Browsing by Author "Lin, Kuei-Huei"

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12 GHz passive harmonic mode-locking in a 1.06 mu m semiconductor optical amplifier-based fiber laser with figure-eight cavity configuration
(2013-03-15)
Chen, Hou-Ren
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Lin, Kuei-Huei
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Tsai, Chih-Ya
;
Wu, Hsiao-Hua
;
Wu, Chih-Hsuan
We report the generation of passively harmonic mode-locked pulses using a 1.06 mu m semiconductor optical amplifier (SOA) in a figure-eight laser configuration operated in the all-normal-dispersion regime. Different orders of harmonic mode-locking can be obtained from 30 MHz to 12.02 GHz by changing the injection current of the SOA from 80 to 660 mA together with the adjustment of polarization controllers. The highest pulse repetition rate increases almost linearly with the SOA current. As SOA current is set to 660 mA, we obtain the intracavity power of 46 mW at the highest repetition rate of 12.02 GHz, corresponding to the 1202th harmonic of the fundamental mode-locking frequency. To our best knowledge, this is the lowest intracavity power to generate the highest repetition rate with a passively mode-locked laser in the all-normal-dispersion regime. (C) 2013 Optical Society of America
Detection of chlorophylls in spores of seven ferns
(2017-03-01)
Tseng, Mei-Hwei
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Lin, Kuei-Huei
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Huang, Yi-Jia
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Chang, Ya-Lan
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Huang, Sheng-Cih
Fern spores were traditionally classified into chlorophyllous (green) and nonchlorophyllous (nongreen) types based on the color visible to the naked eye. Recently, a third type, "cryptochlorophyllous spores", is recognized, and these spores are nongreen under white light but contain chlorophylls. Epifluorescence microscopy was previously used to detect chlorophylls in cryptochlorophyllous spores. In addition to epifluorescence microscopy, current study performed some other approaches, including spore-squash epifluorescence, absorption spectra, laser-induced fluorescence emission spectra, thin layer chromatography (TLC), and ultra-high performance liquid chromatography with ultraviolet and mass spectrometric detection (UHPLC-UV-MS) in order to detect chlorophylls of spores of seven ferns (Sphaeropteris lepifera, Ceratopteris thalictroides, Leptochilus wrightii, Leptochilus pothifolius, Lepidomicrosorum buergerianum, Osmunda banksiifolia, and Platycerium grande). Destructive methods, such as TLC and UHPLC-UV-MS, successfully detected chlorophylls inside the spores when their signals of red fluorescence under epifluorescence microscope were masked by spore wall. Although UHPLC-UV-MS analysis was the most sensitive and reliable for determining the chlorophylls of spores, spore-squash epifluorescence is not only reliable but also cost- and time-effective one among our study methods. In addition, we first confirmed that Lepidomicrosorium buergerianum, Leptochilus pothifolius, Leptochilus wrightii, and Platycerium grande, produce cryptochlorophyllous spores.
Generation of chirped long-period gratings in photonic crystal fiber using a constant period corrugated device
(2007)
Chen, Hou-Ren
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Lin, Kuei-Huei
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Lin, Ja-Hon
;
Liu, Wen-Fung
;
Hsieh, Wen-Feng
Chirped long-period fiber gratings (LPGs) are generated in bended photonic crystal fiber (PCF) by using a constant period corrugated device. As the chirping increases, the rejection bandwidth in the transmission spectra of LPGs also increases. Spectral modulation peaks are observed and the modulation depth is increased with the amount of chirping. A chirped dual LPG with rejection bandwidth of about 300 run has been obtained in a bended PCF.
Generation of supercontinuum bottle beam using an axicon
(2007-03-19)
Lin, Ja-Hon
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Wei, Ming-Dar
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Liang, Hui-Hung
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Lin, Kuei-Huei
;
Hsieh, Wen-Feng
A supercontinuum bottle beam was successfully produced by focusing a supercontinuum laser beam after passing through an axicon. The supercontinuum radiation was generated from a microstructured fiber pumped by a self-kerr-lensmode-locked femtosecond Ti: sapphire laser. The cross-section intensity distributions of the generated bottle were recorded by a beam profiler. Using the line filters to select different central wavelengths, the different colors of bottle beams show slightly different bottle ranges and diameters due to the dispersion of axicon and focusing lens. The results consist with the theoretical prediction using the Fresnel-Kirchhoff's formula in considering an incident Gaussian beam. (c) 2007 Optical Society of America.
High-power passively continuous-wave and Q-switching mode-locked Nd:LuVO4 laser by few-layer graphene-oxide films
(2016-12-01)
Chen, Hou-Ren
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Tsai, Chih-Ya
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Cheng, Hsin-Ming
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Lin, Kuei-Huei
;
Chen, Chyong-Hua
Using a series of different concentration polymer-free graphene oxide (GO) films as saturable absorbers (SAs), we demonstrate high-power passively continuous-wave modelocking (CW-ML) and Q-switching mode-locking (QS-ML) for a Nd: LuVO4 laser at 1 mu m. CW-ML pulses of 6.62 ps with maximum output power of 3.89 W have been achieved to give the highest pulse peak power of 4.85 kW and pulse energy of 32.14 nJ under 15-W pumping by using SAs of 84.4% transmittance. Using SAs with a lower transmittance having a larger modulation depth of 75.9% and 63.4%, we obtain both the CW-ML pulses of 4.85-ps and QSML pulses with 2.73 W and 1.92 W output powers, respectively. (C) 2016 Optical Society of America
High-power, passively mode-locked Nd:GdVO(4) laser using single-walled carbon nanotubes as saturable absorber
(2011-04-01)
Chen, Hou-Ren
;
Wang, Yong-Gang
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Tsai, Chih-Ya
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Lin, Kuei-Huei
;
Chang, Teng-Yao
We use a new (to our knowledge) fabrication method of a single-walled carbon nanotube (SWCNT) absorber without polymer to sustain high-power illumination. Using a series of saturable absorbers (SAs) incorporating different amounts of SWCNTs, we demonstrate mode-locking for a Nd:GdVO(4) laser in the 1 mu m spectral range. Continuous-wave mode-locking (CWML) pulses with a maximum output power of 3.6 W at 1063 nm and high noise extinction of 61 dB has been achieved to give the highest pulse peak power of 3.6 kW and pulse energy of 30 nJ under 15 W pumping. To our knowledge, this is the highest CWML output power with SWCNT-SAs reported. The measured nonlinear absorption of the SWCNT-SAs shows a modulation depth of similar to 3% with subpicosecond recovery time. (C) 2011 Optical Society of America
High-power, passively mode-locked Nd:GdVO4 laser using single-walled carbon nanotubes as saturable absorber
(2011-04-01)
Chen, Hou-Ren
;
Wang, Yong-Gang
;
Tsai, Chih-Ya
;
Lin, Kuei-Huei
;
Chang, Teng-Yao
We use a new (to our knowledge) fabrication method of a single-walled carbon nanotube (SWCNT) absorber without polymer to sustain high-power illumination. Using a series of saturable absorbers (SAs) incorporating different amounts of SWCNTs, we demonstrate mode-locking for a Nd:GdVO4 laser in the 1 mu m spectral range. Continuous-wave mode-locking (CWML) pulses with a maximum output power of 3.6 W at 1063 nm and high noise extinction of 61 dB has been achieved to give the highest pulse peak power of 3.6 kW and pulse energy of 30 nJ under 15 W pumping. To our knowledge, this is the highest CWML output power with SWCNT-SAs reported. The measured nonlinear absorption of the SWCNT-SAs shows a modulation depth of similar to 3% with subpicosecond recovery time. (C) 2011 Optical Society of America
High-quality and Large-size Topological Insulator Bi2Te3-Gold Saturable Absorber Mirror for Mode-Locking Fiber Laser
(2016-12-05)
Chen, Hou-Ren
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Tsai, Chih-Ya
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Cheng, Hsin-Ming
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Lin, Kuei-Huei
;
Yen, Po-Hsiu
A novel high-quality, large-size, reflection-type topological insulator Bi2Te3-Gold (BG) film-based nonlinear optical modulator has been successfully fabricated as a two-dimensional saturable absorber mirror (SAM) by pulsed laser deposition (PLD). This BG-SAM possesses saturation fluence of 108.3 mu J/cm(2), modulation depth (Delta R) of 6.5%, non-saturable loss of 38.4%, high damage threshold above 1.354 mJ/cm(2) and excellent uniformity providing for the generation of passive mode-locked (ML) pulses for erbium-doped fiber lasers (EDFLs) on a large sample area. Under 124 mW 976 nm pumping, We obtained 452-fs continuous-wave ML pulses with pulse energy of 91 pJ and full width at halfmaximum (FWHM) of 6.72-nm from this EDFL. The results clearly evidence that the PLD is an efficient method for fabricating BG-SAM that is suitable for a compact ultrafast ML fiber laser system.
Investigation of Graphene Dispersion From Kelly Sideband in Stable Mode-Locked Erbium-Doped Fiber Laser by Few-Layer Graphene Saturable Absorbers
(2015-11-01)
Chen, Hou-Ren
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Tsai, Chih-Ya
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Chang, Ching-Yang
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Lin, Kuei-Huei
;
Chang, Chen-Shiung
In this paper, stable passively mode-locked fiber lasers (MLFLs) constructed using graphene saturable absorbers (SAs) with different layer numbers of similar to 1 to similar to 15 have been reported. The flat linear transmission spectrum in the range from 1540 to 1580 nm without any distinct absorption peak implies that the graphene SAs exhibit low dispersion in this region. Therefore, stable soliton-like pulses are generated because of negative dispersion provided by the fiber laser cavity, which requires no additional single-mode fiber (SMF) for dispersion compensation. Power-dependent transmission measurements show that the saturation intensity ranges from 1.2 to 3.2 MW/cm(2) and that the modulation depth (MD) of the graphene SAs increases with the number of graphene layers. All the samples were observed to easily mode-lock the laser with a stable mode-locking state persistently operated over hours. By analyzing the soliton Kelly sidebands, we deduced the group delay dispersion (GDD) for different layers of the graphene. The calculated results show that the variation of sample GDD is within the calculation error, indicating that the GDD of graphene is small to be negligible. This result is consistent with the experimental results reported by Chang et al. [Appl. Phys. Lett. 97, 211102 (2010)] using the phase-shift method. This study demonstrates that different layers graphene SAs have different MD contributions to the generation of laser pulses with different pulse widths.
Passive mode locking of ytterbium- and erbium-doped all-fiber lasers using graphene oxide saturable absorbers
(2014-06-02)
Chen, Hou-Ren
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Tsai, Chih-Ya
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Cheng, Hsin-Ming
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Lin, Kuei-Huei
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Hsieh, Wen-Feng
Broadband graphene oxide/PVA films were used as saturable absorbers (SAs) for mode locking erbium-doped fiber laser (EDFL) and ytterbium-doped fiber laser (YDFL) at 1.06 mu m and 1.55 mu m. They provide modulation depths of 3.15% and 6.2% for EDFL and YDFL, respectively. Stable self-starting mode-locked pulses are obtained for both lasers, confirming that the graphene oxide is cost-effective. We have generated mode-locked pulses with spectral width, repetition rate, and pulse duration of 0.75 nm, 9.5 MHz, and 2.7 ps. This is the shortest pulse duration directly obtained from an all-normal-dispersion YDFL with graphene-oxide saturable absorber. (C) 2014 Optical Society of America
Q-switched and mode locked pulses generated from c-cut Nd:LuVO4
(2009)
Song, Kun-Tai
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Lin, Ja-Hon
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Chen, Hou-Ren
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Lin, Kuei-Huei
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Hsieh, Wen-Feng
Q-switched and mode locked pulses have been demonstraed in c-cut Nd center dot LuVO4 laser Using 80% initial transmittance of Cr4+ YAG and output coupler with 70% refleactane, large pulse energy of about 112 mu J has been demonstrated at 18 W pumping.
Stable and Self-Starting Passively Mode-Locked Fiber Laser for 1.06 mu m and 1.55 mu m by Using Graphene Oxide Saturable Absorber
(2013)
Chen, Hou-Ren
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Tsai, Chih-Ya
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Lin, Kuei-Huei
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Wang, Jing-Yun
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Hsieh, Wen-Feng
Graphene oxide/PVA film is used as saturable absorber for mode locking erbium-doped fiber laser and ytterbium-doped fiber laser. It provides modulation depths of 2.6% and 6% at 1.06 mu m and 1.55 mu m, respectively. Stable mode-locked pulses are obtained for both lasers confirming that graphene oxide is cost- effective for 1.06-mu m and 1.55-mu m pulse generations.
Stable Optical Clock Generation in SOA-Based Fiber Lasers with Figure-Eight Cavity
(2013)
Wang, Jing-Yun
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Lin, Kuei-Huei
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Chen, Hou-Ren
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光電工程學系
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Department of Photonics
Stable optical clocks are obtained from 1.3-mu m and 1.5-mu m SOA-based fiber lasers using passive technology. The waveforms depend on SOA currents, and the repetition rates can be tuned by varying the relative length of sub-cavities.
Stable passive optical clock generation in SOA-based fiber lasers
(2015-02-15)
Wang, Jing-Yun
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Lin, Kuei-Huei
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Chen, Hou-Ren
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光電工程學系
;
Department of Photonics
Stable optical pulse trains are obtained from 1.3-mu m and 1.5-mu m semiconductor optical amplifier (SOA)-based fiber lasers using passive optical technology. The waveforms depend on SOA currents, and the repetition rates can be tuned by varying the relative length of sub-cavities. The output pulse trains of these SOA-based fiber lasers are stable against intracavity polarization adjustment and environmental perturbation. The optical clock generation is explained in terms of mode competition, self-synchronization, and SOA saturation. Without resorting to any active modulation circuits or devices, the technology used here is simple and may find various applications in the future. (C) 2015 Optical Society of America
Stable Q-switched mode-locked Nd3+:LuVO4 laser by Cr4+:YAG crystal
(2008-10-13)
Lin, Ja-Hon
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Chen, Hou-Ren
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Hsu, Hsin-Han
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Wei, Ming-Dar
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Lin, Kuei-Huei
In use of saturable Cr4+:YAG crystals, we have demonstrated the stable Q-switched and mode-locked (QML) operation of the Nd:LuVO4 laser. The operation range of QML in use of the Cr4+:YAG is larger than that use of SESAM and NLM. The obtained shape of Q-switched envelope, repetition rate and pulse energy are demonstrated to depend on the initial transmittance of the Cr4+:YAG and reflectivity of the output coupler. Using R = 60% and T-0 = 40%, the highest pulse energy of 77 mu J of each Q-switched envelope, and the highest peak power about 200 kW of Q-switched mode-locked pulses can be obtained at 15 W pump power. It demonstrate the superior characteristic of the Nd:LuVO4 crystal. (C) 2008 Optical Society of America
Stress-Induced Versatile Tunable Long-Period Gratings in Photonic Crystal Fibers
(2008-09-01)
Chen, Hou-Ren
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Lin, Kuei-Huei
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Lin, Ja-Hon
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Hsieh, Wen-Feng
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光電工程學系
We report a method for generating versatile tunable long-period gratings (LPGs) in photonic crystal fibers (PCFs). The central wavelength and rejection bandwidth of LPGs can be tuned over a broad spectral range with adjustable transmission loss. Spectral fringes with uneven spacing are observed in chirped LPGs, depending on the interaction length and the amount of chirping between the two ends of the LPG, and can be removed by reducing the chirping and increasing the grating length. By utilizing a stress-induced LPG, gain flattening of an erbium-doped fiber amplifier has also been demonstrated.
Supercontinnum generation in a microstructured optical fiber by picosecond self Q-switched mode-locked Nd : GdVO4 laser
(2006)
Lin, Ja Hon
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Lin, Kuei-Huei
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Hsieh, Wen-Feng
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光電工程學系
;
Department of Photonics
An effective supercontinuum generation is demonstrated by injecting picosecond self Q-switched mode-locked Nd:GdVO4 laser pulses into an 1 m long microstructured fiber (MF) near the longer zero-dispersion wavelength of the dual zero-dispersion points.
Ultrabroadband Tunable Long-Period Fiber Grating for Stress Sensing and Optical Filtering
(2017-01-01)
Chen, Hou-Ren
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Kuan, Wen-Hsuan
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Lin, Kuei-Huei
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光電工程學系
;
Department of Photonics
Both constant-period and broadband chirped long-period gratings (LPGs) are generated in photonic crystal fibers (PCFs) by using a constant period V-grooved plate or solenoidal wiring device. The central wavelength and rejection bandwidth of LPGs can be tuned over a broad spectral range with adjustable transmission loss. In contrast to the conventional LPG sensors with longitudinal stretch or compression, the PCF-LPGs can be used for sensing the lateral pressure. They have potential applications for stress sensors and versatile optical filters.
Ultrashort Pulse Compression for Mode-Locked Ti:Sapphire Laser by Using a Tapered Fiber and Grating Pair
(2010-05-01)
Lin, Ja-Hon
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Taso, Chih-Chieh
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Hsu, Kuei-Chu
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Lin, Kuei-Huei
;
Lai, Yinchieh
Extracavity pulse compression for pulses from an 82 MHz mode-locked Ti: sapphire laser is demonstrated by utilizing a tapered fiber of 1 mu m in diameter and 10 mm in length. Group velocity dispersion of the tapered fiber is calculated, which shows two zero dispersion wavelengths locating at 545 and 1250 nm, respectively. The nonlinear coefficient gamma of the tapered fiber is estimated to be 733 (W(-1) km(-1)) at 880 nm wavelength. With 80 fs input pulses at 880 nm center wavelength, the optical bandwidth is broadened beyond 22 THz by the tapered fiber. After dispersion compensation by a grating pair with 1.45 cm separation, 26 fs output pulses are obtained. One-third pulse compression ratio has been experimentally demonstrated in this work for center wavelengths ranging from 720 to 880 nm. (C) 2010 The Japan Society of Applied Physics