Browsing by Author "Liaw, Shien-Kuei"

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Analysis of Thermo-Optic Tunable Dispersion-Engineered Short-Wavelength-Pass Tapered-Fiber Filters
(2009-07-01)
Chou, Sen-Yih
;
Hsu, Kuei-Chu
;
Chen, Nan-Kuang
;
Liaw, Shien-Kuei
;
Chih, Yu-Syun
Thermo-optic tunable short-wavelength-pass tapered-fiber filters based on fundamental-mode cutoff mechanism are realized experimentally and analyzed theoretically. The effects of material and waveguide dispersion are investigated and the optimal tapered fiber structures for attaining high-spectral cutoff slope and high-rejection efficiency are determined.
Bandpass Filter With Variable Bandwidth Based on a Tapered Fiber With External Polymer Cladding
(2009-07-01)
Hsu, Kuei-Chu
;
Chen, Nan-Kuang
;
Chou, Sen-Yih
;
Liaw, Shien-Kuei
;
Lai, Yinchieh
A thermo-optical bandwidth-variable fiber-based bandpass filter is experimentally and theoretically demonstrated by simply utilizing a tapered standard single-mode fiber covered with a dispersive polymer layer. The 3-dB spectral bandwidth can be tuned from 250 to 500 nm with the filter center wavelength around 1 mu m.
Bandwidth-Variable Bandpass Filter based on Dispersion Engineered Tapered Fiber with External Polymer Cladding
(2009)
Hsu, Kuei-Chu
;
Chen, Nan-Kuang
;
Chou, Sen-Yih
;
Liaw, Shien-Kuei
;
Lai, Yinchieh
A simple thermo-optic bandwidth-variable fiber-based bandpass filter is demonstrated by using a tapered standard single mode fiber covered with a dispersive polymer layer. The 3 dB spectral bandwidth can be tuned from 250 rim with a Gaussian shape to 500 nm with a flat-top shape. (C) 2008 Optical Society of America
Highly efficient femtosecond pulse stretching by tailoring cavity dispersion in erbium fiber lasers with an intracavity short-pass edge filter
(2011-08-15)
Chen, Nan-Kuang
;
Liu, Feng-Zhou
;
Chuang, Hsiu-Po
;
Lai, Yinchieh
;
Yang, Shang-Da
We demonstrate highly efficient pulse stretching in Er(3+)-doped femtosecond mode-locked fiber lasers by tailoring cavity dispersion using an intracavity short-pass edge filter. The cavity dispersion is preset at around zero to obtain the shortest pulsewidth. When the cutoff wavelength of the short-pass edge filter is thermo-optically tuned to overlap the constituting spectral components of mode-locked pulses, large negative waveguide dispersion is introduced by the steep cutoff slope and the total cavity dispersion is moved to normal dispersion regime to broaden the pulsewidth. The time-bandwidth product of the mode-locked pulse increases with the decreasing temperature at the optical liquid surrounding the short-pass edge filter. Pulse stretch ratio of 3.53 (623.8fs/176.8fs) can be efficiently achieved under a temperature variation of 4 degrees C. (C) 2011 Optical Society of America
Influence of depressed-index outer ring on evanescent tunneling loss in tapered double-cladding fibers
(2008-08-01)
Chen, Nan-Kuang
;
Hsu, Kuei-Chu
;
Liaw, Shien-Kuei
;
Lai, Yinchieh
;
Chi, Sien
A tapered fiber with a depressed-index outer ring is fabricated and dispersion engineered to generate a widely tunable (1250-1650 nm) fundamental-mode leakage loss with a high cutoff slope (-1.2 dB/nm) and a high attenuation for stop band (> 50 dB) by modification of both waveguide and material dispersions. The higher cutoff slope is achieved with a larger cross angle between the two refractive index dispersion curves of the tapered fiber and surrounding optical liquids through the use of depressed-index outer ring structures in double-cladding fibers. (c) 2008 Optical Society of America.
Remote-Pumped Integrated Real-Time Monitoring in a WDM-PON
(2008)
Liaw, Shien-Kuei
;
Hong, Kuan-Lun
;
Shei, Yao-Sheng
;
Chen, Nan-Kuang
;
Hsu, Kuei-Chu
A proposed configuration to monitor a wavelength division multiplexing (WDM) passive optical network (PON) with high quality in service is presented. This system composes of fiber Bragg gratings, an 1x4 optical switch and an optical time domain reflectometry to diagnose the broken points in real time. The scheme could simultaneously detect multi-optical network units in a WDM-PON. Remote pump integrated residual pumping reused function is implemented. Broken points in different optical paths can be detected simultaneously even the distances to central office are identical. Bit error rate testing is verified with small power penalty, making it an ideal solution for real-time monitoring in a WDM-PON.
Wideband tunable Gaussian-shaped spectral filters based on dispersion engineering
(2009-08-01)
Hsu, Kuei-Chu
;
Chen, Nan-Kuang
;
Chou, Sen-Yih
;
Liaw, Shien-Kuei
;
Lai, Yinchieh
Optical liquids can be used to engineer the dispersion characteristics of fibers by serving as the core or cladding to attain fundamental-mode cutoff effect. The short-/long-pass fiber filters are so made and concatenated to achieve widely thermo-optic tunable Gaussian-shaped spectral filters. The proposed wideband tunable Gaussian-shaped spectral filter provides a potential technique in application to high resolution bio-imaging. (C) 2009 Elsevier Inc. All rights reserved.