2020

• Record 61 of
  
  Title:Enhanced Four-Wave Mixing in Micro-Ring Resonators Integrated with Layered Graphene Oxide Films
  
  Author(s):Wu, Jiayang(1); Yang, Yunyi(1); Zhang, Yuning(1); Qu, Yang(1); Jia, Linnan(1); Xu, Xingyuan(1); Chu, Sai T.(2); Little, Brent E.(3); Morandotti, Roberto(4); Jia, Baohua(1); Moss, David J.(1)
  Source: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS  Volume: 2020-May  Issue:   DOI: null  Published: May 2020  
  Abstract:We experimentally demonstrate enhanced four-wave mixing in micro-ring resonators (MRRs) integrated with graphene oxide films. We achieve up to ∼7.6-dB enhancement in conversion efficiency for a uniformly coated MRR and ∼10.3-dB for a patterned device. © 2020 OSA.
  Accession Number: 20204009261488
• Record 62 of
  
  Title:Determination of Heavy Metal Soil Contaminants Based on Photoacoustic Spectroscopy
  
  Author(s):Liu, Lixian(1,3); Huan, Huiting(1); Zhang, Le(1); Zhao, Bingxing(2); Shao, Xiaopeng(1)
  Source: International Journal of Thermophysics  Volume: 41  Issue: 2  DOI: 10.1007/s10765-019-2599-9  Published: February 1, 2020  
  Abstract:Heavy metal (HM) contamination in soil is a threat to human health and environmental safety. This paper presents an infrared photoacoustic spectroscopic non-destructive testing for HM evaluation by a robust customized photoacoustic spectrometric system. Cadmium (Cd) was selected as the target contamination which was blended in soil samples. A two-layer feed-forward artificial neural network (ANN) model was developed for HM concentration estimation. The results show that the standard normal variate and continuum removal methods are the best preprocessing algorithms regarding the maximal correction coefficient (R2 > 0.90) and the minimal root mean square error criteria. The correction coefficient analysis shows a better prediction performance (R2 > 0.95) for a HM concentration estimation with the two preprocessing methods. In conclusion, the prediction accuracy can be significantly improved by implementing specific preprocessing and training methods. The ANN model-based infrared photoacoustic spectroscopic method has a future potential for the featureless HM contamination estimation in soil. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
  Accession Number: 20200308051794
• Record 63 of
  
  Title:Optical design of the visible telescope for the SVOM mission
  
  Author(s):Fan, Xuewu(1); Zou, Gangyi(1,2); Qiu, Yulei(3); Pang, Zhihai(1); Zhao, Hui(1); Chen, Qinfang(1); Pan, Yue(1,2); Yuan, Hao(1)
  Source: Applied Optics  Volume: 59  Issue: 10  DOI: 10.1364/AO.386177  Published: April 1, 2020  
  Abstract:This paper describes the optical design of the visible telescope (VT), which is the primary payload for the Chinese-French Space-based multi-band astronomical Variable Objects Monitor (SVOM) mission, for the detection and observation of high-redshift gamma-ray bursts. The VT aims at reaching a limiting magnitude of +22.5 Mv with the exposure time of 300 s in the 630 km Sun-synchronous orbit with an inclination of 30◦. The VT, also known as the fine guidance sensor for the SVOM, aims to measure the relative performance error (RPE) of the platform during the tracking and provide the RPE to the platform to correct its stability. The optical design is presented in this paper. The mirror manufacture and test results are presented. The optical system performance, tolerance budget, thermal analysis, and stray light design of VT are fully analyzed. Finally, the diffraction encircled energy and point source transmittance are tested in the lab for the finished telescope. © 2020 Optical Society of America.
  Accession Number: 20201508395828
• Record 64 of
  
  Title:Deep convolutional neural network phase unwrapping for fringe projection 3d imaging
  
  Author(s):Liang, Jian(1,2); Zhang, Junchao(2); Shao, Jianbo(2); Song, Bofan(2); Yao, Baoli(1); Liang, Rongguang(2)
  Source: Sensors (Switzerland)  Volume: 20  Issue: 13  DOI: 10.3390/s20133691  Published: July 2020  
  Abstract:Phase unwrapping is a very important step in fringe projection 3D imaging. In this paper, we propose a new neural network for accurate phase unwrapping to address the special needs in fringe projection 3D imaging. Instead of labeling the wrapped phase with integers directly, a two-step training process with the same network configuration is proposed. In the first step, the network (network I) is trained to label only four key features in the wrapped phase. In the second step, another network with same configuration (network II) is trained to label the wrapped phase segments. The advantages are that the dimension of the wrapped phase can be much larger from that of the training data, and the phase with serious Gaussian noise can be correctly unwrapped. We demonstrate the performance and key features of the neural network trained with the simulation data for the experimental data. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  Accession Number: 20202708904475
• Record 65 of
  
  Title:Integrated polarizers based on graphene oxide in waveguides and ring resonators
  
  Author(s):Wu, Jiayang(1); Yang, Yunyi(1); Zhang, Yuning(1); Qu, Yang(1); Xu, Xingyuan(1); Jia, Linnan(1); Liang, Yao(1); Chu, Sai T.(2); Little, Brent E.(3); Morandotti, Roberto(4,5,6); Jia, Baohua(1); Moss, David(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11282  Issue:   DOI: 10.1117/12.2544584  Published: 2020  
  Abstract:Polarization selective devices, such as polarizers and polarization selective resonant cavities (e.g., gratings and ring resonators), are core components for polarization control in optical systems and find wide applications in polarizationdivision- multiplexing, coherent optical detection, photography, liquid crystal display, and optical sensing. In this paper, we demonstrate integrated waveguide polarizers and polarization-selective micro-ring resonators (MRRs) incorporated with graphene oxide (GO). We achieve highly precise control of the placement, thickness, and length of the GO films coated on integrated photonic devices by using a solution-based, transfer-free, and layer-by-layer GO coating method followed by photolithography and lift-off processes. The latter overcomes the layer transfer fabrication limitations of 2D materials and represent a significant advance towards manufacturing integrated photonic devices incorporated with 2D materials. We measure the performance of the waveguide polarizer for different GO film thicknesses and lengths versus polarization, wavelength, and power, achieving a very high polarization dependent loss (PDL) of ∼ 53.8 dB. For GOcoated integrated MRRs, we achieve an 8.3-dB polarization extinction ratio between the TE and TM resonances, with the extracted propagation loss showing good agreement with the waveguide results. Furthermore, we present layer-by-layer characterization of the linear optical properties of 2D layered GO films, including detailed measurements that conclusively determine the material loss anisotropy of the GO films as well as the relative contribution of film loss anisotropy versus polarization-dependent mode overlap, to the device performance. These results offer interesting physical insights and trends of the layered GO films from monolayer to quasi bulk like behavior and confirm the high-performance of integrated polarization selective devices incorporated with GO films. © 2020 SPIE.
  Accession Number: 20201608478914
• Record 66 of
  
  Title:Laser Cavity Solitons and Turing Patterns in Microresonator Filtered Lasers
  
  Author(s):Pasquazi, Alessia(1); Rowley, Maxwell(1); Hazard, Pierre-Henry(1); Bao, Hualong(1); Olivieri, Luana(1); Cutrona, Antonio(1); Gongora, Juan Sebastian Totero(1); Chu, Sai T.(2); Little, Brent E.(3); Morandotti, Roberto(4); Moss, David J.(5); Oppo, Gian-Luca(6); Peccianti, Marco(1)
  Source: 2020 IEEE Photonics Conference, IPC 2020 - Proceedings  Volume:   Issue:   DOI: 10.1109/IPC47351.2020.9252327  Published: September 2020  
  Abstract:We summarise our results on the generation of temporal laser cavity-solitons and Turing patterns in a system comprising an optical micro-cavity nested in a fibre laser. We will discuss the experiments at the light of out theoretical model, commenting on their potential. © 2020 IEEE.
  Accession Number: 20205209669508
• Record 67 of
  
  Title:Online correction method for the registration error between tsmftis detector and interferogram
  
  Author(s):Cao, Jun(1); Yuan, Yan(1); Su, Lijuan(1); Zhu, Conghui(1); Yan, Qiangqiang(2)
  Source: Sensors (Switzerland)  Volume: 20  Issue: 4  DOI: 10.3390/s20041195  Published: February 2, 2020  
  Abstract:Temporally-spatially modulated Fourier transform imaging spectrometers (TSMFTISs) provide high-throughout-type push-broom spectrometry with both temporal and spatial modulation features. The system requires strict registration between the detector and the interferogram. However, registration errors are unavoidable and directly change the corresponding optical path difference values of the interferogram. As a result, the interferogram should be corrected before restoring the spectrum. In order to obtain the correct optical path difference (OPD) values, an online registration error correction method based on robust least-square linear fitting is presented. The model of the registration error was constructed to analyze its effect on the reconstructed spectra. Fitting methods were used to obtain correct optical path difference information. Simulations based on the proposed method were performed to determine the influence of the registration error on the restored spectra and the effectiveness of the proposed correction method. The simulation results prove that the accuracy of the recovered spectrum can be improved after correcting the interferogram deviation caused by the registration error. The experimental data were also corrected using the proposed methods. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  Accession Number: 20200908211139
• Record 68 of
  
  Title:Overcoming low-power limitations on optical frequency combs using a micro-ring resonator
  
  Author(s):Corcoran, Bill(1); Prayoonyong, Chawaphon(1); Boes, Andreas(2); Xu, Xingyuan(3); Tan, Mengxi(3); Chu, Sai T.(4); Little, Brent E.(5); Morandotti, Roberto(6,7); Mitchell, Arnan(2); Moss, David J.(3)
  Source: Optics InfoBase Conference Papers  Volume: Part F174-OFC 2020  Issue:   DOI: 10.1364/OFC.2020.T4G.5  Published: 2020  
  Abstract:We show that filtering of an optical frequency comb with a high quality-factor ring resonator enables the use of amplified low power combs as a multi-wavelength source. This approach improves effective source OSNR by 10 dB. OFC 2020 © OSA 2020 © 2020 The Author(s)
  Accession Number: 20203509117978
• Record 69 of
  
  Title:Overcoming Low-Power Limitations on Optical Frequency Combs using a Micro-Ring Resonator
  
  Author(s):Corcoran, Bill(1); Prayoonyong, Chawaphon(1); Boes, Andreas(2); Xu, Xingyuan(3); Tan, Mengxi(3); Chu, Sai T.(4); Little, Brent E.(5); Morandotti, Roberto(6); Mitchell, Arnan(2); Moss, David J.(3)
  Source: 2020 Optical Fiber Communications Conference and Exhibition, OFC 2020 - Proceedings  Volume:   Issue:   DOI: null  Published: March 2020  
  Abstract:We show that filtering of an optical frequency comb with a high quality-factor ring resonator enables the use of amplified low power combs as a multi-wavelength source. This approach improves effective source OSNR by 10 dB. © 2020 OSA.
  Accession Number: 20202208712412
• Record 70 of
  
  Title:Optimization and experiment of a novel compliant focusing mechanism for space remote sensor
  
  Author(s):Li, Yan(1,2); Ge, Wenjie(1); Zhang, Xu(1); Tong, Xinxing(3)
  Source: Sensors (Switzerland)  Volume: 20  Issue: 23  DOI: 10.3390/s20236826  Published: December 1, 2020  
  Abstract:The change of an external environment leads to the defocusing phenomenon of the space optical remote sensor. The performance of the focusing mechanism is related to the image quality of the remote sensor. It was optimized for a novel focusing mechanism comprised of a flexural hinge lever-type amplifier and several piezoelectric ceramics to improve the performance on high loads and large stroke in this research. It has advantages of a lightweight, simple structure and high reliability compared with the traditional focusing mechanism. The input displacement from the piezoelectric actuators was amplified by a two-stage flexure hinge lever-type mechanism. Dimensional parameters of the flexural hinges were considered as design variables. Based on the optimization ideology, reasonable compliance and dimension parameters of the flexural hinges were analyzed for the focusing mechanism. Simulation and experiments of deformation were conducted to validate the correctness of design optimization. The results show that the focusing mechanism designed by the proposed method has the capabilities of an amplification ratio of 100 times and a loading carrying capacity of 2 kg. This work provides a novel strategy to design an excellent focusing mechanism with lightweight, high loads and large stroke. Moreover, it is believed that this approach can be extended to other complex sensors. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
  Accession Number: 20204909573808
• Record 71 of
  
  Title:Ultra-high bandwidth optical data transmission with a microcomb
  
  Author(s):Tan, Mengxi(1); Corcoran, Bill(2); Xu, Xingyuan(1,2); Wu, Jiayang(1); Boes, Andreas(3); Nguyen, Thach G.(3); Chu, Sai T.(4); Little, Brent E.(5); Morandotti, Roberto(6); Mitchell, Arnan(3); Moss, David J.(1)
  Source: 2020 International Topical Meeting on Microwave Photonics, MWP 2020 - Proceedings  Volume:   Issue:   DOI: null  Published: November 24, 2020  
  Abstract:We report record data transmission over standard optical fibre using a single integrated chip source. We demonstrate a line rate of 44.2 Terabits per second (Tb/s) using the telecommunications C-band at 1550nm with a spectral efficiency - a critically important performance metric - of 10.4 bits/s/Hz. We use a new and powerful class of micro-comb called soliton crystals that exhibit robust operation and stable generation as well as a high intrinsic efficiency that, together with an extremely low spacing of 48.9 GHz enables a very high coherent data modulation format of 64 QAM. We demonstrate error free transmission over 75 km of standard optical fibre in the laboratory and a field trial over an installed metropolitan optical fiber network. This work demonstrates the capability of optical micro-combs to out-perform other approaches in demanding and practical optical communications networks. © 2020 IEICE.
  Accession Number: 20210609881374
• Record 72 of
  
  Title:Performance Evaluation of Spaceborne Atomic Clock for BDS-3 Basic System
  
  Author(s):Sun, Guang(1); Shen, Lirong(2); Zou, Tongyuan(1); Jia, Xiaolin(3); Liu, Xiaogang(3); Guo, Meijun(1); Zhai, Wei(1); Hong, Yingjie(1); Wu, Jiali(4)
  Source: Lecture Notes in Electrical Engineering  Volume: 652 LNEE  Issue:   DOI: 10.1007/978-981-15-3715-8_1  Published: 2020  
  Abstract:At present, China’s BDS-3 basic system has been completed and started to provide global services. However, the accuracy of satellite clock difference seriously restricts the service performance of BDS, and the performance of satellite atomic clock directly determines the accuracy of satellite clock difference. To solve this problem, this paper studies and evaluates the performance of BDS-3 spaceborne atomic clock in detail. Based on the precision satellite clock data of BDS from August to October 2019, using the median method, this paper pre-processed the BDS-2 and BDS-3 data, and obtained the fitting residuals of the spaceborne atomic clock by using the polynomial fitting method. In addition, in the frequency domain, this paper studied and compared the periodic characteristics of spaceborne atomic clock of BDS-3 and BDS-2. The experimental results show that all the clock difference of BDS show significant periodic characteristics, and the main period of BDS satellite clock difference is 12 h and 24 h respectively, corresponding to 0.5 times, 1 times and 2 times of each satellite orbit period. Compared with BDS-2, the main period term of BDS-3 is clearer, more accurate and more stable. In addition, the experiment also shows that the period of satellite clock difference is different in different orbits and in the same orbit the periodic term of satellite clock difference is also different. The period term of BDS-3 is consistent with that of other MEO satellites. Finally, the performance analysis of BDS atomic clock shows that the performance of BDS-3 hydrogen atomic clock is better than that of BDS-2 atomic clock. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
  Accession Number: 20202408822694