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John D Downie, Jason Hurley, Hector DePedro, Steven Garner, Jeremy Blaker, Aramais Zakharian, Sergey Ten, Greg Mills
Transmission below the cable cut-off wavelength may be a concern in some systems, especially for an optical supervisory channel (OSC) operating below the signal transmission band in systems built with G.654 fiber. In this work, we constructed a cabled span of G.654-compliant fiber and measured the multipath interference (MPI) generated during propagation through the span at a range of wavelengths below the cable cut-offs of the constituent fibers. Measurements were made under a range of conditions including different splice losses and the presence or absence of higher order mode filters placed around the splices...
April 17, 2017: Optics Express
F Mariani, F de León-Pérez, K J A Vendel, L Martín-Moreno, M P Van Exter
We present the first angle resolved measurements of extraordinary optical transmission (EOT) through hole array gratings in a gold film. Varying the lattice spacing of the arrays and looking at higher diffraction orders, we retrieve the angular emission pattern of the constituent holes with better signal to noise ratio than with single-hole experiments. We present a method to determine separately the angular dependence of the direct and resonant contribution to EOT by using the spectral features of the diffraction orders together with an established model...
April 17, 2017: Optics Express
Helen D Ford, Ralph P Tatam
Duct-profiling in test samples up to 25 mm in diameter has been demonstrated using a passive, low-coherence probe head with a depth resolution of 7.8 μm, incorporating an optical-fibre-linked conical mirror addressed by a custom-built array of single-mode fibres. Zemax modelling, and experimental assessment of instrument performance, show that degradation of focus, resulting from astigmatism introduced by the conical mirror, is mitigated by the introduction of a novel lens element. This enables a good beam focus to be achieved at distances of tens of millimetres from the cone axis, not achievable when the cone is used alone...
April 17, 2017: Optics Express
Lu Yin, Mingjian Yan, Zhigang Han, Hailin Wang, Hua Shen, Rihong Zhu
We present the segmented corrosion method that uses hydrofluoric acid to etch the fiber of a fiber laser for removing high-power cladding light to improve stripping uniformity and power handling capability. For theoretical guidelines, we propose a simulation model of etched-fiber stripping to evaluate the relationship between the etched-fiber parameters and cladding light attenuation and to analyze the stripping uniformity achieved with segmented corrosion. A two-segment etched fiber is fabricated with cladding light attenuation of 19...
April 17, 2017: Optics Express
Di Che, Feng Yuan, William Shieh
Semiconductor lasers are versatile optical transmitters in nature. Through the direct modulation (DM), the intensity modulation is realized by the linear mapping between the injection current and the light power, while various angle modulations are enabled by the frequency chirp. Limited by the direct detection, DM lasers used to be exploited only as 1-D (intensity or angle) transmitters by suppressing or simply ignoring the other modulation. Nevertheless, through the digital coherent detection, simultaneous intensity and angle modulations (namely, 2-D complex DM, CDM) can be realized by a single laser diode...
April 17, 2017: Optics Express
G V S S Praneeth Varma, Rayapati Sushma, Vandana Sharma, Abhinav Kumar, G V V Sharma
In this paper, a simple heuristic power allocation scheme is proposed for a random LED array to obtain uniform irradiance on the projection surface. This is done by considering a binomial point process (BPP) for modeling the LED location and using the quality factor as a performance metric. Numerical results are provided to validate the proposed model and demonstrate its simplicity over existing LED geometries.
April 17, 2017: Optics Express
Jie You, Nicolae C Panoiu
A computational approach to evaluate the bit-error ratio (BER) in silicon photonic systems employing high-order phase-shift keying (PSK) modulation formats is presented. Specifically, the investigated systems contain a silicon based optical interconnect, namely a strip silicon photonic waveguide or a silicon photonic crystal waveguide, and direct-detection receivers suitable to detect PSK and amplitude-shaped PSK signals. The superposition of a PSK signal and complex additive white Gaussian noise passes through the optical interconnect and subsequently through two detection-branch receivers...
April 17, 2017: Optics Express
Benjamin Crooke, Lachlan I W McKinna, Ivona Cetinić
Fowler's Sneaker Depth (FSD), analogous to the well known Secchi disk depth (Zsd), is a visually discerned citizen scientist metric used to assess water clarity in the Patuxent River estuary. In this study, a simple remote sensing algorithm was developed to derive FSD from space-borne spectroradiometric imagery. An empirical model was formed that estimates FSD from red-end remote sensing reflectances at 645 nm, Rrs(645). The model is based on a hyperbolic function relating water clarity to Rrs(645) that was established using radiative transfer modeling and fine tuned using in-water FSD measurements and coincident Rrs(645) data observed by NASA's Moderate Resolution Imaging Spectroradiometer aboard the Aqua spacecraft (MODISA)...
April 17, 2017: Optics Express
Wenye Hu, Wendy Davis
To capitalise on the colour tuning capabilities of LED lighting, a model for converting device-specific control signals to chromaticity coordinates was used in a psychophysical experiment evaluating the usability of three colour control interfaces based on RGB (red, green, blue), HSB (hue, saturation, brightness) and opponent colour mixing systems. Although common and well accepted, the RGB interface had lowest usability based on both psychophysical results and subjective ratings. The usability of HSB and opponent colour interfaces was not significantly different...
April 17, 2017: Optics Express
Haejun Chung, Xingshu Sun, Aditya D Mohite, Rahul Singh, Lokendra Kumar, Muhammad A Alam, Peter Bermel
A key challenge in photovoltaics today is to develop cell technologies with both higher efficiencies and lower fabrication costs than incumbent crystalline silicon (c-Si) single-junction cells. While tandem cells have higher efficiencies than c-Si alone, it is generally challenging to find a low-cost, high-performance material to pair with c-Si. However, the recent emergence of 22% efficient perovskite photovoltaics has created a tremendous opportunity for high-performance, low-cost perovskite / crystalline silicon tandem photovoltaic cells...
April 17, 2017: Optics Express
Peng-Wang Zhai, Yongxiang Hu, David M Winker, Bryan A Franz, Jeremy Werdell, Emmanuel Boss
Inelastic scattering plays an important role in ocean optics. The main inelastic scattering mechanisms include Raman scattering, fluorescence by colored dissolved organic matter (FDOM), and fluorescence by chlorophyll. This paper reports an implementation of all three inelastic scattering mechanisms in the exact vector radiative transfer model for coupled atmosphere and ocean Systems (CAOS). Simulation shows that FDOM contributes to the water radiation field in the broad visible spectral region, while chlorophyll fluorescence is limited in a narrow band centered at 685 nm...
April 17, 2017: Optics Express
Xiaofan Zhao, Zining Yang, Weihong Hua, Hongyan Wang, Xiaojun Xu
Although the diode pumped alkali laser (DPAL) works in a three-level scheme, higher energy-state excitation and ionization processes exist during operation, which may lead to deleterious effects on laser performance. In this paper, we report the ionization degree measurement in the gain medium of an operational hydrocarbon-free Rb DPAL by using the optogalvanic method. The results show that, at the pulsed mode with a duration of ~1 ms, a maximal ionization degree of ~0.06% is obtained at a pump power of 140 W...
April 17, 2017: Optics Express
Wei Xiong, Guangzong Xiao, Xiang Han, Jinhua Zhou, Xinlin Chen, Hui Luo
In optical traps the position of a trapped bead is usually determined by measuring the intensity distribution of the forward-scattered light and the back-scattered light. In this paper we demonstrate that this position can be determined using the side-scattered light. A quadrant photodiode is used to monitor the position of an optically trapped object in a dual-beam fiber-optic trap by measurement of intensity shifts in the back focal plane of the objective that is perpendicular to the propagating beam. An approximated model based on ray optics is presented with numerical results that describe the use of the side-scattered light for position detection...
April 17, 2017: Optics Express
Bo Meng, Wenxiang Cong, Yan Xi, Bruno De Man, Jian Yang, Ge Wang
Contrast-enhanced computed tomography (CECT) helps enhance the visibility for tumor imaging. When a high-Z contrast agent interacts with X-rays across its K-edge, X-ray photoelectric absorption would experience a sudden increment, resulting in a significant difference of the X-ray transmission intensity between the left and right energy windows of the K-edge. Using photon-counting detectors, the X-ray intensity data in the left and right windows of the K-edge can be measured simultaneously. The differential information of the two kinds of intensity data reflects the contrast-agent concentration distribution...
April 17, 2017: Optics Express
Sylvain Pinet, Jean-Michel Martinez, Sylvain Ouillon, Bruno Lartiges, Raul Espinoza Villar
We investigated the relationships between inherent and apparent optical properties (IOP and AOP, respectively) and suspended sediment concentrations (SSC) in the main Amazonian river waters. In situ measurements of SSC, remote sensing reflectance (R<sub>rs</sub>), the diffuse light attenuation coefficient (K<sub>d</sub>) and the total and non-algal particle (NAP) absorption coefficients (a<sub>TOT</sub> and a<sub>NAP</sub>, respectively) were conducted during three sampling trips along different streams of the Amazon River catchment (104 stations)...
April 17, 2017: Optics Express
Xin-Hao Li, Jeffrey B Chou, Wei Lek Kwan, Asma M Elsharif, Sang-Gook Kim
We recently reported that an Au/TiO<sub>2</sub> photonic crystal device for photochemical energy conversion showed a sub-bandgap photoresponse centered at the surface plasmon polariton (SPP) resonant wavelength of this device. Here we developed a theoretical modeling of the internal photoemission in this device by incorporating the effects of anisotropic hot electron momentum distribution caused by SPP. The influences of interband and intraband transition, anisotropic momentum distribution of hot electrons by SPP are integrated to model the internal quantum efficiency (IQE) of this device...
April 17, 2017: Optics Express
Yoshiki Seto, Kouki Kato, Ryota Tsukada, Hiroki Suzuki, Yuuki Kaneko, Yoshiki Kojo, Hideyuki Sato, Satomi Onoue
The present study aimed to verify the efficacy of tranilast (TL) for treating inflammatory bowel disease (IBD) with the use of an experimental colitis model. The experimental colitis model was prepared by intrarectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS; 40mg/kg) dissolved in water containing 25% ethanol. The pharmacological effects of TL after repeated oral administration were evaluated by biomarker and histological analyses, and the pharmacokinetic behavior of TL was also examined after single oral administration...
April 20, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Annette M Bachand, Sandra I Sulsky, Geoffrey M Curtin
Researchers and those responsible for evaluating and implementing policies intended to reduce population harm must assess the potential for both intended and unintended consequences associated with those policies. Such assessments should be based on the combined dimensions of magnitude, and thus likelihood, of shifts in exposure patterns needed to produce a population benefit or harm, and magnitude of the expected population benefit or harm. In response to this assessment need, we provide a conceptual description of the dynamic population modeler, DPM(+1), as well as illustrative analyses that estimate the effects on all-cause mortality, life expectancy, and quality of life-adjusted life expectancy if exposure patterns in the population shift from a higher risk product (e...
April 24, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
Yacov Y Haimes
The emergence of the complexity characterizing our systems of systems (SoS) requires a reevaluation of the way we model, assess, manage, communicate, and analyze the risk thereto. Current models for risk analysis of emergent complex SoS are insufficient because too often they rely on the same risk functions and models used for single systems. These models commonly fail to incorporate the complexity derived from the networks of interdependencies and interconnectedness (I-I) characterizing SoS. There is a need to reevaluate currently practiced risk analysis to respond to this reality by examining, and thus comprehending, what makes emergent SoS complex...
April 24, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
Bing Wu, Xinping Yan, Yang Wang, Di Zhang, C Guedes Soares
A ship that is not under control (NUC) is a typical incident that poses serious problems when in confined waters close to shore. The emergency response to NUC ships is to select the best risk control options, which is a challenge in restricted conditions (e.g., time limitation, resource constraint, and information asymmetry), particularly in inland waterway transportation. To enable a quick and effective response, this article develops a three-stage decision-making framework for NUC ship handling. The core of this method is (1) to propose feasible options for each involved entity (e...
April 24, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
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