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A MEMS Accelerometer Based on Wavelength Modulation Using an Integrated Blazed Grating
摘要： This paper reports a MEMS optical fiber accelerometer with an integrated blazed grating as wavelength modulation component. The accelerometer includes a V-shape cantilever beam, a vertically symmetrical proof mass and an integrated blazed grating. The accelerometer prototype is fabricated with bulk micromachining processes and is tested. The bandwidth of the accelerometer is 200Hz. The optical sensitivity and nonlinearity of the measure range ±5.2g is 1.63nm/g @100Hz and 0.06% respectively. The x-axis and y-axis cross-axis sensitivities are 2% and 4.5% respectively. In the full temperature range of -20?C to 200 ?C, the temperature sensitivity is 2.8pm/ ?C. Thanks to the mentioned characteristics, the proposed MEMS accelerometer could have a wide range of applications, such as rail traffic and attitude heading sensing applications.
关键词： blazed grating,microsensors,optical fiber sensors,micromachining,Accelerometers,Microelectromechanical systems
更新于2025-09-10 09:29:36
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Improving the Performance of the Optical Antenna for Integrated LIDAR with Optical Phased Arrays through High Contrast Grating Structure on SOI Substrate
摘要： A novel optical antenna for integrated LIDAR with optical phased arrays is proposed and simulated. A HCG structure is used to achieve extremely efficient emission. The emission efficiency is as high as 93.94% at 1550 nm, which exceeds 50% in a range of wavelength from 1480 nm to 1620 nm. The antenna can achieve a perfect grating lobe suppression with background suppression of 28.4dB when the phase difference between adjacent waveguides is 0. A 16-wire optical phased arrays LIDAR can easily achieve a scan range of ±22.8°×20.2° with a beam width of 2.4°×2.5°, by employing the optical antenna proposed.
关键词： SOI substrate,high contrast grating,optical phased arrays,LIDAR,optical antenna
更新于2025-09-10 09:29:36
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Wavelength-Flattened Directional Coupler Based Mid-Infrared Chemical Sensor Using Bragg Wavelength in Subwavelength Grating Structure
摘要： In this paper, we report a compact wavelength-flattened directional coupler (WFDC) based chemical sensor featuring an incorporated subwavelength grating (SWG) structure for the mid-infrared (MIR). By incorporating a SWG structure into directional coupler (DC), the dispersion in DC can be engineered to allow broadband operation which is advantageous to extract spectroscopic information for MIR sensing analysis. Meanwhile, the Bragg reflection introduced by the SWG structure produces a sharp trough at the Bragg wavelength. This sharp trough is sensitive to the surrounding refractive index (RI) change caused by the existence of analytes. Therefore, high sensitivity can be achieved in a small footprint. Around fivefold enhancement in the operation bandwidth compared to conventional DC is achieved for 100% coupling efficiency in a 40 μm long WFDC experimentally. Detection of dichloromethane (CH2Cl2) in ethanol (C2H5OH) is investigated in a SWG-based WFDC sensor 136.8 μm long. Sensing performance is studied by 3D finite-difference time domain (FDTD) simulation while sensitivity is derived by computation. Both RI sensing and absorption sensing are examined. RI sensing reveals a sensitivity of ?0.47% self-normalized transmitted power change per percentage of CH2Cl2 concentration while 0.12% change in the normalized total integrated output power is realized in the absorption sensing. As the first demonstration of the DC based sensor in the MIR, our device has the potential for tertiary mixture sensing by utilizing both changes in the real and imaginary part of RI. It can also be used as a broadband building block for MIR application such as spectroscopic sensing system.
关键词： subwavelength grating,waveguide coupler,nanophotonics,photonics sensors,mid-infrared
更新于2025-09-10 09:29:36
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Research on high resolution fiber Bragg grating sensing technology based on high speed parallel sampling
摘要： The high resolution fiber Bragg sensing system based on high speed parallel sampling technology is proposed. According to the Rayleigh criterion, it is generally believed that the number of the measured data of the fiber grating reflection spectrum is limited to the resolution of the wavelength measurement device. So, in order to achieve high spectral resolution, high resolution wavelength measurement devices, at the same time, to achieve small variations of the transmission wavelength of the Fabry–Perot (FP) filter, the high bit digital-to-analog converter (DAC) was adopted to generates small step drive voltages, these will greatly increase the cost of the system. However, in this paper, the fiber Bragg sensing system with the low resolution FP filter and low bit DAC achieves the high resolution wavelength measurement by using the high speed parallel sampling. In addition, the resolution of wavelength in fiber grating sensing system is analyzed theoretically.
关键词： Parallel sampling technology,Wavelength resolution,Fiber Bragg grating,Optical fiber sensing
更新于2025-09-10 09:29:36
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Reflectance spectra characteristics from an SPR grating fabricated by nano-imprint lithography technique for biochemical nanosensor applications
摘要： In this paper, we report our research work on developing a Surface Plasmon Resonance (SPR) element with sub-micron (hundreds of nanometers) periodicity grating structure. This grating structure was fabricated by using a simple nano-imprint lithography technique from an organically siloxane polymers, which was then covered by nanometer thin gold layer. The formed grating structure was a very well defined square-shaped periodic structure. The measured reflectance spectra indicate the SPR wave excitation on this grating structure. For comparison, the simulations of reflectance spectra have been also carried out by using Rigorous Coupled-Wave Analysis (RCWA) method. The experimental results are in very good agreement with the simulation results.
关键词： biochemical nanosensor,SPR,grating,nano-imprint lithography,reflectance spectra
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Langkawi, Malaysia (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Design of a Grating Assisted Mode-Division Multiplexer
摘要： This paper presents design of a grating assisted mode-division multiplexer in silicon slab waveguide with 5 mode channels using coupled mode theory and transfer matrix method.
关键词： mode-division multiplexing,co-directional coupling,coupling length,contra-directional coupling,grating
更新于2025-09-09 09:28:46
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Quantum reflection of rare-gas atoms and clusters from a grating
摘要： Quantum re?ection is a universal property of atoms and molecules when scattered from surfaces in ultracold collisions. Recent experimental work has documented the quantum re?ection and diffraction of He atoms, dimers, trimers, and neon atoms when re?ected from a grating. Conditions for the observation of emerging beam resonances have been discussed and measured. In this paper, we provide a theoretical simulation of the quantum re?ection from a grating for those systems. We con?rm the universal dependence on the incident de Broglie wavelength with the threshold angles where the emerging beam resonances are observed. However, the angular dependence of the re?ection ef?ciencies, that is, the ratio of scattered intensity into speci?c diffraction channels relative to the total intensity is found to be dependent on the details of the particle surface interaction.
关键词： clusters,diffraction,rare-gas atoms,quantum re?ection,grating
更新于2025-09-09 09:28:46
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Controllable generation of second-harmonic vortex beams through nonlinear supercell grating
摘要： Lithium niobate (LiNbO3) nonlinear photonic crystals have been widely used in nonlinear wave front modulation for the p-phase difference between the second-harmonic (SH) waves from positive and negative domains. Aided by optimizing algorithms, we can control the diffraction patterns of SH vortex beams by designing nonlinear fork gratings with supercell structures in LiNbO3 crystals. In experiment, we demonstrate that the diffraction energies can be equally distributed in each order or concentrated on certain orders, in agreement with theoretical designs. Potential applications include controllable vortex beam generation, nondestructive parallel vortex detection, and so on.
关键词： quantum information processing,Lithium niobate,optical communication,nonlinear photonic crystals,supercell grating,second-harmonic vortex beams,nonlinear optics
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Portland, OR, USA (2018.11.13-2018.11.14)] 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Analog Photonic Timing Equalization Method for Multi-Channel RF Photonic Links
摘要： A new photonic timing equalization approach is presented to compensate the group delay among multiple signals in an analog photonic link. The results show the group delay variation across multiple RF photonic channels can be significantly compensated with 96.2% reduction after the equalization.
关键词： Phase conjugation,Analog photonic link,Arrayed waveguide grating(AWG),Group delay
更新于2025-09-09 09:28:46
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[IEEE 2018 Condition Monitoring and Diagnosis (CMD) - Perth, WA (2018.9.23-2018.9.26)] 2018 Condition Monitoring and Diagnosis (CMD) - Usability of fiber Bragg grating sensors for the fatigue life monitoring of overhead transmission lines
摘要： Fretting fatigue of transmission lines, caused by Aeolian vibration, always leads to catastrophic failure of conductors. The fatigue life monitoring of overhead transmission lines is an effective method to foresee strands broken of the conductor. Fatigue severity is usually expressed by alternating bending stress which occurs in the vicinity of suspension clamps during vibration. Given that it is hard to measure the fatigue stress directly, according to IEEE, alternating bending amplitude is recommended as a substitute measured parameter for fatigue life. In this paper, an on-line monitoring system based on a fiber- optic acceleration sensor is designed to analyze the fatigue life of overhead transmission lines in Aeolian vibration surveillance. Considering its superior performance of anti-electromagnetic interference, Fiber Bragg Grating (FBG) sensor is used to measure alternating bending amplitude of overhead transmission lines. And a Cumulative Fatigue Damage (CFD) method, which is based on alternating bending amplitude for vibration and the Stress-Cycle (S-N) curves, is proposed to calculate the fatigue life of overhead transmission lines. A case study of the one-month measurement data of Aeolian vibration for 1000kV Ultra-High Voltage (UHV) transmission lines is presented. Then an on-line monitoring system based on a fiber-optic acceleration sensor is designed to analyze the fatigue life of overhead transmission lines in Aeolian vibration surveillance.
关键词： Fretting fatigue,Aeolian vibration,life prediction,fiber Bragg grating
更新于2025-09-09 09:28:46