Browsing by Author "Liu, Y. L."

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115 Gbit/s downstream and 10 Gbit/s upstream TWDM-PON together with 11.25 Gbit/s wireless signal utilizing OFDM-QAM modulation
(2014-03-01)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Liu, Y. L.
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光電工程學系
In this work, we propose and investigate a 115 Gbit/s (4 x 28.75 Gbit/s) downstream and 10 Gbit/s upstream time- and wavelength-division-multiplexing passive optical network (TWDM-PON) together with 11.25 Gbit/s wireless broadcasting signal using multi-band orthogonal-frequency-divisionmultiplexing (OFDM) modulation within 10 GHz bandwidth. Here, to compensate the power fading and chromatic dispersion in the higher frequency, we utilize a -0.7 chirp parameter Mach-Zehnder modulator (MZM) for the OFDM signal. Hence, negative power penalties of -0.3 and -0.4 dB in the downstream and broadcasting wireless signals; and power penalty of 0.3 dB in the upstream signal are measured at the bit error rate (BER) of 3.8 x 10 (3) after 20 km standard single mode fiber transmission without dispersion compensation. (C) 2013 Elsevier Inc. All rights reserved.
2.5-10 Gbit/s laser source based on two optical-injection Fabry-Perot laser diodes
(2013-12-01)
Wu, Y. F.
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Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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Sung, J. Y.
In this investigation, a wavelength tunable laser source based on optical-injection of two Fabry-Perot laser diodes (FP-LDs) is demonstrated. In the proposed laser source, a self-injection locked master FP-LD provides a stable continuous-wave (CW) lasing, which wavelength can be selected by means of an optical tunable bandpass filter (TBF). The CW wavelength is launched into another FP-LD (the slave laser) for direct signal modulation. In this two optical-injection FP-LD architecture, directly modulation of 2.5 Gbit/s on-off keying (OOK) and 10 Gbit/s orthogonal frequency division multiplexing (OFDM) signals can be achieved in the proposed laser source with negligible power penalty after 25 km single-mode-fiber (SMF) transmission. (C) 2013 Elsevier Inc. All rights reserved.
A PRACTICAL IN-HOME ILLUMINATION CONSIDERATION TO REDUCE DATA RATE FLUCTUATION IN VISIBLE LIGHT COMMUNICATION
(2015-04-01)
Chow, C. W.
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Liu, Y.
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Yeh, C. H.
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Sung, J. Y.
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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.
AC-based phosphor LED visible light communication by utilizing novel signal modulation
(2013-10-01)
Liu, Y. F.
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Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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光電工程學系
We propose and demonstrate a new AC-light emitting diode based visible light communication system, in which the message signal is up-converted to 400 kHz frequency band and combine with the 60 Hz AC-power from the outlet. A special design bias-tee circuit is first implemented to combine the message signal and the AC-power for minimizing the signal distortion. Thus, the spectra of both signals are well separated. A special design clock recovery is used to synchronize the AC-power with the message signal; hence the message signal can be correctly applied to the rectified AC-power cycle.
Adaptive 84.44-190 Mbit/s phosphor-LED wireless communication utilizing no blue filter at practical transmission distance
(2014-04-21)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Chen, J.
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Liu, Y. L.
We propose and experimentally demonstrate a white-light phosphor-LED visible light communication (VLC) system with an adaptive 84.44 to 190 Mbit/s 16 quadrature-amplitude-modulation (QAM) orthogonal-frequency-division-multiplexing (OFDM) signal utilizing bit-loading method. Here, the optimal analogy pre-equalization design is performed at LED transmitter (Tx) side and no blue filter is used at the Rx side. Hence, the similar to 1 MHz modulation bandwidth of phosphor-LED could be extended to 30 MHz. In addition, the measured bit error rates (BERs) of < 3.8 x 10(-3) [forward error correction (FEC) threshold] at different measured data rates can be achieved at practical transmission distances of 0.75 to 2 m. (C) 2013 Optical Society of America
Adaptive upstream optical power adjustment depending on required power budget in PON access
(2012-11-01)
Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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光電工程學系
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Department of Photonics
According to the present passive optical network (PON) standard, the fiber transmission lengths are from 500 m to 20 km between the optical line terminal (OLT) and different optical network units (ONUs). It will result in difference power losses (Delta P-loss) from 4 to 5 dB. Hence, we propose to adjust adaptively the output optical power of the upstream laser diode (LD) depending on the different fiber lengths. With the different fiber transmission lengths, we can properly adjust the bias current and modulation index of upstream LD for energy-saving. We characterize and analyze experimentally the relationship of output optical power and modulation amplitude Vamp under different fiber transmissions in PON access. Moreover, due to the adaptive power control of upstream signal, the optical upstream equalization also can be retrieved with power variation of 1.1 dB in this experiment. (C) 2012 Elsevier B.V. All rights reserved.
Demonstration of 76 Mbit/s Real-Time Phosphor-LED Visible Light Wireless System
(2014)
Yeh, C. H.
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Liu, Y. L.
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Chow, C. W.
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光電工程學系
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Department of Photonics
We demonstrate a 74 Mbit/s real-time phosphor-LEDbased visible light communication (VLC) system with compact size by using polarization-based 2x2 MIMO technology. The relationships of received power and signal petformance are analyzed.
Demonstration of bi-directional LED visible light communication using TDD traffic with mitigation of reflection interference
(2012-10-08)
Liu, Y. F.
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Yeh, C. H.
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Chow, C. W.
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Liu, Y.
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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
Demonstration of using injection-locked Fabry-Perot laser diode for 10 Gbit/s 16-QAM OFDM WDM-PON
(1970-01-01)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Sung, J. Y.
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Liu, Y. L.
"A 10 Gbit/s OFDM upstream transmission has been investigated by using a Fabry-Perot laser diode (FP-LD) based ONU with seeding-light in a colourless WDM-PON. Also demonstrated is the relationship of CW injection power and SNR of each OFDM subcarrier for a modelocked FP-LD. Moreover, when a 16-QAM OFDM modulation is applied in a modelocked FP-LD, -15.7 dBm received sensitivity at the BER of 3.8 x 10(-3) can be obtained after 20 km fibre transmission."
Dynamic Bandwidth Allocation for Multi-Band OFDM Wireless VLC System
(2016-01-01)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Liu, Y. L.
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光電工程學系
We propose a multi-band OFDM modulation for wireless VLC system together with dynamic bandwidth allocation. In addition, the proposed modulation format also can enhance the maximum VLC traffic rate to 17.8% without using blue filter.
High-Speed Phosphor-LED Wireless Communication System Utilizing No Blue Filter
(2014-01-01)
Yeh, C. H.
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Chow, C. W.
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Chen, H. Y.
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Chen, J.
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Liu, Y. L.
In this paper, we propose and investigate an adaptively 84.44 to 190 Mb/s phosphor-LED visible light communication (VLC) system at a practical transmission distance. Here, we utilize the orthogonal-frequency-division-multiplexing quadrature-amplitude-modulation (OFDM-QAM) modulation with power/bit-loading algorithm in proposed VLC system. In the experiment, the optimal analogy pre-equalization design is also performed at LED-Tx side and no blue filter is used at the Rx side for extending the modulation bandwidth from 1 MHz to 30 MHz. In addition, the corresponding free space transmission lengths are between 75 cm and 2 m under various data rates of proposed VLC. And the measured bit error rates (BERs) of < 3.8x10(-3) [forward error correction (FEC) limit] at different transmission lengths and measured data rates can be also obtained. Finally, we believe that our proposed scheme could be another alternative VLC implementation in practical distance, supporting > 100 Mb/s, using commercially available LED and PD (without optical blue filtering) and compact size.
Investigation of no analogue-equalization and blue filter for 185 Mbps phosphor-LED wireless communication
(2015-07-01)
Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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Chen, H. Y.
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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.
Mitigation of LED Nonlinearity Using Adaptive Equalization for Visible Light Communications
(2017-01-01)
Hsu, C. W.
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Hsu, Y.
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Chen, G. H.
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Wei, L. Y.
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Chow, C. W.
We demonstrate using bit-loading orthogonal-frequency-division-multiplexing (OFDM) and adaptive Volterra equalization to mitigate the light-emitting-diode (LED) nonlinearity; hence the data rate of LED based visible-light-communication (VLC) can be increased to > 700 Mbit/s.
Performance and Limitation of Radio-over-Fiber Network Using Standard WiMAX Signal
(2009)
Yeh, C. H.
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Chow, C. W.
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Shih, F. Y.
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Wang, C. H.
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Wu, Y. F.
WiMAX is considered for the last mile wireless connectivity to provide flexible broadband services to end users. And Radio over Fiber (RoF) system has attracted industry and research interest to extend the wireless cell coverage and reduce the cost by using the distributed remote antenna units (RAUs). Here, the performance of WiMAX RoF system will be characterized. Results show that the effective RoF transmission fiber length can be limited due to the time division duplex (TDD) framing in the connection using standard WiMAX signal generated by a commercial WiMAX bias station. WiMAX RoF performances of throughput and packet-loss at different link lengths are investigated and analyzed. Besides, a robust TDD switch architecture used in each RAU will be proposed for the WiMAX RoF system.
Plasmon-enhanced photoluminescence from bioconjugated gold nanoparticle and nanodiamond assembly
(2011-04-11)
Liu, Y. L.
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Sun, K. W.
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應用化學系
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Department of Applied Chemistry
In this letter, we coupled nanodiamonds (NDs) with gold nanoparticles of different sizes using two complementary DNA sequences. After hybridizing the gold nanoparticles on the NDs, we observed the enhancement of the photoluminescence (PL) signals originating from the nitrogen-vacancy (N-V) center of the ND. The enhancement was attributed to the plasmon field created by the gold nanoparticles. The line shape of the enhanced PL spectra was also affected by the sizes of the attached nanoparticles due to their different resonant plasma frequencies. The signal enhancement can be used as an indexing tool for biosensing applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3576852]
Polarization-multiplexed 2 X 2 phosphor-LED wireless light communication without using analog equalization and optical blue filter
(2015-01-01)
Yeh, C. H.
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Chen, H. Y.
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Liu, Y. L.
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Chow, C. W.
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光電工程學系
We propose and experimentally demonstrate a 380 (2 x 190) Mbps phosphor-light-emitting-diode (LED) based visible light communication (VLC) system by using 2 x 2 polarization-multiplexing design for in-building access applications. To the best of our knowledge, this is the first time of employing polarization-multiplexing to achieve a high VLC transmission capacity by using phosphor-based white-LED without optical blue filter. Besides, utilizing the optimum resistor-inductor-capacity (RLC) bias-tee design, it can not only perform the function of combining the direct-current (DC) and the electrical data signal, but also act as a simple LED-Tx circuit. No optical blue filter and complicated post-equalization are required at the Rx. Here, the orthogonal-frequency-division-multiplexing (OFDM) quadrature-amplitude-modulation (QAM) with bit-loading is employed to enhance the transmission data rate. (C) 2014 Elsevier B.V. All rights reserved.
Protein Functionalized Nanodiamond Arrays
(2010-06-01)
Liu, Y. L.
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Sun, K. W.
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應用化學系
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Department of Applied Chemistry
Various nanoscale elements are currently being explored for bio-applications, such as in bio-images, bio-detection, and bio-sensors. Among them, nanodiamonds possess remarkable features such as low bio-cytotoxicity, good optical property in fluorescent and Raman spectra, and good photostability for bio-applications. In this work, we devise techniques to position functionalized nanodiamonds on self-assembled monolayer (SAMs) arrays adsorbed on silicon and ITO substrates surface using electron beam lithography techniques. The nanodiamond arrays were functionalized with lysozyme to target a certain biomolecule or protein specifically. The optical properties of the nanodiamond-protein complex arrays were characterized by a high throughput confocal microscope. The synthesized nanodiamond-lysozyme complex arrays were found to still retain their functionality in interacting with E. coli.
Ring-Based WDM Access Network Providing Both Rayleigh Backscattering Noise Mitigation and Fiber-Fault Protection
(2012-10-15)
Yeh, C. H.
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Chow, C. W.
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Huang, S. P.
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Sung, J. Y.
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Liu, Y. L.
In this paper, we propose and investigate a ring-based wavelength-division-multiplexing passive optical network (WDM-PON) providing both Rayleigh backscattering (RB) noise mitigation and fiber-fault protection. The proposed ring-based WDM-PON has a dual-ring architecture to protect and restore any fiber fault. Besides, the ring architecture also can mitigate the RB beat noise, since the RB and the upstream wavelengths are propagating in opposite directions. Here, we discuss and analyze the characteristics of the downstream signals using 10 Gb/s ON-OFF keying (OOK), 10 Gb/s differential phase-shift keying, and 10 Gb/s orthogonal frequency-division multiplexing (OFDM) modulations, respectively. Moreover, we also investigate the upstream traffic using the 2.5 Gb/s OOK and 10 Gb/s OFDM generated by the directly modulated reflective semiconductor optical amplifier-based optical network unit, respectively.
Self-protected ring-star-architecture TDM passive optical network with triple-play management
(2011-06-15)
Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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光電工程學系
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Department of Photonics
A new self-protected apparatus in ring-star-architecture for time division multiplexed passive optical network (TDM-PON) against fiber-fault; together with triple-play management in optical layer is proposed and investigated. Different scenarios of fiber-fault locations are also discussed and analyzed. Besides, the performance of data traffics in both uplink and downlink directions are also measured and studied. Standard CAN video signal distribution to each ONUs is also performed, showing the proposed access network cannot only have self-restored function, but also can manage triple-play services in the optical layer. (C) 2011 Elsevier B.V. All rights reserved.
Self-Restored Ring-Star-Architecture TDM-PON
(2009-01-01)
Yeh, C. H.
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Chow, C. W.
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Liu, Y. L.
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光電工程學系
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Department of Photonics
We propose a new self-restored ring star architecture for TDM-PON against fiber fault, together with triple-play management in optical layer Besides, the performance of data traffics in both uplink and downlink are also studied