2017
2017
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Record 517 of
Title:Reconfigurable microwave photonic differentiator based on an integrated Kerr frequency comb source
Author(s):Xu, Xingyuan(1); Wu, Jiayang(1); Shoeiby, Mehrdad(2); Nguyen, Thach G.(2); Chu, Sai T.(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)Source: 2017 Opto-Electronics and Communications Conference, OECC 2017 and Photonics Global Conference, PGC 2017 Volume: 2017-November Issue: DOI: 10.1109/OECC.2017.8114872 Published: November 17, 2017Abstract:We propose and experimentally demonstrate a reconfigurable photonic RF differentiator based on a Kerr frequency comb generated in an integrated nonlinear microring resonator. The RF magnitude and phase responses are experimentally characterized. Systems demonstrations for Gaussian input signals are also performed. ? 2017 IEEE.Accession Number: 20182405305274 -
Record 518 of
Title:Integrated kerr comb-based reconfigurable transversal differentiator for microwave photonic signal processing
Author(s):Xu, Xingyuan(1); Wu, Jiayang(1); Shoeiby, Mehrdad(2); Nguyen, Thach G.(2); Chu, Sai T.(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)Source: Optics InfoBase Conference Papers Volume: Part F52-IPRSN 2017 Issue: DOI: 10.1364/IPRSN.2017.IW1A.6 Published: 2017Abstract:An integrated reconfigurable transversal differentiator is achieved based on an integrated nonlinear micro-ring resonator. The RF responses of different orders of differentiation are experimentally characterized. Systems demonstrations for Gaussian input signals are also performed. ? OSA 2017.Accession Number: 20173504083070 -
Record 519 of
Title:A generalized power iteration method for solving quadratic problem on the Stiefel manifold
Author(s):Nie, Feiping(1); Zhang, Rui(1); Li, Xuelong(2)Source: Science China Information Sciences Volume: 60 Issue: 11 DOI: 10.1007/s11432-016-9021-9 Published: November 1, 2017Abstract:In this paper, we first propose a novel generalized power iteration (GPI) method to solve the quadratic problem on the Stiefel manifold (QPSM) as minWTW=I Tr(WTAW ? 2WTB) along with the theoretical analysis. Accordingly, its special case known as the orthogonal least square regression (OLSR) is under further investigation. Based on the aforementioned studies, we then majorly focus on solving the unbalanced orthogonal procrustes problem (UOPP). As a result, not only a general convergent algorithm is derived theoretically but the efficiency of the proposed approach is verified empirically as well. ? 2017, Science China Press and Springer-Verlag Berlin Heidelberg.Accession Number: 20171903648492 -
Record 520 of
Title:Defect states emerging from a non-Hermitian flat band of photonic zero modes
Author(s):Qi, Bingkun(1,2); Zhang, Lingxuan(1,3); Ge, Li(1,2)Source: arXiv Volume: Issue: DOI: Published: April 15, 2017Abstract:We show the existence of a flat band consisting of photonic zero modes in a gain and loss modulated lattice system, as a result of the underlying non-Hermitian particle-hole symmetry. This general finding explains the previous observation in parity-time symmetric systems where non-Hermitian particle-hole symmetry is hidden. We further discuss the defect states in these systems, whose emergence can be viewed as an unconventional alignment of a pseudo-spin under the influence of a complex-valued pseudo-magnetic field. These defect states also behave as a chain with two types of links, one rigid in a unit cell and one soft between unit cells, as the defect states become increasingly localized with the gain and loss strength. Copyright ? 2017, The Authors. All rights reserved.Accession Number: 20200070477 -
Record 521 of
Title:Four-wave mixing photon pair generation statistics for a nonlinear microcavity with chaotic and pulsed excitation
Author(s):Roztocki, Piotr(1); Kues, Michael(1,2); Reimer, Christian(1); Little, Brent E.(3); Chu, Sai T.(4); Moss, David J.(1,5); Morandotti, Roberto(1,6,7)Source: Optics InfoBase Conference Papers Volume: Part F42-CLEO_QELS 2017 Issue: DOI: 10.1364/CLEO_QELS.2017.FTu4D.3 Published: 2017Abstract:We characterize four-wave mixing photon pair generation statistics in the chaotic pulsed regime associated with a self-locked nonlinear microcavity excitation scheme, and contrast these statistics against a pulsed actively mode-locked excitation. ? OSA 2017.Accession Number: 20172403771228 -
Record 522 of
Title:A passively mode-locked nanosecond laser with an ultra-narrow spectral width
Author(s):Kues, Michael(1,2); Reimer, Christian(1); Wetzel, Benjamin(1,3); Roztocki, Piotr(1); Little, Brent E.(4); Chu, Sai T.(5); Hansson, Tobias(1); Viktorov, Evgeny A.(6); Moss, David J.(1,7); Morandotti, Roberto(1)Source: Optics InfoBase Conference Papers Volume: Part F82-CLEO_Europe 2017 Issue: DOI: Published: 2017Abstract:nullAccession Number: 20180104612208 -
Record 523 of
Title:Stable and uniform multiwavelength erbium-doped fiber laser based on a microfiber knot resonator with a Sagnac loop reflector
Author(s):Xu, Yiping(1); Ren, Liyong(2); Ma, Chengju(3); Kong, Xudong(2); Ren, Kaili(2); Song, Feng(1,4)Source: Journal of Optics (India) Volume: 46 Issue: 4 DOI: 10.1007/s12596-017-0394-1 Published: December 1, 2017Abstract:In this paper, we proposed and demonstrated a stable and uniform multiwavelength erbium-doped fiber laser (EDFL) by using of the filer action of microfiber knot resonator (MKR) with a Sagnac loop reflector. By embedding the resonator to the ring cavity of the EDFL by means of a circulator, a multiwavelength EDFL is created. The number of the lasing lines with different wavelengths within 3-dB bandwidth is up to 42, the linewidth of each lasing line is about 0.05?nm and the side-mode suppression ratio is about 45?dB. The results demonstrate that the MKR with a Sagnac loop reflector can be employed as a high performance comb filter to realize a stable and uniform multiwavelength fiber laser. ? 2017, The Optical Society of India.Accession Number: 20171403539925 -
Record 524 of
Title:Numerical simulation and temporal characterization of dual-pumped microring-resonator-based optical frequency combs
Author(s):Hu, Xiaohong(1,2); Wang, Weiqiang(1,2,3); Wang, Leiran(1,2); Zhang, Wenfu(1,2,3); Wang, Yishan(1); Zhao, Wei(1)Source: Photonics Research Volume: 5 Issue: 3 DOI: 10.1364/PRJ.5.000207 Published: June 1, 2017Abstract:Dual-pumped microring-resonator-based optical frequency combs (OFCs) and their temporal characteristics are numerically investigated and experimentally explored. The calculation results obtained by solving the driven and damped nonlinear Schr?dinger equation indicate that an ultralow coupled pump power is required to excite the primary comb modes through a non-degenerate four-wave-mixing (FWM) process and, when the pump power is boosted, both the comb mode intensities and spectral bandwidths increase. At low pump powers, the field intensity profile exhibits a cosine variation manner with frequency equal to the separation of the two pumps, while a roll Turing pattern is formed resulting from the increased comb mode intensities and spectral bandwidths at high pump powers. Meanwhile, we found that the power difference between the two pump fields can be transferred to the newly generated comb modes, which are located on both sides of the pump modes, through a cascaded FWM process. Experimentally, the dual-pumped OFCs were realized by coupling two self-oscillating pump fields into a microring resonator. The numerically calculated comb spectrum is verified by generating an OFC with 2.0 THz mode spacing over 160 nm bandwidth. In addition, the formation of a roll Turing pattern at high pump powers is inferred from the measured autocorrelation trace of a 10 free spectral range (FSR) OFC. The experimental observations accord well with the numerical predictions. Due to their large and tunable mode spacing, robustness, and flexibility, the proposed dual-pumped OFCs could find potential applications in a wide range of fields, including arbitrary optical waveform generation, high-capacity optical communications, and signal-processing systems. ? 2017 Chinese Laser Press.Accession Number: 20182705409253 -
Record 525 of
Title:A markerless visual-motor tracking system for behavior monitoring in DCD assessment
Author(s):Li, Shengyan(1); Li, Bin(1,2); Zhang, Shixiong(1); Fu, Hong(1); Lo, Wai-Lun(1); Yu, Jie(3); Sit, Cindy H. P.(3); Li, Ruimin(1,2)Source: Proceedings - 9th Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, APSIPA ASC 2017 Volume: 2018-February Issue: DOI: 10.1109/APSIPA.2017.8282139 Published: July 2, 2017Abstract:Development coordination disorder (DCD) is a disorder of visual-motor integration in children, so the study on coordination of vision and motion is essential to understand the mechanism of DCD. The standardized assessments with certain visual-motor tasks are often used to detect impairments in eye-motion coordination, which is the most important component for diagnosis of DCD. However, these assessments emphasize on motor performance of children, while ignoring the detailed process of eye-motion coordination in performing these tasks. Therefore, it is a need to develop a proper digital visual-motor system to detect the eye movement and body motion simultaneously during these tasks, to study the mechanism of a typical eye-motion coordination. Currently, the eye-motion system is based on marker to detect the joints and gaze points for integration. This kind of system is very expensive and the markers may affect children's behavior in the task of DCD assessment. In this study, an integrated and markerless eye-motion system is developed to detect children's behavior in DCD assessment. In this system, a multi-Kinect system is used to monitor body motion and extract the skeletal joints. The gaze point is detected by a head-mount eye tracker and will be integrated into the system of body motion using image processing method. With the proposed system, the skeletal joints and gaze points can be obtained simultaneously for further digital DCD assessment. ? 2017 IEEE.Accession Number: 20183105646934 -
Record 526 of
Title:High Verdet constants and diamagnetic responses of GeS2-In2S3-PbI2 chalcogenide glasses for integrated optics applications
Author(s):Xu, Yantao(1,2); Guo, Haitao(1); Xiao, Xusheng(1,2); Wang, Pengfei(1); Cui, Xiaoxia(1); Lu, Min(1); Lin, Changgui(3); Dai, Shixun(3); Peng, Bo(1)Source: Optics Express Volume: 25 Issue: 17 DOI: 10.1364/OE.25.020410 Published: August 21, 2017Abstract:Chalcogenide glasses as kind of diamagnetic magneto-optical materials have promising applications in the field of integrated optics and optical communication systems due to their excellent properties, such as easy to be processed into waveguide and temperature independence of the Verdet constants. For clarifying the influence factors following the compositional variation on Faraday effect and finding a glass with a large Verdet constant, novel pseudo-ternary chalcogenide glass system, GeS2 - In2S3 - PbI2, was prepared and investigated. The composition, wavelength and temperature dependences on the Verdet constants were systematically investigated at the wavelengths of 635, 808, 980 and 1319 nm. PbI2 was confirmed to have positive contribution to the Verdet constant and the Becquerel rule was proved to be an effective guidance for predicting the Verdet constant in chalcogenide glasses. The 60GeS2·15In2S3·25PbI2 glass was found to possess the largest Verdet constant (V = 0.215 min·G?1·cm?1, @808nm), which is great larger than that of commercial diamagnetic glasses. These glasses also possess good glass-forming ability and VIS-IR transmittance, therefore be a good candidate for next-generation integrated optical isolator and other magneto-optical devices. ? 2017 Optical Society of America.Accession Number: 20194007490055 -
Record 527 of
Title:An ultra-narrow spectral width passively mode-locked laser
Author(s):Kues, Michael(1,2); Reimer, Christian(1); Wetzel, Benjamin(1,3); Roztocki, Piotr(1); Little, Brent E.(4); Chu, Sai T.(5); Hansson, Tobias(1); Viktorov, Evgeny A.(6); Moss, David J.(1,7); Morandotti, Roberto(1)Source: 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings Volume: 2017-January Issue: DOI: 10.1364/CLEO_AT.2017.FW4D.2 Published: October 25, 2017Abstract:We demonstrate a passively mode-locked laser emitting 4.3 nanosecond Fourier-limited pulses with a record low spectral bandwidth of 104.9 MHz (more than 100 times narrower than previous realizations), allowing its full characterization in the radio-frequency domain. ? 2017 IEEE.Accession Number: 20181204933222 -
Record 528 of
Title:Single shot, three-dimensional fluorescence microscopy with a spatially rotating point spread function
Author(s):Wang, Zhaojun(1,2); Cai, Yanan(1,2); Liang, Yansheng(1,2); Zhou, Xing(1,2); Yan, Shaohui(1); Dan, Dan(1); Bianco, Piero R.(3); Lei, Ming(1); Yao, Baoli(1)Source: Biomedical Optics Express Volume: 8 Issue: 12 DOI: 10.1364/BOE.8.005493 Published: December 1, 2017Abstract:A wide-field fluorescence microscope with a double-helix point spread function (PSF) is constructed to obtain the specimen’s three-dimensional distribution with a single snapshot. Spiral-phase-based computer-generated holograms (CGHs) are adopted to make the depth-of-field of the microscope adjustable. The impact of system aberrations on the double-helix PSF at high numerical aperture is analyzed to reveal the necessity of the aberration correction. A modified cepstrum-based reconstruction scheme is promoted in accordance with properties of the new double-helix PSF. The extended depth-of-field images and the corresponding depth maps for both a simulated sample and a tilted section slice of bovine pulmonary artery endothelial (BPAE) cells are recovered, respectively, verifying that the depth-of-field is properly extended and the depth of the specimen can be estimated at a precision of 23.4nm. This three-dimensional fluorescence microscope with a framerate-rank time resolution is suitable for studying the fast developing process of thin and sparsely distributed micron-scale cells in extended depth-of-field. ? 2017 Optical Society of America.Accession Number: 20175004522978