Browsing by Author "Liu, Y."

Now showing 1 - 20 of 20

13 Gbit/s WDM-OFDM PON using RSOA-based colourless ONU with seeding light source in local exchange
(2011-10-27)
Chow, C. W.
;
Yeh, C. H.
;
Wu, Y. F.
;
Chen, H. Y.
;
Lin, Y. H.
Optical-carrier-distribution using reflective-semiconductor-optical-amplifier (RSOA)-based colorless optical-networking-unit (ONU) is a promising candidate for the wavelength-division-multiplexed passive-optical-network (WDM-PON). However, commercial available RSOA has a typical modulation-bandwidth of similar to 1 GHz, which is not enough for the future bandwidth demand. Here we demonstrate a WDM-PON using 1 GHz bandwidth RSOA-based ONU, which can be operated up to 13 Gbit/s. Experimental results show that 20 km singlemode-fibre transmission of the 13 Gbit/s orthogonal-frequency-division-multiplexed (OFDM) signal can be achieved with bit-error rate lower than the forward error correction threshold.
A high precision calibration of the nonlinear energy response at Daya Bay
(2019-10-01)
Adey, D.
;
An, F. P.
;
Balantekin, A. B.
;
Band, H. R.
;
Bishai, M.
A high precision calibration of the nonlinearity in the energy response of the Daya Bay Reactor Neutrino Experiment's antineutrino detectors is presented in detail. The energy nonlinearity originates from the particle-dependent light yield of the scintillator and charge-dependent electronics response. The nonlinearity model is constrained by.. calibration points from deployed and naturally occurring radioactive sources, the.. spectrum from B-12 decays, and a direct measurement of the electronics nonlinearity with a new flash analog-to-digital converter readout system. Less than 0.5% uncertainty in the energy nonlinearity calibration is achieved for positrons of kinetic energies greater than 1 MeV.
A PRACTICAL IN-HOME ILLUMINATION CONSIDERATION TO REDUCE DATA RATE FLUCTUATION IN VISIBLE LIGHT COMMUNICATION
(2015-04-01)
Chow, C. W.
;
Liu, Y.
;
Yeh, C. H.
;
Sung, J. Y.
;
Liu, Y. L.
Visible light communication based on LED has attracted more and more attention. As the primary function of LED luminaries is optimized for lighting and illumination, it challenges the communication properties of VLC. An investigation based on different in-home illumination conditions using commercially available white-light LED luminaries to optimize both illumination and communication is highly desirable. In this work, we investigate joint illumination and communication systems to provide an in-home lighting and VLC system. We first focus on the performance constraints set by illumination properties and discuss lighting conditions using different kinds of commercially available luminaries, beam angles, and LED lamp arrangements, and consider reflections off different wall materials. Then we propose and experimentally demonstrate a white-light phosphor-based LED adaptive data rate VLC system. Finally, the achievable data rates of a joint illumination and VLC system are discussed based on the experimental results, and an environment with reduced VLC data rate fluctuation can be achieved.
Adaptive Control of OFDM Data Rate for LED Visible Light Communications in Different Free Space Transmission Distances and Offsets
(2012)
Liu, Y. F.
;
Yeh, C. H.
;
Chow, C. W.
;
Liu, Y.
;
光電工程學系
Using orthogonal-frequency-division-multiplexing (OFDM) for light-emitting-diode (LED) visible-light-communication (VLC) is a promising approach. Here we demonstrate an LED communication link with adaptive control of the OFDM data rate for different communication environments.
Adaptive scheme for maintaining the performance of the in-home white-LED visible light wireless communications using OFDM
(2013-04-01)
Chow, C. W.
;
Yeh, C. H.
;
Liu, Y. F.
;
Huang, P. Y.
;
Liu, Y.
Spectral-efficient orthogonal frequency division multiplexing (OFDM) is a promising modulation format for the light-emitting-diode (LED) optical wireless (OW) visible light communication (VLC). VLC is a directional and line-of-sight communication; hence the offset of the optical receiver (Rx) and the LED light source will result in a large drop of received optical power. In order to keep the same luminance of. the LED light source, we propose and demonstrate an adaptive control of the OFDM modulation-order to maintain the VLC transmission performance. Experimental results confirm the feasibility of the proposed scheme. (C) 2012 Elsevier B.V. All rights reserved.
ANALYSIS OF TUNABLE FLAT DISPERSION OF GERMANIUM DOPED FIBER WITH LIQUID CLADDING
(2010-06-01)
Liu, Y.
;
Chen, N.
;
Lai, Y.
;
Chi, S.
;
光電工程學系
We demonstrate numerically the tunable dispersion-flattened fibers can be achieved by immersing the Ge-doped fiber core in different liquid claddings. The dispersion slope can be flattened over 1100-1700 nm, which is suitable for tunable supercontinuum,generation with pumping wavelength in fiber communication or other wavelength regions. Finally. we demonstrate the feasibility, to fabricate the proposed structure with chemical etching method. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1357-1359, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25209
Demonstration of bi-directional LED visible light communication using TDD traffic with mitigation of reflection interference
(2012-10-08)
Liu, Y. F.
;
Yeh, C. H.
;
Chow, C. W.
;
Liu, Y.
;
Liu, Y. L.
In this work, we experimentally demonstrate a bi-directional transmission link using light emitting diode (LED) visible light communication (VLC) for both downlink and uplink paths. Time-division-duplex (TDD) is proposed and demonstrated to significantly eliminate the reflection interference in VLC. A free space bi-directional transmission of 2 m using simple on-off keying (OOK) modulation with bit error rate (BER) of < 10(-5) in both directions are achieved. Moreover, the influence of reflection interference is analyzed, showing the proposed scheme can significantly eliminate the reflection interference. (C) 2012 Optical Society of America
ELECTROPHYSIOLOGICAL MODELING OF THE RIGHT ATRIUM WITH THORACIC SLICES AND ITS NUMERICAL SOLUTION ON GPU
(2017-11-01)
Zhang, H.
;
Liu, Y.
;
Huang, X.
;
Lin, S. F.
;
分子醫學與生物工程研究所
Extraction of the U-235 and Pu-239 Antineutrino Spectra at Daya Bay
(2019-09-13)
Adey, D.
;
An, F. P.
;
Balantekin, A. B.
;
Band, H. R.
;
Bishai, M.
This Letter reports the first extraction of individual antineutrino spectra from U-235 and Pu-239 fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5 x 10(6) inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, U-235 and Pu-239, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the U-235 (Pu-239) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0 sigma for U-235 spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3 sigma. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3 sigma is observed.
Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments
(2020-08-10)
Adamson, P.
;
An, F. P.
;
Anghel, I.
;
Aurisano, A.
;
Balantekin, A. B.
Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the theta(mu e) mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Delta m(41)(2), excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CLs for Delta m(41)(2) < 13 eV(2). Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CLs for Delta m(41)(2) < 1.6 eV(2).
Improved measurement of the reactor antineutrino flux at Daya Bay
(2019-09-09)
Adey, D.
;
An, F. P.
;
Balantekin, A. B.
;
Band, H. R.
;
Bishai, M.
This work reports a precise measurement of the reactor antineutrino flux using 2.2 million inverse beta decay (IBD) events collected with the Daya Bay near detectors in 1230 days. The dominant uncertainty on the neutron detection efficiency is reduced by 56% with respect to the previous measurement through a comprehensive neutron calibration and detailed data and simulation analysis. The new average IBD yield is determined to be (5.91 +/- 0.09) x 10(-43) cm(2)/fission with total uncertainty improved by 29%. The corresponding mean fission fractions from the four main fission isotopes U-235, U-238, Pu-239, and( 241)Pu are 0.564, 0.076, 0.304, and 0.056, respectively. The ratio of measured to predicted antineutrino yield is found to be 0.952 +/- 0.014 +/- 0.023 (1.001 +/- 0.015 +/- 0.027) for the Huber-Mueller (ILL-Vogel) model, where the first and second uncertainty are experimental and theoretical model uncertainty, respectively. This measurement confirms the discrepancy between the world average of reactor antineutrino flux and the Huber-Mueller model.
Improved modulation speed of LED visible light communication system integrated to main electricity network
(2011-07-21)
Chow, C. W.
;
Yeh, C. H.
;
Liu, Y. F.
;
Liu, Y.
;
光電工程學系
In addition to the illumination purpose, using a light-emitting diode (LED) for indoor optical wireless communication has attracted much attention recently. Proposed and demonstrated is the use of a simple on-off keying (OOK) predistortion scheme together with a simple first-order resistance-capacitance equalisation circuit to increase the modulation speed of a white-light high-brightness LED (HB-LED). Optical filtering and complicated modulation formats are not required. Since only OOK modulation is used, the signal modulation and detection are very simple. Also are compared the different combinations of the system designs. By using first-order equalisation together with a predistortion, a bit-error rate of <10(-10) at 10 Mbit/s can be easily achieved when using the 1 MHz bandwidth phosphor-based white HB-LED.
Investigation of 4-ASK modulation with digital filtering to increase 20 times of direct modulation speed of white-light LED visible light communication system
(2012-07-16)
Yeh, C. H.
;
Liu, Y. F.
;
Chow, C. W.
;
Liu, Y.
;
Huang, P. Y.
In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) modulation with digital filtering to enhance the direct modulation speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct modulation speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct modulation speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct modulation speed of white-light LED VLC system is demonstrated by using digital filter only and without using optical blue filter. (C) 2012 Optical Society of America
Investigation of no analogue-equalization and blue filter for 185 Mbps phosphor-LED wireless communication
(2015-07-01)
Yeh, C. H.
;
Chow, C. W.
;
Liu, Y. L.
;
Chen, H. Y.
;
Liu, Y.
In this demonstration, we first propose an optimal analogue front end circuit without employing pre-equalization (series peaking) to increase the modulation bandwidth of phosphor-LED in visible light communication (VLC) transmission. And there is no blue filter and post-equalization in the client side. Here, only using optimal adjustment of resistance (R), inductance (L), and capacitance (C) in bias-tee to compensate the impedance matching of phosphor-LED, nearly 32 MHz modulation bandwidth can be accomplished. Therefore, utilizing orthogonal frequency division multiplexed modulation with bit-loading algorithm in VLC system, 185 Mbps data rate can be achieved under a transmission distance of 80 cm.
Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay
(2018-12-14)
Adey, D.
;
An, F. P.
;
Balantekin, A. B.
;
Band, H. R.
;
Bishai, M.
We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor (nu) over bar (e) inverse beta decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic Li-9 and He-8 background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative (nu) over bar (e) rates and energy spectra among detectors yields sin(2)2 theta(13) = 0.0856 +/- 0.0029 and Delta m(32)(2) = (2.471(-0.070)(+0.068)) x 10(-3) eV(2) assuming the normal hierarchy, and Delta m(32)(2) = -(2.575(-0.070)(+0.068)) x 10(-3) eV(2) assuming the inverted hierarchy.
Plasmonic Coupler for Silicon-Based Micro-Slabs to Plasominc Nano-Gap Waveguide Mode Coversion Enhancement
(2013-06-01)
Liu, Y.
;
Lai, Y.
;
Chang, K.
;
光電工程學系
;
Department of Photonics
We investigate a short (similar to 1.5 mu m) "partially" corrugated tapered waveguide for silicon-based micro-slab waveguide to plasmonic nano-gap waveguide mode conversion at the optical communication frequency. The structure is designed to achieve more precise mode matching between the silicon slabs and plasmonic waveguides. High transmission efficiencies up to 87% similar to 98% have been demonstrated numerically. The results show that the corrugated structure should not only be helpful for realizing full on-chip silicon plasmonic devices but also a good choice for mode coupling enhancement from dielectric waveguides to plasmonic waveguides. Meanwhile, we point out that the coupling mechanism reported here is different from that achieved by exciting surface plasmon polaritions (SPPs) at metal surfaces reported in the literature [18], [19].
Search for a time-varying electron antineutrino signal at Daya Bay
(2018-11-20)
Adey, D.
;
An, F. P.
;
Balantekin, A. B.
;
Band, H. R.
;
Bishai, M.
A search for a time-varying (nu) over bar (e) signal was performed with 621 days of data acquired by the Daya Bay Reactor Neutrino Experiment over 704 calendar days. The time spectrum of the measured (nu) over bar (e) flux normalized to its prediction was analyzed with a Lomb-Scargle periodogram, which yielded no significant signal for periods ranging from 2 hours to nearly 2 years. The normalized time spectrum was also fit for a sidereal modulation under the Standard Model Extension (SME) framework to search for Lorentz and CPT violation (LV-CPTV). Limits were obtained for all six flavor pairs (e) over bar(mu) over bar, (e) over bar(tau) over bar, (mu) over bar(tau) over bar, (e) over bar(e) over bar, (mu) over bar(mu) over bar and (tau) over bar(tau) over bar by fitting them one at a time, constituting the first experimental constraints on the latter three. Daya Bay's high statistics and unique layout of multiple directions from three pairs of reactors to three experimental halls allowed the simultaneous constraint of individual SME LV-CPTV coefficients without assuming others contribute negligibly, a first for a neutrino experiment.
Signal Generation and Transmission of 13-Gb/s OFDM Signal using RSOA in Carrier Distribution WDM-PON
(2012)
Chow, C. W.
;
Yeh, C. H.
;
Lin, Y. H.
;
Liu, Y.
;
光電工程學系
We demonstrate the 20-km transmission of 13-Gb/s orthogonal-frequency-division-multiplexed (OFDM) signal generated by using a 1.2-Ghz bandwidth reflective-semiconductor-optical-amplifier (RSOA) based optical-networking-unit (ONU). The bit-error-rate (BER) performance is within the forward-error-correction (FEC) threshold.
Signal Remodulation PON without Power Sacrifice using PolSK
(2008)
Chow, C. W.
;
Liu, Y.
;
Yeh, C. H.
;
Chi, S.
;
光電工程學系
We propose and demonstrate a novel signal remodulation scheme using PolSK with high extinction-ratio. Error-free was achieved in a 20km reach 10Gb/s DWDM-PON without dispersion compensation.
Signal remodulation with high extinction ratio 10-gb/s DPSK signal for DWDM-PONS
(2008)
Chow, C. W.
;
Liu, Y.
;
Kwok, C. H.
;
光電工程學系
;
Department of Photonics
We propose and demonstrate a novel wavelength remodulation scheme using DPSK in both downstream/upstream signals with high extinction-ratio. Error-free operation was achieved in a 20-km-reach 10-Gb/s DWDM-PON without dispersion compensation. (c) 2008 Optical Society of America.