computing architecture described was successfully implemented in a field programmable gate array chip. The signal processing for the entire array takes only 12 system clock cycles. In addition, this design removes the necessity of storing any raw or intermediate data.
关键词： distributed optical fiber sensors,real-time signal processing,sub-THz range,FPGA,grating-based
更新于2025-09-10 09:29:36
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Application of Fiber Bragg Grating Acoustic Emission Sensors in Thin Polymer-Bonded Explosives
摘要： Fiber Bragg grating (FBG) acoustic emission (AE) sensors have been used in many applications. In this paper, based on an FBG AE sensor, the sensing principle of the interaction between the AE wave and the sensor is introduced. Then, the directionality of the FBG AE sensor on the surface of a thin polymer-bonded explosive (PBX) material is studied. Finally, the time coefficient location method is proposed to correct the AE time detected by the FBG AE sensor, thereby improving the accuracy of location experiments.
关键词： directionality,polymer-bonded explosives,time coefficient location method,fiber Bragg grating acoustic emission sensor
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Silicon Photonic Modulator using Mode Conversion with Asymmetric Sidewall Bragg Gratings
摘要： An asymmetric sidewall grating allows to operate a Bragg modulator in reflection without circulator and with less than 1.5 dB on-chip loss. An asymmetric Y-branch directs the incident TE0 mode to the grating, while the reflected TE1 mode is guided to the drop port.
关键词： Y-branch,Silicon photonic modulator,Bragg grating,multi-mode waveguide
更新于2025-09-10 09:29:36
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Millisecond-order X-ray phase tomography with a fringe-scanning method
摘要： We successfully realized millisecond-order X-ray phase tomography using a fringe-scanning method in grating-based X-ray interferometry. We obtained phase tomograms with a measurement time of 4.43 ms using a white synchrotron X-ray beam. The use of a fringe-scanning method enables us to achieve not only a higher spatial resolution but also a higher signal-to-noise ratio than that attained by the Fourier transform method. In addition, our approach can be applied to realize four-dimensional or high-throughput X-ray tomography for samples that can be rotated at a high speed.
关键词： fringe-scanning method,grating-based X-ray interferometry,white synchrotron X-ray beam,X-ray phase tomography,millisecond-order
更新于2025-09-10 09:29:36
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Integrated On-chip Bragg Time-Delay System for Thermo-Optical Control of a Microwave Antenna
摘要： This theoretical modeling-and-simulation paper presents designs and projected performance of ~1550-nm silicon-on-insulator beamsteering of a microwave phased-array antenna by the use of true time delays. The tunable on-chip optical delay line is a cascade connection of waveguide Bragg grating resonators (WBGRs) separated by a piece of straight waveguide. The notch in the reflectivity spectrum is translated along the wavelength axis by means of a low-power TO heater stripe atop the grating, inducing a time delay that depends upon the line position of the WBGR affected by TO switching. The filter resonator is a new in-guide array of identical Bragg structures, each one comprising N closely coupled phase-shifted Bragg-grating resonators. The length of each grating cavity in an N group is chosen according to the Butterworth filter technique to provide one resonant spectral profile with 40 GHz optical bandwidth. Finally, we examined the performances of the beamformer system operating in the X and Ku bands, respectively. The investigation demonstrated that steering angles up to 48° are feasible by assuming a minimum steering angle of 8° and a minimum WBGR spacing of about 354 and 236 μm for X and Ku bands, respectively.
关键词： Bragg grating resonators,Microwave Photonics,True Time Delays
更新于2025-09-10 09:29:36
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Mechanically Tunable Bilayer Composite Grating for Unique Light Manipulation and Information Storage
摘要： Composite gratings play important roles in modern information technology. However, such gratings are generally based on the same structural pattern with limited types, and their structural parameters are difficult to tune, which greatly limit their application. A mechanically tunable composite grating in bilayer film, which orthogonally couples a sinusoidal phase grating and a rectangular phase grating, is developed here. The structural parameters of the grating can be well tuned by mechanically stretching or releasing the grating in the uniaxial direction. Naturally, this property allows tunable light manipulation: that is, a single incident laser beam can be split into a 2D diffraction beams array, and the intensity and propagation angle of each diffraction beam can be precisely controlled via mechanical manipulation of the grating. A theoretical model based on scalar diffraction theory that can quantitatively describe and accurately predict this light manipulation is further established. In addition, after treatment with an electron beam, the tunable structures can be immobilized, which enables the storage of information in the bilayer film. This work may open up new pathways for composite grating fabrication and further extend the applications of composite gratings in diverse fields.
关键词： bilayer composite grating,light manipulation,information storage,mechanically tunable
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom) - Ostrava, Czech Republic (2018.9.17-2018.9.20)] 2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom) - SMART medical polydimethylsiloxane for monitoring vital signs of the human body
摘要： This paper focuses on current trends in non-invasive monitoring of vital functions of the human body using SMART sensors. It describes a sensor pad made of a thin layer of polydimethylsiloxane (PDMS) with one symmetrically positioned fibre Bragg grating (FBG). The PDMS material is immune to electromagnetic interferences (EMI) and inert to human skin. By combining fibre-optic technology and PDMS, the SMART PAD sensor is formed which is used not only for classical hospital environments, but also for electromagnetically interfered environments, for example magnetic resonance imaging (MRI). The basic monitored parameters described are the respiratory rate (RR) and heart rate (HR) of the human body. The results were obtained in a laboratory environment in a group of 10 volunteers upon their written consent. The acquired results were compared by the Bland-Altman (B-A) method, which belongs to the group of statistical methods in biomedical research.
关键词： heart rate,respiratory rate,fiber Bragg grating,vital sign monitoring,polydimethylsiloxane
更新于2025-09-10 09:29:36
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41.5: Head-mounted Display Based on Surface Relief Grating for Augmented Reality
摘要： A see-through head-mounted display (HMD) is demonstrated in the paper, which can present the user with information such as virtual symbols or images superimposed over real-world image. To meet the human eyes’ visual requirements under different situations, a large exit pupil of 2 to 5 times of the pupil size (about 2.4 mm) is required. To solve the problem, the HMD presented in the paper is a combination of micro-display of LCoS, imaging eyepiece and an exit pupil expander based on planar waveguide with slanted surface relief grating. Both transmission and reflection gratings are applied in the HMD design. Two system schemes are presented which expand the light only along one direction and two orthogonal directions, respectively. The system configuration and principle of operation are described in the paper.
关键词： exit pupil expander,augmented reality,surface relief grating,head-mounted display
更新于2025-09-10 09:29:36
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Nonlinear manipulation of surface plasmons on graphene-TMDC Bragg reflectors
摘要： In this study, we benefit from the nonlinear optical tunability of the graphene-transition metal dichalcogenide (G-TMDC) heterostructure and the strong confinement of the electromagnetic fields of surface plasmon polaritons (SPPs) on graphene in order to propose a highly tunable nonlinear optical Bragg reflector. Recently, two-dimensional (2D) TMDCs are the subject of intense researches because of their nonlinear optical properties at near infrared wavelengths which are very intriguing for various optical applications. We choose two kinds of 2D-TMDCs, MoSe2 and WSe2, with the strongest second order optical nonlinearity at near infrared range to properly design the periodic variation of the propagating SPP waves on the graphene layer. We utilize theoretical method of quantum electrostatic heterostructure to compute the dielectric function of graphene-TMDCs. Different nonlinearities of two TMDCs lead to noticeable tuning of the full width at half maximum (FWHM) and the central Bragg wavelength of the reflector which let design various optical devices. We design an add/drop filter, a nonlinear switch, and an AND/OR optical logic gate based on our proposed Bragg reflector. Our finite difference time domain numerical and transfer matrix analytical results reveal that by increment of the optical intensity up to 6 MW/cm2 which is below the pulse damage threshold of graphene, due to the second order nonlinearity, a 10-nm red-shift in central Bragg wavelength is observed and the 20-nm FWHM at linear regime decreases to 1.5 nm. The SPP intensities of 0.8 MW/cm2 and 1.53 MW/cm2 fulfill the requirements for AND and OR logical operations with 57 and 66.51 dB extinction ratios, respectively.
关键词： Nonlinear optical materials and devices,Surface plasmons,Nonlinear optics,Optical switches,Bragg grating
更新于2025-09-10 09:29:36
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A Kind of Vibration Sensor and Testing System in Electromechanical Equipment Based on Fiber Bragg Grating
摘要： Mechanical vibration analysis is an important index to measure the running state of the electromechanical equipment. The vibration signals contain the information about the equipment running state. This paper studies and designs the vibration monitoring system based on fiber Bragg grating (FBG). Through the finite element analysis simulation, optimizes the sensor's structure, and uses the labview software to compile the corresponding vibration monitoring analysis software. Finally verifies the detection effect of the monitoring system, through the pulse signal and continuous signal dynamic experimental analysis. The result of the experimental analysis shows: this vibration monitoring system can monitor the vibration information and analyze vibration state effectively. It has the advantages of reducing the temperature interference and lateral disturbance, and detects the vibration of three direction at the same time. So it is feasible to monitor the electromechanical equipment.
关键词： three-dimensional sensor,vibration monitoring analysis,electromechanical equipment,fiber Bragg grating
更新于2025-09-10 09:29:36