2022

• Record 397 of
  
  Title:Mid-Infrared Graphene/Silicon-Based Electro-Optic Phase Modulator
  
  Author(s):Ban, Xiaoqiang(1,2,3); Dong, Bo(1); Chen, Zongyu(1); Huang, Wobin(1); Zhong, Ming(4); Little, Brent E.(2,3)
  Source: SSRN  Volume:   Issue:   DOI: 10.2139/ssrn.4171618  Published: July 25, 2022  
  Abstract:Electro-optic modulator plays an important role in optical signal processing. We demonstrated a low loss graphene/silicon-waveguide-based electro-optic phase modulator. The results demonstrate that the modulation efficiency increases when increasing the graphene layer and modulating length in mid-infrared region. Its 3 dB bandwidth (41.2 GHz) does not depend on the graphene modulating length. The two-layer graphene/silicon waveguide modulator can reach π phase shift with minimum insertion loss (0.05 dB) when the modulation length is 400 μm. This work is useful for designing a high-performance phase modulator. © 2022, The Authors. All rights reserved.
  Accession Number: 20220299011
• Record 398 of
  
  Title:Non-invasive Sleep-Wake Discrimination Using LS-CPC Algorithm Based on MZI-BCG Sensor
  
  Author(s):Feng, Yifei(1); Xu, Wei(2); He, Ying(1); Ge, Qinggang(3); Yang, Yilong(1)
  Source: ICOCN 2022 - 20th International Conference on Optical Communications and Networks  Volume:   Issue:   DOI: 10.1109/ICOCN55511.2022.9901061  Published: 2022  
  Abstract:A non-invasive sleep-wake discrimination algorithm based on Mach-Zehnder interferometer (MZI) assisted ballistocardiogram (BCG) sensor is proposed. According to the Lomb-Scargle (LS) periodogram and cardiopulmonary coupling (CPC) algorithm using heart rate variability and respiratory signal, the sleep-wake status could be successfully classified. © 2022 IEEE.
  Accession Number: 20224513060396
• Record 399 of
  
  Title:Unsupervised Balanced Hash Codes Learning With Multichannel Feature Fusion
  
  Author(s):Chen, Yaxiong(1); Zhao, Dongjie(1); Lu, Xiongbo(1); Xiong, Shengwu(1); Wang, Huangting(2)
  Source: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing  Volume: 15  Issue:   DOI: 10.1109/JSTARS.2022.3162251  Published: 2022  
  Abstract:Unsupervised hashingalgorithms are widely used in large-scale remote sensing images (RSIs) retrieval task. However, existing RSI retrieval algorithms fail to capture the multichannel characteristic of multispectral RSIs and the balanced property of hash codes, which lead the poor performance of RSI retrieval. To tackle these issues, we develop an unsupervised hashing algorithm, namely, variational autoencoder balanced hashing (VABH), to leverage multichannel feature fusion and multiscale context information to perform RSI retrieval task. First, multichannel feature fusion module is designed to extract RSI feature information by leveraging the multichannel properties of multispectral RSI. Second, multiscale learning module is developed to learn the multiscale context information of RSIs. Finally, a novel objective function is designed to capture the discrimination and balanced property of hash codes in the hashing learning process. Comprehensive experiments on diverse benchmark have well demonstrated the reasonableness and effectiveness of the proposed VABH algorithm. © 2008-2012 IEEE.
  Accession Number: 20221812063181
• Record 400 of
  
  Title:Direct Modulation RZ-DPSK Signal Generation Technology Based on Chirp-Managed Lasers
  
  Author(s):Ma, Rong(1,2,3); Gao, Duorui(1,2,3); Wei, Sentao(1,2); Xie, Zhuang(1,2,3); Wang, Wei(1,2); Jia, Shuaiwei(1,2,3); Bai, Zhaofeng(1,2); Xie, Xiaoping(1,2,3)
  Source: Zhongguo Jiguang/Chinese Journal of Lasers  Volume: 49  Issue: 13  DOI: 10.3788/CJL202249.1306001  Published: July 2022  
  Abstract:Objective Due to its bandwidth advantage space laser communication has become an effective means to solve the bottleneck of microwave communication build a space-based broadband network and realize the real-time transmission of massive amount of earth observation data The space laser communication terminal has characteristics of small size lightweight low power consumption etc which are suitable for satellite payload and meet the increasing communication needs of aerospace activities In future each communication satellite will carry multiple laser communication terminals that can serve multiple targets simultaneously Therefore laser communication terminals are being developed in the direction of miniaturization and integration Traditional laser communication terminals use external modulation methods to achieve intensity or phase modulation of optical signals Optical transmitters comprise multiple independent components such as lasers modulators and bias controllers and the system's structure is complex The phase modulation of the optical signal is realized using the direct modulation of the chirp-managed laser CML without an external modulator bias controller etc with small size low power consumption low equipment complexity and low cost In addition it can adapt to the continuous high-speed and integrated development of optical communication networks Methods In this study the chirp effect of the CML is used for phase modulation to generate a return-to-zero differential phase shift keying RZ-DPSK signal RZ-DPSK has several advantages such as high sensitivity good reliability simple receiver and its receiving sensitivity is 3 dB higher than that of on-off keying OOK modulation method It has received extensive attention in the engineering field Using the chirp effect of the laser the phase shift of the optical field is achieved by controlling the magnitude of the injected current and the driving signal is simply pre-encoded using MATLAB to generate a three-level signal thereby accurately controlling the phase change of the carrier signal The error rate performance of RZ-DPSK estimated using this modulation method was tested and compared with that of the traditional external modulation method The performance difference between the two methods was analyzed Results and Discussions This study first uses the binary sequence 1110100 to verify the system principle The schematic of the transmitter and receiver experimental schemes are shown in Figures 3 and 7 and the signal rate is 2 5 Gb s The output wavelength of the CML laser is 1552 544 nm and the output optical power is 9 14 dBm The receiving end includes erbium-doped fiber amplifier EDFA optical filter optical delay interferometer and balanced detector to receive and demodulate RZ-DPSK optical signal and restore the baseband electrical signal To further reduce the spontaneous radiation noise caused by the amplification process an optical filter with a bandwidth of 0 05 nm is placed after the EDFA The signal waveform after demodulation is shown in Figure 8 27-1 pseudo-random binary sequence PRBS is used for bit error rate test The pseudo-random signal is demodulated by the delay interferometer and the output signal eye diagram of the balanced detector is shown in Figure 9 As a comparative experiment the receiving end based on LiNbO3 external modulation and the CML system use the same receiving device The schematic of the two systems is shown in Figure 10 The bit error rate curves of RZ-DPSK system based on CML transmitter and LiNbO3 transmitter are shown in the Figure 11 When the system error rate is 10-9 the receiving sensitivity of CML and LiNbO3 transmitters is -36 98 and -45 72 dBm respectively Compared with the LiNbO3 transmitter the sensitivity of the CML system is reduced by 8 74 dB When the error rate of the forward error correction limit is 10-3 the sensitivity of the CML transmitter is -48 1 dBm which is only 1 8 dB less than the -49 9 dBm of the LiNbO3 transmitter The error characteristics of the two are the same and thus an error-free transmission can be realized The CML transmitter has a simple structure small size and low power consumption and the performance of the receiver is equivalent to that of external modulation when the limit error rate of the forward error correction is 10-3 which shows a significant development prospect Conclusions This study introduces the principle of signal coding and modulation of CML laser and realizes the direct modulation of 2 5 Gb s RZ-DPSK signal based on the CML laser without differential coding and external modulator The performance index of the modulation signal is analyzed At the same time the bit error rate performance of the transmission system based on the CML laser and the system based on the LiNbO3 transmitter are compared The results show that the sensitivity of the transmitter based on the CML is -48 1 dBm when the limit bit error rate of forward error correction is 10-3 Compared with the sensitivity of LiNbO3-based transmitter system -49 9 dBm the difference of the sensitivity of CML-based transmitter system is only 1 8 dB and the error characteristics are basically the same Further the CML-based transmitter system has a good transmission performance In terms of hardware the CML-based transmitter system has a simpler structure low power consumption small size and lightweight which can better adapt to the continuous high-speed and integrated development of space optical communication networks. © 2022 Science Press. All rights reserved.
  Accession Number: 20223212536989
• Record 401 of
  
  Title:Component spectra extraction and quantitative analysis for preservative mixtures by combining terahertz spectroscopy and machine learning
  
  Author(s):Yan, Hui(1,2,3); Fan, Wenhui(1,3,4); Chen, Xu(1); Wang, Hanqi(1,3); Qin, Chong(1,3); Jiang, Xiaoqiang(1,3)
  Source: Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy  Volume: 271  Issue:   DOI: 10.1016/j.saa.2022.120908  Published: April 15, 2022  
  Abstract:Preservatives are universally used in synergistic combination to enhance antimicrobial effect. Identify compositions and quantify components of preservatives are crucial steps in quality monitoring to guarantee merchandise safety. In the work, three most common preservatives, sorbic acid, potassium sorbate and sodium benzoate, are deliberately mixed in pairs with different mass ratios, which are supposed to be the "unknown" multicomponent systems and measured by terahertz (THz) time-domain spectroscopy. Subsequently, three major challenges have been accomplished by machine learning methods in this work. The singular value decomposition (SVD) effectively obtains the number of components in mixed preservatives. Then, the component spectra are successfully extracted by non-negative matrix factorization (NMF) and self-modeling mixture analysis (SMMA), which match well with the measured THz spectra of pure reagents. Moreover, the support vector machine for regression (SVR) designed an underlying model to the target components and simultaneously identify contents of each individual component in validation mixtures with decision coefficient R2 = 0.989. By taking advantages of the fingerprint-based THz technique and machine learning methods, our approach has been demonstrated the great potential to be served as a useful strategy for detecting preservative mixtures in practical applications. © 2022 Elsevier B.V.
  Accession Number: 20220411507549
• Record 402 of
  
  Title:Ultrasensitive fiber-based gas pressure sensor based on harmonic Vernier effect with enhanced contrast
  
  Author(s):Luo, Chunhui(1); Chen, Xiaoxu(1); Wu, Shun(1,2)
  Source: Optics and Laser Technology  Volume: 156  Issue:   DOI: 10.1016/j.optlastec.2022.108532  Published: December 2022  
  Abstract:We propose and experimentally demonstrate a highly sensitive gas pressure sensor in parallel configuration based on harmonic Vernier effect. The sensor consists of two segments of 75 μm hollow-core capillaries as the sensing and reference Fabry Perot cavity. An open passage is formed by a 5 μm capillary in the sensing cavity while the reference cavity is sealed by a single-mode fiber. A pressure sensitivity of 279.52 pm/kPa is achieved. Our scheme uses "air" instead of "silica" reference cavity, which allows higher sensitivity for a given accuracy of cavity length control. In addition, we also developed a "superposition envelope" method, which improves the contrast by at least 3 dB for the Vernier envelope. This design for high-sensitivity optic fiber gas sensor can be a good candidate for ultrasensitive gas pressure applications. © 2022 Elsevier Ltd
  Accession Number: 20223212534869
• Record 403 of
  
  Title:Phase image correlation spectroscopy for detecting microfluidic dynamics
  
  Author(s):Yu, Lan(1); Wang, Yu(1); Wang, Yang(1); Zhuo, Kequn(1); Ma, Ying(1); Liu, Min(1); Zheng, Juanjuan(1,2); Li, Jianlang(1); Li, Junhua(3); Gao, Peng(1)
  Source: Applied Optics  Volume: 61  Issue: 20  DOI: 10.1364/AO.458026  Published: July 10, 2022  
  Abstract:It is essential to quantify the physical properties and the dynamics of flowing particles in many fields, especially in microfluidic-related applications. We propose phase image correlation spectroscopy (PICS) as a versatile tool to quantify the concentration, hydro-diameter, and flow velocity of unlabeled particles by correlating the pixels of the phase images taken on flowing particles in a microfluidic device. Compared with conventional image correlation spectroscopy, PICS is minimally invasive, relatively simple, and more efficient, since it utilizes the intrinsic phase of the particles to provide a contrast instead of fluorescent labeling. We demonstrate the feasibility of PICS by measuring flowing polymethylmethacrylate (PMMA) microspheres and yeast in a microfluidic device. We can envisage that PICS will become an essential inspection tool in biomedicine and industry. © 2022 Optica Publishing Group
  Accession Number: 20222812345476
• Record 404 of
  
  Title:Localized modes in nonlinear fractional systems with deep lattices
  
  Author(s):Liu, Xiuye(1,2); Malomed, Boris A.(3,4,5); Zeng, Jianhua(1,2)
  Source: arXiv  Volume:   Issue:   DOI:   Published: January 4, 2022  
  Abstract:Solitons in the fractional space, supported by lattice potentials, have recently attracted much interest. We consider the limit of deep one-and two-dimensional (1D and 2D) lattices in this system, featuring finite bandgaps separated by nearly flat Bloch bands. Such spectra are also a subject of great interest in current studies. The existence, shapes, and stability of various localized modes, including fundamental gap and vortex solitons, are investigated by means of numerical methods; some results are also obtained with the help of analytical approximations. In particular, the 1D and 2D gap solitons, belonging to the first and second finite bandgaps, are tightly confined around a single cell of the deep lattice. Vortex gap solitons are constructed as four-peak "squares" and "rhombuses" with imprinted winding number S = 1. Stability of the solitons is explored by means of the linearization and verified by direct simulations. Copyright © 2022, The Authors. All rights reserved.
  Accession Number: 20220005731
• Record 405 of
  
  Title:Design of continuous zoom TV detection system in deep-sea
  
  Author(s):Peng, Jianwei(1); Zhang, Gaopeng(1); Chen, Weining(1); Dong, Sen(1); Yang, Hongtao(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12166  Issue:   DOI: 10.1117/12.2614623  Published: 2022  
  Abstract:In order to meet the needs of TV detection in deep sea environment, a compact continuous zoom system driven by cam sleeve is studied. Through the analysis of the system indicators, the optical system of three groups of linkage zoom and rear group for focusing is selected, and the structure of cylindrical cam driving to cooperate with the cylindrical guide sliding is clarified. Based on this idea, each module of the TV detection system is designed in detail. The design method of electric iris diaphragm in the middle of the system is proposed, and the calculation process and results of zoom drive mechanism selection are given. The method of alignment of lens optical axis adjustment with theodolite and cross-reticle is put forward. With this design and adjustment process, the TV detection system can be applied to deep sea environment is finally realized. The system has a continuously variable field of view with 5.8°∼60° underwater, the F number changes from 3.5 to 16, and the whole zoom time is less than 2s. The test results show that the MTF of the center field of view at the long focal point and the short focal point are 0.4 and 0.57. Test images in laboratory and underwater scene are clear and high resolution, which shows that the imaging quality of the system is excellent. At the same time, the system is Φ 105×115mm in actual size and 860g in weight, and can be integrated into the deep-sea pressure cabin to meet the needs of deep-sea detection. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20220911734828
• Record 406 of
  
  Title:Modulator-Free Variable Multi-Rate FSO Communication 1 km Outfield Demonstration Based on Chirp-Managed Laser
  
  Author(s):Xie, Zhuang(1,2); Jia, Shuaiwei(1,2); Shao, Wen(1,2); Wang, Yang(1,2); Ma, Rong(1); Wei, Sentao(1); Liao, Peixuan(1,3); Zhang, Dongquan(1); Wang, Weiqiang(1); Gao, Duorui(1,3); Wang, Wei(1); Xie, Xiaoping(1,2)
  Source: IEEE Photonics Journal  Volume: 14  Issue: 6  DOI: 10.1109/JPHOT.2022.3211268  Published: December 1, 2022  
  Abstract:Due to the high energy efficiency per bit and high sensitivity, Return-to-zero differential-phase-shift-keying (RZ-DPSK) is perfectly suitable for free-space laser communications. However, the conventional generation method of RZ-DPSK optical signal requires two modulators, which is costly, bulky, and heavy, significantly hindering the application of RZ-DPSK in size, weight, and power (SWaP)-constrained satellite platforms. In this paper, we propose and experimentally demonstrate a modulator-free variable multi-rate RZ-DPSK free-space optical (FSO) communication system based on chirp-managed laser (CML). Based on the proposed scheme, an FSO outfield experiment over 1 km has been successfully undertaken, achieving receiving sensitivities of-48.9 dBm and-45.6 dBm at 2.5 Gbps and 5 Gbps, with bit error rate (BER) of 1 × 10-3 without forward error correction (FEC), respectively. The performance of the proposed system is also investigated by studying the eye diagrams under two different test conditions of back-to-back transmission and 1-km free space transmission. In addition to the small size, lightweight and low cost, the proposed scheme shows great potential for a variety of FSO communication applications ranging from Cube-Star to larger satellite laser communication platforms. © 2009-2012 IEEE.
  Accession Number: 20224212979883
• Record 407 of
  
  Title:Research on distributed space objects detection technology based on optical fiber image bundles
  
  Author(s):Wang, Huawei(1); Ma, Yingjun(1); Liao, Jiawen(1); Gao, Bo(1); Fang, Yao(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12169  Issue:   DOI: 10.1117/12.2624984  Published: 2022  
  Abstract:With the rapid increase of the number of spacecrafts, the space environment is becoming more and more complex. The demand of spacecraft for omni-directional detection of surrounding objects is becoming more and more urgent. This paper introduces a distributed space objects detection technology based on optical fiber image bundles. The system adopts multi aperture optical system. The optical signal is transmitted to the high-sensitivity image sensor through the fiber image bundle for imaging. Compared with the traditional method, the multi aperture optical system using fiber image bundles can be flexibly arranged according to the needs. The system has the advantages of wide field of view, flexible layout and low cost. This paper introduces the relevant technologies used and the principle prototype developed. © 2022 SPIE
  Accession Number: 20221611967368
• Record 408 of
  
  Title:Intense 2.85 μm mid-infrared emissions in Yb3+/Ho3+ codoped and Yb3+/Er3+/Ho3+ tridoped TBLL fluorotellurite glasses and their energy transfer mechanism
  
  Author(s):Liu, Chengzhen(1,2); Feng, Shaohua(1,2); Xiao, Xusheng(1,2); Xu, Yantao(1); Guo, Haitao(1,2)
  Source: Ceramics International  Volume: 48  Issue: 4  DOI: 10.1016/j.ceramint.2021.11.068  Published: February 15, 2022  
  Abstract:Yb3+/Ho3+ codoped and Yb3+/Er3+/Ho3+ tridoped TeO2–BaF2–LaF3–La2O3 (TBLL) fluorotellurite glasses with low OH− absorption (0.026 cm-1), high glass transition temperature (434 °C) and low phonon energy (784 cm-1) were prepared. Their mid-infrared fluorescence properties and related energy transfer (ET) mechanism were studied under 980 nm excitation. A strong emission at 2.85 μm was realized in Yb3+/Ho3+ codoped tellurite glass, which was attributed to the high-efficiency ET from Yb3+ ions to Ho3+, and the ET efficiency was 91.1%. Further introduction of Er3+ ions induced stronger 2.85 μm emission, and the ET efficiency was improved to 96.2%, ascribed to the establishment of more ET channels and Er3+ ions playing the role of ET bridge between Yb3+ and Ho3+ ions. These results indicate that the Yb3+/Er3+/Ho3+ tridoped tellurite glass could be a hopeful gain medium material for the ∼3 μm fiber laser. © 2021
  Accession Number: 20214611165911