Browsing by Author "Chang, Yuan-Chia"

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2.6 Tbit/s On-Chip Optical Interconnect Supporting Mode-Division-Multiplexing and PAM-4 Signal
(2018-06-01)
Hsu, Yung
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Chuang, Chun-Yen
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Wu, Xinru
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Chen, Guan-Hong
;
Hsu, Chin-Wei
In this letter, we combine the use of dense-wavelength-division-multiplexing and mode-division-multiplexing (MDM) with advanced-modulation formats for on-chip optical interconnects. A three-mode MDM multiplexer (MUX) and de-multiplexer (DEMUX) was designed and used. Each wavelength carrier had an aggregate data rate of 192-Gbit/s using 4-level pulse-amplitude-modulation. The mode crosstalk of the MDM MUX/DEMUX was measured to he below -20 dB in the 40-nm wavelength band from 1520 to 1560 nm. Fourteen wavelength channels are multiplexed and successfully transmitted with an aggregate transmission capacity of 2.6 Tbit/s (14 wavelengths x 3 modes x 64 Gbit/s) with all channels satisfying the hard-decision forward-error-correction threshold. Numerical analysis of the mode crosstalk is also performed.
Based on Silicon-micro-ring-resonator and Triple-ring Cavity for Stable and Tunable Erbium Fiber Laser
(2018-01-01)
Hsu, Yung
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Chang, Yuan-Chia
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Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Chen, Jing-Heng
In this paper, a stable and wavelength-switchable erbium-doped fiber (EDF) laser by utilizing the silicon-micro-ring-resonator (SMRR) and multiple-fiber-ring (MFR) scheme is demonstrated. Here, three optical couplers (CPs) can construct the passive MFR in the proposed and achieve single-longitudinal-mode (SLM) output simultaneously. The SMRR is used inside a fiber cavity as mode restrict element for wavelength-tuning. By properly adjusting the polarization controllers (PCs), the output wavelength can be tuned in a wavelength range of 1544.35 to 1564.10nm with a similar to 2.0 nm tuning step. Hence, the proposed EDF laser can reach the characteristics of SLM output, 35 kHz output linewidth, and optical single-to-noise ratios (OSNRs) of > 54.9 dB. In addition, the output stabilities of the power and wavelength in the proposed EDF laser are also discussed.
Compact 84 GHz passive mode-locked fiber laser using dual-fiber coupled fused-quartz microresonator
(2017-10-01)
Liu, Tze-An
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Hsu, Yung
;
Chow, Chi-Wai
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Chuang, Yi-Chen
;
Ting, Wei-Jo
We propose and demonstrate a compact and portable-size 84-GHz passive mode-locked fiber laser, in which a dual-fiber coupled fused-quartz microresonator is employed as the intracavity optical comb filter as well as the optical nonlinear material for optical frequency comb generation. About eight coherent optical tones can be generated in the proposed fiber laser. The 20-dB bandwidth is larger than 588 GHz. The full-width halfmaximum pulse-width of the proposed laser is 2.5 ps. We also demonstrate the feasibility of using the proposed passive mode-locked fiber laser to carry a 5-Gbit/s on-off-keying signal and transmit over 20-km standard single mode fiber. A 7% forward error correction requirement can be achieved, showing the proposed fiber laser can be a potential candidate for fiber-wireless applications. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Employment of silicon-micro-ring resonator and compound-ring architecture for stable and tunable single-longitudinal-mode fiber laser
(2018-09-01)
Hsu, Yung
;
Yeh, Chien-Hung
;
Cheng, Hao-Yun
;
Chang, Yuan-Chia
;
Chow, Chi-Wai
In this work, a wavelength-switchable erbium-doped fiber (EDF) glasses-type compound-ring (GTCR) laser with stable single-longitudinal-mode (SLM) oscillation is proposed and presented. In the experiment, to accomplish wavelength-tunable operation, a silicon-micro-ring-resonator (SiMRR) is utilized inside the ring cavity, when the birefringent loss of EDF laser is adjusted properly. Moreover, the GTCR configuration is proposed to as the mode-filter for suppressing the multi-longitudinal-mode (MLM) to achieve the SLM oscillation. Here, the measured linewidth of output wavelength is 61 kHz. The output stabilities of the proposed SiMRR EDF compound-ring laser are also discussed experimentally. (C) 2018 Elsevier Ltd. All rights reserved.
Metal substituted pyrochlore phase LixLa2-xCe1.8Ru0.2O7- (x=0.0-0.6) as an effective catalyst for oxidative and auto-thermal steam reforming of ethanol
(2019-03-21)
Hsieh, Ho-Chen
;
Chang, Yuan-Chia
;
Tsai, Ping-Wen
;
Lin, Yen-Yu
;
Chuang, Yu-Chun
Pyrochlore phase LixLa2-xCe1.8Ru0.2O7- (x = 0.0-0.6) [LLCRO] substituted by Li and Ru in A and B sites was synthesized and studied for performance in oxidative steam and auto-thermal reforming of ethanol (OSRE, ATR). The samples were characterized by powder X-ray diffraction (PXRD), X-ray absorption spectroscopy (XAS), and X-ray photoelectron spectroscopy (XPS) to examine the effect of substituted Li+ and Run+ on OSRE performance. The results indicated that the substituted Li ions modified the oxidation states of Ru and Ce in LLCRO, which led to oxygen vacancies/mobility and played an important role in the catalytic performance of OSRE. Using LLCRO as the catalyst and supported by Al2O3, La2Zr2O7 (LZO) was investigated for its hydrogen production performance. The catalytic stability of the LLCRO (x = 0.6)/LZO catalysts was tested at 350 degrees C under oxidative steam conditions (OSRE) and showed a stable ethanol conversion and hydrogen production (X-EtOH = 98(3)%; S-H2 = 95(3)%). Under autothermal conditions (ATR), the LLCRO (x = 0.6) catalyst supported by LZO exhibited a stable catalytic performance with an average ethanol conversion and hydrogen selectivity of 90(3)% and 71(4)%, respectively. Carbon deposition was significantly suppressed during the OSRE and ATR processes on LLCRO (x = 0.6) catalysts supported by LZO, whereas, a significant carbon deposition was observed for LLCRO (x = 0.6)/Al2O3 as the catalyst. These results indicate that LLCRO (x = 0.6) supported by LZO is an effective catalyst for hydrogen production. The enhanced activity was attributed to the effectively suppressed carbon deposition and the sintering of highly dispersed Ru ions in the LLCRO catalyst, which may be due to the strong binding between the catalyst and LZO.
Oxidative steam reforming of ethanol over MxLa2-xCe1.8Ru0.2O7-delta (M = Mg, Ca) catalysts: effect of alkaline earth metal substitution and support on stability and activity
(2019-12-02)
Hsieh, Ho-Chen
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Tsai, Ping-Wen
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Chang, Yuan-Chia
;
Weng, Sheng-Feng
;
Sheu, Hwo-Shuenn
Alkaline earth metal substitutions on the A-site of pyrochlore oxide MxLa2-xCe1.8Ru0.2O7-delta (M = Mg, Ca) were studied as catalyst materials for oxidative/autothermal steam reforming of ethanol (OSRE/ATR). The as-prepared oxides were synthesized by a combustion method and characterized using powder X-ray diffraction (PXRD), and X-ray photoelectron and absorption spectroscopy (XPS and XAS). PXRD Rietveld analysis and elemental analysis (ICP-AES) support the formation of a pyrochlore-type structure (space group Fd3m) with a distorted coordination environment. The substitution of Mg²⁺ and Ca²⁺ ions affects the oxidation states of Ce^4+/3+ and Ruⁿ⁺ ions and creates oxygen vacancies, which leads to enhanced catalytic activity and reduced ethylene selectivity. A long-term stability test showed optimized catalysts Mg0.3La1.7Ce1.8Ru0.2O7-delta and Ca0.2La1.8Ce1.8Ru0.2O7-delta with SH2 = 101(1)% and SH2 = 91(2)% under OSRE conditions. The initial operation temperatures were lower than that of the unsubstituted catalyst La2Ce1.8Ru0.2O7-delta. Catalysts supported on La2Zr2O7 showed stable OSRE/ATR performance and low carbon deposition compared to catalysts supported on Al2O3. We ascribe the enhanced activity to well-dispersed alkaline earth metal and Ru ions in a solid solution structure, synergistic effects of (Mg, Ca)²⁺/Ce^3+/4+/Ruⁿ⁺ ions, and a strong catalyst-support interaction that optimized the ethanol conversion and hydrogen production.
Polarization-Multiplexed Rolling Shutter Demodulation in Mobile-Phone Based Visible Light Communication
(2018-01-01)
Chang, Yuan-Chia
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Chen, Chia-Wei
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Liu, Yen-Chun
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Shiu, Ruei-Jie
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Chow, Chi-Wai
We propose and demonstrate using polarization-multiplexing of rolling-shutter-effect (RSE) based visible-light-communication (VLC) to increase the transmission capacity. Experimental net data rate of 11.52 kbit/s was achieved at typical room illuminance of 500 lux.
Silicon-Micro-Ring Resonator-Based Erbium Fiber Laser With Single-Longitudinal-Mode Oscillation
(2018-06-01)
Yeh, Chien-Hung
;
Cheng, Hao-Yun
;
Chang, Yuan-Chia
;
Chow, Chi-Wai
;
Chen, Jing-Heng
In this paper, we propose and experimentally illustrate a wavelength-switchable erbium-doped fiber (EDF) dual-ring (DR) laser with stable single-longitudinal-mode (SLM) oscillation. In the experiment, a silicon-micro-ring-resonator (SiMRR) is applied in the proposed DR cavity for tuning different output wavelengths, when the birefringence loss is adjusted correctly. To compress the densely multilongitudinal-mode oscillations, the DR scheme together with a 2-m unpumped EDF-based saturable absorber is acted as the mode filter. The DR also can produce self-injection loop for an SLM operation. The wavelength tunability is between 1532.61 to 1557.98 nm and the measured 3-dB output linewidth is similar to 22.5 kHz. Moreover, the output stabilizations of the proposed SiMRR-based EDF DR laser are also analyzed and discussed.
Silicon-on-Insulator (SOI) based Polarization-Exchanger using Asymmetric Directional Coupler
(2018-01-01)
Peng, Ching-Wei
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Chang, Yuan-Chia
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Cheng, Ming-Wei
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Hsu, Yung
;
Wei, Liang-Yu
We propose an silicon-on-insulator (SOI) based polarization-exchanger using bi-level-tapers and asymmetric-directional-couplers. Signal from transverse-electric (TE) polarization can be switched to transverse-magnetic (TM) polarization and vice versa. Crosstalk <= -25dB is observed in 40nm wavelength window.
Stabilized single-longitudinal-mode erbium fibre laser employing silicon-micro-ring resonator and saturable absorber
(2018-07-01)
Hsu, Yung
;
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
Chang, Yuan-Chia
;
Cheng, Hao-Yun
In the paper, a wavelength-tunable erbium-doped fiber (EDF) ring laser with stable single-longitudinal-mode (SLM) oscillation is proposed and investigated. Here, a silicon-microring-resonator can be applied in a laser cavity for tuning wavelength in the C-band range. To complete the SLM oscillation, an unpumped EDF-based saturable absorber is used to act as ultra-narrowband filter for suppressing other oscillation modes. Additionally, the output stabilities of power and wavelength in the proposed EDF ring laser are also executed and discussed.