Browsing by Author "Wu, Yu-Fu"

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A simple self-restored fiber Bragg grating (FBG)-based passive sensing ring network
(2009-04-01)
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Wang, Chia-Husan
;
Shih, Fu-Yuan
;
Wu, Yu-Fu
In this investigation, we propose and experimentally investigate a simple self-restored fiber Bragg grating (FBG)-based sensor ring system. This proposed multi-ring passive sensing architecture does not require active components in the network. In this experiment, the network survivability and capacity for the multi-point sensor systems are also enhanced. Besides, the tunable laser source (TLS) is adopted in a central office (CO) for FBG sensing. The survivability of an eight-point FBG sensor is examined and analyzed. It is cost effective since the sensing system is entirely centralized in the CO. Experimental results show that the proposed system can enhance the reliability of the FBG sensing network for large-scale and multi-point architecture.
Demonstration of a self-injected Fabry-Perot laser for dual-wavelength tuning together with different mode-spacing
(2014-06-01)
Yeh, Chien-Hung
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Chow, Chi-Wai
;
Wu, Yu-Fu
;
Lu, Shao-Sheng
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光電工程學系
In this demonstration, we experimentally investigate a dual-ring fiber laser architecture to achieve dual-wavelength-tunable by utilizing the self-injected Fabry-Perot laser diode (FP-LD) mechanism. Here, two tunable bandpass filters (TBFs) are utilized in the proposed laser structure to obtain the dual-wavelength with single-longitudinal-mode (SLM). The different mode-spacing of the proposed dual-wavelength fiber laser can also be tuned between 20.8 and 1.3 nm, due to the effective gain amplification of FP-LD. Moreover, we can employ the different FP-LDs with various gain distributions to achieve wide wavelength range tuning.
Design of Visible Light Communication System for Maintaining Uniform Data Rate
(2014-01-01)
Sung, Jiun-Yu
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Lin, Wan-Feng
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Wu, Yu-Fu
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Chow, Chi-Wai
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Yeh, Chien-Hung
Light-emitting diode (LED) is gradually replacing the fluorescent lamp for lighting. Higher modulation bandwidth of LEDs makes the additional application of visible light communication (VLC) possible. Every location of a VLC system should be provided by equal data rate for smooth communication. However, locations away from the LED lamp have less power. These low-power locations have lower signal-to-noise ratio (SNR); and hence lower data rate can be achieved. For achieving high capacity VLC, strategies should be adequately provided to mitigate this problem. Moreover, for some real-time continuous applications, such as video and voice, latency reduction plan should also be considered. In this paper, an orthogonal frequency-division multiplexing access (OFDMA) based system was proposed to solve the above problem. Because we do not use time-division multiplexing access (TDMA) based system, the latency issue can be reduced. The OFDMA based system is also beneficial for large scale operation because the user bandwidth is not reduced by TDM mechanism. Signal-to-noise-plus-interference ratio (SNIR) distribution of the VLC system is designed to ensure uniform and optimal system capacity. Discrete multi-tone (DMT) is used for this VLC system. The DMT subcarriers are bit-loaded depending on the LED frequency response. More subcarriers are allocated for communication at low SNIR locations. Hence, nearly equal data rate can be provided everywhere. Demonstration of 17 Mb/s/LED data rate was provided.
Experimental demonstration of CW light injection effect in upstream traffic TDM-PON
(2010-06-01)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Wu, Yu-Fu
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Shih, Fu-Yuan
;
Chi, Sien
High capacity time-division-multiplexed passive optical network (TDM-PON) is an emerging fiber access network that deploys optical access lines between a carrier's central office (CO) and a customer sites. In this investigation, we demonstrate and analyze the continuous wave (CW) upstream effect in TDM-PONs. Besides, we also propose and design a protection apparatus in each optical network unit (ONU) to avoid a CW upstream traffic in TDM-PONs due to sudden external environment change or ONU failure. When an upstream CW injection occurs in TDM access network, the protection scheme can stop the CW effect within a few ms to maintain the entire data traffic. (C) 2010 Elsevier Inc. All rights reserved.
Performance of Long-Reach Passive Access Networks Using Injection-Locked Fabry-Perot Laser Diodes With Finite Front-Facet Reflectivities
(2013-06-15)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Wu, Yu-Fu
;
Huang, Sung-Ping
;
Liu, Yen-Liang
In this study, we use the injection-locked Fabry-Perot laser diodes (FP-LDs) with front-facet reflectivities of 10% and 35% respectively, as colorless optical networking unit (ONU) in long-reach passive optical networks (LR-PONs). Here, the injection-locked FP-LD is directly modulated at 2.5 Gbit/s on-off keying (OOK) and 10 Gbit/s orthogonal-frequency-division-multiplexing (OFDM) modulations for upstream traffic transmission over 60 km of single-mode fiber (SMF). Different operating parameters for the injection-locked FP-LD to achieve higher data rate transmission are reported.
Stable and Wavelength-Tunable Self-Injected Reflective Semiconductor Optical Amplifier-Based Fiber Laser
(2015-08-01)
Wu, Yu-Fu
;
Yeh, Chien-Hung
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Chow, Chi-Wai
;
Sung, Jiun-Yu
;
Chen, Jing-Heng
In this investigation, we propose and demonstrate a stable and wavelength-tunable self-injected reflective semiconductor optical amplifier (RSOA)-based laser by using the Faraday rotator mirror (FRM) and the fiber mirror (FM) serving as a reflected element, respectively. Here, a 1.2-GHz RSOA can be enhanced to similar to 3 GHz by utilizing a self-injected mechanism. In the measurement, applying the optical orthogonal frequency-division multiplexing quadrature amplitude modulation (OFDM-QAM) with a bit-loading algorithm on the self-injected RSOA directly, the proposed laser can achieve a 3.5-Gb/s data rate in a 20-km single-mode-fiber transmission below a forward error correction (FEC) threshold. Moreover, the related output performance of the proposed RSOA-based laser is also discussed, whereas the FRM and the FM are utilized for comparisons.
Tunable Dual-Wavelength Fiber Laser Using Optical-Injection Fabry-Perot Laser
(2008-11-01)
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Shih, Fu-Yuan
;
Wang, Chia-Hsuan
;
Wu, Yu-Fu
In this investigation, we propose and experimentally demonstrate a dual-wavelength fiber laser based on a self-injected Fabry-Perot laser diode and an erbium-doped fiber. The dual-wavelength tuning range is 39.49 nm, from 1526.27 to 1565.76 nm. And the mode spacing of the dual-wavelength can be tuned from 1.32 to 39.49 nm. In addition, the output power difference of the dual-wavelength can be controlled and smaller than 1 dB.
Tunable Dual-Wavelength Fiber Laser Using Optical-Injection Fabry-Perot Laser
(2009-01-01)
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Shih, Fu-Yuan
;
Wang, Chia-Hsuan
;
Wu, Yu-Fu
In this investigation, we propose and experimentally demonstrate a dual-wavelength fiber laser based on a self-injected Fabry-Perot laser diode and an erbium-doped fiber. The dual-wavelength tuning range is 39.49 run, from 1526.27 to 1565.76 nm, and the mode spacing of the dual-wavelength can be tuned from 1.32 to 39.49 run. In addition, the output power difference of the dual-wavelength can be controlled and smaller than 1 dB.
Using a 1.2 GHz bandwidth reflective semiconductor optical amplifier with seeding light by 64-quadrature amplitude modulation orthogonal frequency division multiplexing modulation to achieve a 10-gbits/s upstream rate in long-reach passive optical network access
(2012-01-01)
Yeh, Chien-Hung
;
Chen, Hsing-Yu
;
Chow, Chi-Wai
;
Wu, Yu-Fu
;
光電工程學系
We use a commercially available 1.2 GHz bandwidth reflective semiconductor optical amplifier (RSOA)-based optical network unit (ONU) to achieve 10-gbits/s upstream traffic for an optical orthogonal frequency division multiplexing (OFDM) long-reach passive optical network (LR-PON). This is the first time the 64-quadrature amplitude modulation (QAM) OFDM format has been applied to RSOA-ONU to achieve a 75 km fiber transmission length. In the proposed LR-PON, the upstream power penalty of 5.2 dB at the bit error rate of 3.8 x 10(-3) is measured by using a 64-QAM OFDM modulation after the 75 km fiber transmission without dispersion compensation. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.OE.51.1.015004]
Using four wavelength-multiplexed self-seeding Fabry-Perot lasers for 10 Gbps upstream traffic in TDM-PON
(2008-11-10)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Wang, Chia-Husan
;
Shih, Fu-Yuan
;
Wu, Yu-Fu
In this paper, we propose and experimentally investigate a simple self-injection Fabry-Perot laser scheme on each optical network unit (ONU) for 10 Gbps TDM passive optical networks (PONs). Based on the proposed four wavelength-multiplexed 2.5 Gbps lasers, the 10 Gbps uplink traffic can be achieved at a cost-effective way. The network architecture and performance have also been analyzed and discussed. (C) 2008 Optical Society of America
Using OOK Modulation for Symmetric 40-Gb/s Long-Reach Time-Sharing Passive Optical Networks
(2010-05-01)
Yeh, Chien-Hung
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Chow, Chi-Wai
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Wang, Chia-Hsuan
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Wu, Yu-Fu
;
Shih, Fu-Yuan
Due to the requirement of broad bandwidth for next-generation access networks, present passive optical networks (PONs) will be upgraded to 40 Gb/s or higher data rate PONs. Hence, we propose and experimentally demonstrate a simple and efficient scheme to achieve a symmetric 40-Gb/s long-reach (LR) time-division-multiplexed PON by using four wavelength-division-multiplexed 10-Gb/s external on-off keying format channels to serve as the optical transmitter for downstream and upstream traffic simultaneously. Moreover, the system performance of LR transmission and split ratio have also been analyzed and discussed without dispersion compensation.
Utilizing Self-Seeding RSOA with Faraday Rotator Mirror for Colorless Access Network
(2014-01-01)
Wu, Yu-Fu
;
Sun, Jinu-Yu
;
Chow, Chi-Wai
;
Yeh, Chien-Hung
;
光電工程學系
In this paper, we propose and demonstrate a self-seeding 1.2 GHz RSOA-based laser by employing 3.5 Gbit/s orthogonal-frequency-division-multiplexing quadrature-amplitude-modulation (OFDM-QAM) with bit-loading algorithm for upstream traffic in a colorless WDM-PON access. To achieve 3.5 Gbit/s traffic data rate and accomplish the forward error correction (FEC) threshold [bit error rate (BER) = 3.8x10(-3)], a Faraday rotator mirror (FRM) is used to perform self-seeding operation in this experiment. Here, the power penalty is about 2.59 dB at the wavelength of 1550.0 nm wavelength in a 20 km single mode fiber (SMF) transmission. Moreover, the measured BER performances of proposed laser are also discussed and analyzed, while the fiber mirror (FM) is used to replace the FRM in this experiment.