A5108113285- Advanced Fiber Optic Sensors
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Optical Network Technologies
- Semiconductor Lasers and Optical Devices
- Optical Coherence Tomography Applications
- Photonic Crystal and Fiber Optics
- Optical Polarization and Ellipsometry
- Optical measurement and interference techniques
- Advanced Measurement and Metrology Techniques
- Geophysics and Sensor Technology
- Surface Roughness and Optical Measurements
- Optical Systems and Laser Technology
- Magneto-Optical Properties and Applications
- Advanced Chemical Sensor Technologies
- EEG and Brain-Computer Interfaces
- Spectroscopy and Chemometric Analyses
- Neuroscience and Neural Engineering
- Seismic Waves and Analysis
- Gas Sensing Nanomaterials and Sensors
- Epilepsy research and treatment
- Machine Learning and ELM
- Mechanical and Optical Resonators
- Photorefractive and Nonlinear Optics
- Neural Networks and Reservoir Computing
Guangdong University of Technology
2020-2024
Harbin Engineering University
2015-2024
Nanyang Technological University
2019
In this paper, we propose and demonstrate a spectral splicing method (SSM) for distributed strain sensing based on optical frequency domain reflectometry (OFDR), which can achieve km level measurement length, µɛ sensitivity 104 range. Based the traditional of cross-correlation demodulation, SSM replaces original centralized data processing with segmented achieves precise spectrum corresponding to each signal segment by spatial position correction, thus realizing demodulation. Segmentation...
We present and demonstrate a method based on periodic phase noise estimation in an optical frequency domain reflectometry (OFDR) capable of beyond 107 range-resolution-1 product (RRP) for the first time, which corresponds to 2.5 × improvement compared with state-of-the-art. The moving average filter is employed suppress amplification derivation process. Further, help third-order Taylor expansion, this provides highly precise noise, main factor impacting performance OFDR systems...
Considering that vehicle exhaust contributes to the majority of nitrogen oxides (NOx), which is harmful environment and climate, it important measure NOx concentrations in sustainable developments. This article proposes apply spectroscopic gas sensing methods an innovative deep learning network algorithm for obtaining high-precision data. The adopted mid-infrared sensor technology based on spectroscopy combined with advanced substrate-integrated hollow waveguide (iHWG) interface. Using...
A kind of hybrid fiber interferometer consisting a Sagnac (FSI), closed-cavity Fabry-Perot (FPI), and an open-cavity FPI is proposed for generating combined-Vernier-effect. Through adjusting the polarization-maintaining (PMF) length FSI, free spectral range (FSR) tailored to be similar that parallel-connected reference producing first Vernier effect, which spectrum used match sensing obtaining second effect. Noticeable lower upper envelopes are achieved in effects, respectively, so called...
Abstract Background: Epilepsy is a common neurological disorder that affects approximately 60 million people worldwide. Characterized by unpredictable neural electrical activity abnormalities, it results in seizures with varying intensity levels. Electroencephalography (EEG), as crucial technology for monitoring and predicting epileptic seizures, plays an essential role improving the quality of life epilepsy. Method: This study introduces innovative deep learning model, lightweight triscale...
A white light temporal interferometric technique for measurement of the quasi-distributed birefringence dispersion (BD) in a polarization maintain (PM) device with high accuracy based on weighted least square (WLS) method is presented. It verified theoretically and experimentally that WLS conventional ordinary (OLS) both are proportional to signal-to-noise ratio (SNR) interferogram, whereas holds higher scaling factor because it more suitable heteroscedastic model has unequal error variance....
A dual cross-axis interference polarization-maintaining fiber interferometer (DCAI-PMFI) for simultaneous measurement of strain and temperature is proposed. By using the cross-interference fast slow axes in with axis independent detection, common path interferometers (DCAIs) are realized. Since different refractive index thermo-optic coefficient, DCAIs have phase sensitivities to temperature. sensitivity matrix constructed. The can be adjusted by changing length ratio two arms DCAI-PMFI...
In this Letter, we present optical frequency domain polarimetry (OFDP), a novel, to the best of our knowledge, distributed polarization crosstalk (DPC) measurement method with dynamic range beyond 110 dB. It is based on swept-wavelength interferometry using tunable laser source (TLS) and delay line interferometer (DLI). The ultrahigh achieved by optimizing sweep rate TLS path difference DLI. Using OFDP, measured below –105 dB in LiNbO 3 waveguide modulator for first time. OFDP will play...
This paper presents a method to improve the dynamic range of white light interferometer (WLI) based polarization mode coupling (PMC) measurement system beyond 100 dB. The limitation interference beat noise is overcame by analyzing in detail inherent noises that have impacts on detection sensitivity. An improved PMC and are proposed for testing ultra-high extinction ratio (PER) polarization-related devices. can dramatically through eliminating enhancing tested intensity simultaneously, which...
Advanced chemometric analysis is required for rapid and reliable determination of physical and/or chemical components in complex gas mixtures. Based on infrared (IR) spectroscopic/sensing techniques, we propose an advanced regression model based the extreme learning machine (ELM) algorithm quantitative analysis. The proposed makes two contributions to field chemometrics. First, ELM-based autoencoder (AE) was developed reducing dimensionality spectral signals important features regression....
In this article, we present a self-calibrated absolute thickness measurement method for opaque specimens based on fiber-optic white light interferometry. A new type of self-reference probe, which is composed fiber ferrule, an integrated beam splitter, and gradient index lens, presented. our setup, two probes kind are fixed facing each other, the distance between them can be measured. Then insert specimen measure surfaces both sides. This way, realized without traditional calibration process...
We propose an ultra-simple dual-channel configuration for simultaneously evaluating two branches of a multifunctional integrated optic chip (MFIOC). In the configuration, MFIOC is employed as beam splitter to construct demodulation interferometer together with 2×2 fiber coupler. Interference happens between polarization modes traveling through different channels MFIOC. The cross-couplings each channel are respectively characterized by interference peaks which distribute on opposite sides...
Polarization extinction ratio (PER) is a quantitative indicator of the polarization-maintaining (PM) ability device. In this work, we present distributed PER measurement method based on white-light interferometry. It can accurately measure distribution PM device even in presence strong polarization crosstalk. We show that be expressed as reciprocal accumulated crosstalk along Thus, calculated from crosstalk, introduced concept induced loss to prove there significant error measured The...
Simultaneous measurement of thickness and refractive index is an important quality control scheme in high-end fabrication. However, the precise large-range still technically difficult. In this paper, we propose a high-precision simultaneous method group using differential white light interferometry. Using bi-directional interferometer with high dynamic range, can get access to optical paths on both sides specimen. We evaluate performance proposed by measuring specimens three different...
We propose an effective and promising method to extend the continuous range of optical delay line in white light interferometry. The adopts combination switchable fixed delays a continuous-scanning stage laid one arm interferometer. Moreover, fiber ring constructed by coupler is employed other achieve self-calibration improve precision, voiding use specialized measurement instrument. range-extension maintains original performances just through process orderly copying jointing. setup with 16...
We present a high-resolution polarization crosstalk measurement method for maintaining fiber (PMF) with considerable dispersion. The birefringence dispersion of the PMF severely degrades spatial resolution distributed measurement. Conventional compensation methods are effective modest coefficients (for instance, 0.0014 ps/nm/km). an iterative matched filter (IMF) to cope case measured coil coefficient 0.235 ps/nm/km. By applying IMF method, we obtained 0.09 m at any position (a maximum 12.36...
We propose a common-path interferometer (CPI) method to suppress the ambient and laser phase noise in frequency sweeping interferometry. The CPI realizes multiplexing of main auxiliary ensure common-mode characteristic interference noise, which can be eliminated by signal mixing. In experiments, we obtain dynamic range up 110 dB. Compared with compensation using separated interferometer, improves 10 dB is immune noise. proposed enables high-precision distributed polarization measurements...
We propose an envelope detrending method to correct parasitic amplitude modulation (AM) in frequency sweeping interferometry (FSI). Parasitic AM arises from effects such as device spectral response and residual of laser. The periodic component introduces spurious harmonics, which degrade the spurious-free dynamic range (SFDR) interfere with information analysis. proposed employs a Hilbert transform obtain time-varying fluctuation curve auxiliary interferometer. This is then employed detrend...
A dual Mach-Zehnder interferometer (MZI) based on polarization-maintaining fiber (PMF) is described for simultaneous measurement of displacement and temperature. Two orthogonal polarization components a beam are simultaneously transmitted in the interferometer. The sensing configuration contains short PMF section, lens, mirror. lens can transmit slow component reflect fast component. Each exhibits unique phase shift response to changes temperature, forming MZI. Experimental results show that...
The high-order interference (HOI)—The interferogram introduced by polarization mode couplings (PMC) of multiple perturbations—Will cause misjudgment the realistic coupling points in polarization-maintaining fiber (PMF) which is tested with a white light interferometer (WLI) large dynamic range. We present an optical path tracking (OPT) method for simplifying analysis HOI, and demonstrate enhancement suppression conditions HOIs. A strategy proposed to readily identify HOI altering spliced...