Browsing by Author "Hsiang, Wei-Wei"

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A new dispersioin measurement apparatus by a periodic wavelengh-scanning pulse laser
(2009)
Jyu, Siao-Shan
;
Liu, Shiou-Fong
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
A new fiber group velocity dispersion (GVD) measurement method has been reported and demonstrated by using a periodic wavelength-scanning pulse laser such as an asynchronously modelocked Er-fiber soliton laser and simple RF spectral measurement.
A simple group velocity dispersion measurement method by RF spectral periodic pulse timing variation characterization
(2009)
Liu, Shiou-Fong
;
Jyu, Siao-Shan
;
Chang, Hon-Chieh
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
By measuring the dispersion-induced periodic pulse timing variation with a wavelength-swept pulse light source and a RF spectrum analyzer, the fiber group velocity dispersion can be determined with excellent accuracy. (C)2009 Optical Society of America
Asynchronous Harmonic Mode Locking in an All-Normal Dispersion Yb-Doped Fiber Laser
(2013-02-01)
Wang, Sheng-Min
;
Jyu, Siao-Shan
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
We present detailed experimental and theoretical results to demonstrate the possibility of asynchronous harmonic mode locking in an all-normal dispersion fiber laser. In contrast to asynchronous soliton mode-locking operation in the anomalous dispersion regime, more profound laser dynamics are found. The experimentally demonstrated 10-GHz asynchronous harmonic mode-locked Yb-doped fiber laser exhibits an excellent super-mode noise suppression ratio in the RF spectrum with picosecond output pulsewidth.
Direct observation of two-color pulse dynamics in passively synchronized Er and Yb mode-locked fiber lasers
(2011-11-21)
Hsiang, Wei-Wei
;
Chiao, Wei-Chih
;
Wu, Chia-Yi
;
Lai, Yinchieh
;
光電工程學系
We report direct experimental observation of interesting pulse synchronization dynamics in a cavity-combined Er and Yb mode-locked fiber lasers by measuring the relative position between the two-color pulses in the shared fiber section. The influence of the 1.03 mu m pulse on the 1.56 mu m single pulse as well as bound soliton pairs can be clearly identified as an effective phase modulation through the XPM effect with the walk-off effect taken into account. For the 1.56 mu m single pulse under synchronization, the dependence of the relative position variation and the center wavelength shift on the cavity mismatch detuning is found analogous to the typical characteristics of FM mode-locked lasers with modulation frequency detuning. Moreover, depending on the cavity mismatch, the passively synchronized 1.56 mu m bound soliton pairs are found to exhibit two different dynamical behaviors, i.e., phase-locked (in-phase) as well as non-phase-locked. The physical origins for these two kinds of bound soliton pairs are investigated experimentally by disclosing their locations with respective to the copropagating 1.03 mu m pulse. (C) 2011 Optical Society of America
Fiber Dispersion Measurement With a Swept-Wavelength Pulse Light Source
(2010-05-01)
Jyu, Siao-Shan
;
Liu, Shiou-Fong
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
A new fiber dispersion measurement method by utilizing a periodically swept-wavelength pulse light source is proposed and demonstrated. The periodic pulse timing variation of the pulse train induced by wavelength sweeping can be directly detected by a radio-frequency spectrum analyzer. Experiments by using an asynchronous mode-locked fiber soliton laser as the swept-wavelength pulse source have been successfully carried out to demonstrate the feasibility.
Laser dynamics and relative timing jitter analysis of passively synchronized Er- and Yb-doped mode-locked fiber lasers
(2014-07-01)
Wu, Shang-Ying
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
;
Department of Photonics
Passively synchronized Er-doped and Yb-doped mode-locked fiber lasers with a master-slave configuration are theoretically investigated based on the pulse propagation model for simulating pulse collision in the common fiber section and on the master equation model for simulating laser dynamics. Computational results indicate that the central optical frequency of the slave Er laser will be shifted by the significant cross phase modulation (XPM) effect for the laser to become synchronized with the injected master Yb laser pulse train. Pulse duration change caused by fiber dispersion in the common fiber section will distort the ideal anti-symmetric characteristics of the XPM-induced frequency shift versus the relative timing position of the two color pulses. The relative timing jitter noises of the two synchronized lasers can be minimized by adjusting the relative pulse timing position, and the predicted dependence agrees well with the experimental observation. (C) 2014 Optical Society of America
Laser dynamics and relative timing jitter analysis of passively synchronized Er- and Yb-doped mode-locked fiber lasers
(2014-07-01)
Wu, Shang-Ying
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
;
光電工程研究所
Passively synchronized Er-doped and Yb-doped mode-locked fiber lasers with a master-slave configuration are theoretically investigated based on the pulse propagation model for simulating pulse collision in the common fiber section and on the master equation model for simulating laser dynamics. Computational results indicate that the central optical frequency of the slave Er laser will be shifted by the significant cross phase modulation (XPM) effect for the laser to become synchronized with the injected master Yb laser pulse train. Pulse duration change caused by fiber dispersion in the common fiber section will distort the ideal anti-symmetric characteristics of the XPM-induced frequency shift versus the relative timing position of the two color pulses. The relative timing jitter noises of the two synchronized lasers can be minimized by adjusting the relative pulse timing position, and the predicted dependence agrees well with the experimental observation. (C) 2014 Optical Society of America
Laser Dynamics of a 10 GHz 0.55 ps Asynchronously Harmonic Modelocked Er-Doped Fiber Soliton Laser
(2010-03-01)
Hsiang, Wei-Wei
;
Chang, Hon-Chieh
;
Lai, Yinchieh
;
光電工程學系
;
Department of Photonics
Laser dynamics of a 10 GHz 0.55 ps asynchronously harmonic modelocked Er-doped fiber soliton laser are investigated both theoretically and experimentally. Theoretical analyses based on the master equation model solved by the variational method have indicated that all the pulse parameters of the laser output will exhibit complicated slow periodic variations in the asynchronous soliton modelocking (ASM) mode. New experimental methods based on analyzing directly the RF spectra of the ASM laser output have been developed to accurately determine the sinusoidal variation of the pulse timing and the pulse center wavelength for the first time. It is found that the pulse center wavelength variation can be as large as 1 nm half-peak-to-peak and the pulse timing variation can be as large as 3 ps. The consistency among all the experimental data and theoretical prediction is carefully examined and the results indicate that the ASM pulse dynamics observed experimentally are in good agreement with those obtained from the theoretical analyses.
Laser Dynamics of Asynchronously Modelocked Fiber Soliton Lasers
(2008-01-01)
Hsiang, Wei-Wei
;
Chen, Ye-Chen
;
Chang, Hon-Chieh
;
Chen, Jye-Hong
;
Lai, Yinchieh
Laser dynamics of asynchronously modelocked Er-fiber soliton lasers is investigated theoretically and experimentally. The pulse parameters are found to exhibit complicated slow periodic variations and can be examined experimentally by analyzing the RF spectra. (C)2008 Optical Society of America
Methods of achieving linear index-change response for narrow-band fiber Bragg grating sequential writing
(2007-09-15)
Hsu, Kuei-Chu
;
Sheu, Lih-Gen
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
This investigation elucidates the refractive index-change response of the photosensitive optical fiber to exposed UV flux. The nonlinear U-V photosensitivity deforms the index profile of FBGs on the tail edges where the writing UV flux is low. Pre-UV treatment eliminates the nonlinear index-change response and ensures the linearity of the response of subsequent grating writing. A new method that involves interference between two unequal beams in a single writing scan is proposed and demonstrated to be able to improve the index profile and the spectral response of fabricated FBGs. The procedure is stable for writing weak fiber Bragg gratings with pre-designed index profiles. (c) 2007 Elsevier B.V. All rights reserved.
Passive synchronization between a self-similar pulse and a bound-soliton bunch in a two-color mode-locked fiber laser
(2009-07-01)
Hsiang, Wei-Wei
;
Chang, Chia-Hao
;
Cheng, Chien-Po
;
Lai, Yinchieh
;
光電工程學系
We report the first (to our knowledge) experimental observation of passive synchronization between a 1.03 mu m self-similar pulse and a 1.56 mu m bound-soliton bunch in a two-color mode-locked fiber laser. The self-similar pulse can form an effective potential well of several picoseconds to trap the copropagating bound solitons in the shared-fiber section. Such synchronization mechanism is supported by the experimental evidence of smaller time separation between the bound solitons under synchronization, In addition, the self-similar pulse and bound solitons can still remain locked under the periodic collision of another 1.56 mu m unlocked pulse train. (C) 2009 Optical Society of America
Passive Synchronization between Self-Similar Yb-Fiber and Stretched-Pulse Er-Fiber Mode-Locked Lasers
(2009-01-01)
Hsiang, Wei-Wei
;
Chang, Chia-Hao
;
Cheng, Chien-Po
;
Su, Hsin-Chia
;
Tsau, Seth
Passive synchronization is demonstrated between the self-similar Yb-fiber and the stretched-pulse Er-fiber mode-locked lasers. The pulse repetition rates of the two mode-locked lasers can keep locked when multiple-pulse bound states or periodic pulse collisions occur. (C)2009 Optical Society of America
Passively Synchronized Two-Color Polarization Additive Pulse Mode-Locked Fiber Lasers
(2008-01-01)
Hsiang, Wei-Wei
;
Cheng, Chien-Po
;
Chang, Chia-Hao
;
Fang, Chieh-Yu
;
Chang, Lien-Bee
Passive synchronization and polarization additive pulse mode-locking techniques are combined to generate simultaneously the 1.03 mu m and 1.53 mu m ultrashort pulses at the same pulse repetition rates from synchronized Yb-fiber and Er-fiber mode-locked lasers. (C)2008 Optical Society of America
Relative carrier-envelope phase stabilization of hybridly synchronized ultrafast Yb and Er fiber-laser systems with the feed-forward scheme
(2015-03-15)
Fong, Bo-Jyun
;
Lin, Wei-Ting
;
Wu, Shang-Ying
;
Peng, Jin-Long
;
Hsiang, Wei-Wei
Stabilization of the relative carrier-envelope (CE) phase for hybridly synchronized two-color fs Yb and Er fiber-laser systems is demonstrated for the first time by utilizing the feed-forward scheme based on an acousto-optic frequency shifter. The slow drift issues arising from the feed-forward scheme are solved by adding the in-loop relative CE frequency coarse stabilization via modulating the laser pump current. Sub-fs timing locking between the two-color pulses is still maintained due to the fast response and large locking range of hybrid synchronization. The approach provides an alternative way to obtain phase-stable synchronized two-color pulses with higher pulse energies. (C) 2015 Optical Society of America
Relative Timing Jitter of Passively Synchronized Er-doped and Yb-doped Mode-Locked Fiber Lasers
(2013)
Wu, Shang-Ying
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
;
Department of Photonics
The relative timing jitter of passively synchronized Er-doped and Yb-doped mode-locked fiber lasers is investigated. The predicted dependence on the relative timing position of the two-color pulses agrees nicely with the experimental observation.
Stabilizing a 10 GHz 0.8 ps asynchronously mode-locked Er-fiber soliton laser by deviation-frequency locking
(2006)
Hsiang, Wei-Wei
;
Lin, Chien-Yu
;
Sooi, Ng Kam
;
Lai, Yinchieh
;
光電工程學系
Without using high speed RF feedback electronics, long-term stabilization of a 10 GHz 0.8 ps mode-locked Er-fiber soliton laser with asynchronous phase modulation is demonstrated by controlling the cavity length to lock the deviation frequency at 25 kHz. (C) 2005 Optical Society of America.
Stabilizing the relative carrier-envelop phase of hybridly synchronized ultrafast Yb and Er fiber laser systems by the feed-forward scheme
(2015)
Hsiang, Wei-Wei
;
Fong, Bo-Jyun
;
Lin, Wei-Ting
;
Wu, Shang-Ying
;
Peng, Jin-Long
Stabilization of the relative carrier-envelope (CE) phase for hybridly synchronized two-color fs Yb and Er fiber laser systems is demonstrated for the first time by utilizing the feed-forward scheme based on an acousto-optic frequency shifter.
Subfemtosecond hybrid synchronization between ultrafast Yb and Er fiber laser systems by controlling the relative injection timing
(2013-09-01)
Tsai, Bo-Wei
;
Wu, Shang-Ying
;
Hu, Chieh
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Hsiang, Wei-Wei
;
Lai, Yinchieh
We report experimental as well as theoretical investigation of the key factors that influence the relative timing jitter between hybrid synchronized ultrafast Yb and Er fiber laser systems. Experimental results show that, within the achievable synchronization range, the synchronization performance varies significantly with the relative injection timing between the 1 mu m master and 1.5 mu m slave pulses. This observation is in agreement with the insights obtained from the theoretical analysis, which identifies the retiming effect as a function of the initial condition of the master-slave pulse collision. By controlling the relative injection timing with a low-bandwidth intracavity feedback, relative timing jitter as low as 0.87 fs (within 1.9 MHz bandwidth) is successfully obtained. (C) 2013 Optical Society of America
Subfemtosecond Synchronization between Yb-fiber and Er-fiber Lasers by Controlling the Relative Injection Timing
(2013-01-01)
Hsiang, Wei-Wei
;
Tsai, Bo-Wei
;
Hu, Chieh
;
Wu, Shang-Ying
;
Lai, Yinchieh
The relative timing between the injection and slave pulses is found to be the key factor to achieve sub-fs timing jitter (0.87 fs, 1.9 MHz bandwidth) between Yb-fiber and Er-fiber fs lasers with hybrid synchronization.
Synchronous-asynchronous laser mode-locking transition
(2015-07-27)
Wu, Shang-Ying
;
Hsiang, Wei-Wei
;
Lai, Yinchieh
;
光電工程學系
;
光電工程研究所
Synchronous-asynchronous mode-locking transition in a hybrid active and passive mode-locked laser is investigated theoretically. Three distinct mode-locking states are found and their transition diagram under varying detuning frequency and modulation strength is determined. By examining the steady-state lasing gain as a function of the detuning modulation frequency, we also clarify why the laser will become unstable near the transition points and why the nonlinear saturable absorption effect is crucial for the stable asynchronous mode-locking operation.