Browsing by Author "Huang, J. Y."

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> 100-kW linearly polarized pulse fiber amplifier seeded by a compact efficient passively Q-switched Nd:YVO4 Laser
(2012-11-01)
Zhuang, W. Z.
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Huang, W. C.
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Cho, C. Y.
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Huang, Y. P.
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Huang, J. Y.
We thoroughly develop compact high-peak-power Nd:YVO4/Cr4+:YAG passively Q-switched lasers (PQS) as the seed source of the fiber amplifier. We exploit a nearly hemispherical cavity to reach the second threshold criterion and systematically consider the thermal lensing effect and the mode-size matching in the overall optimization. Employing a Cr4+:YAG absorber with 70% initial transmission, we obtain a 50-kHz seed pulse train with the pulse duration of 4.8 ns and the pulse energy of 22 mu J at a pump power of 5.4 W. Injecting this seed laser into a polarization maintained Yb-doped fiber, the pulse energy and peak power at a pump power of 16 W are enhanced up to 178 mu J and 37 kW, respectively. We also use an absorber with 40% initial transmission to generate a 25 kHz pulse train with the pulse duration of 1.6 ns and the pulse energy of 36 mu J at a pump power of 5.4 W. With this seed laser, we find that the surface damage of the fiber limits the maximum pulse energy and peak power to be 192 mu J and 120 kW, respectively.
A note on Group Selection with multiple quality characteristics: power comparison of two methods
(2019-03-04)
Pearn, W. L.
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Lin, Chen-ju
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Chen, Y. H.
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Huang, J. Y.
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工業工程與管理學系
The Group Selection problem is an essential problem in the supplier selection process. The objective of the problem is to select a subset of suppliers containing the best among multiple candidate suppliers. Manufacturers should procure parts from the selected suppliers to produce high-quality products. Lin, C.J., W.L. Pearn, J.Y. Huang, and Y.H. Chen [2017. "Group Selection for Processes with Multiple Quality Characteristics." Communications in Statistics - Theory and Methods. doi:] considered the problem under multiple quality characteristics, and proposed the Modified Bonferroni method and the Multiple Comparisons with the Best (MCB) method to tackle the problem. The two methods, however, may select different subset containing the best depending on the magnitude of the differences among the k estimated index values. In this paper, we derive the power function for the Modified Bonferroni method, and compare the power of the two methods with extensive simulations. The results show that the MCB method is more powerful than the Modified Bonferroni method when the actual number of the best process is one. On the other hand, the Modified Bonferroni method significantly outperforms the MCB method when the actual number of the best process is greater than one. The results provide practitioners with useful reference about the properties of the two methods for supplier selection.
ab initio calculated frequency-dependent nonlinear optical properties on CsGeBr3
(2006-01-01)
Tang, L. C.
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Chang, Y. C.
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Huang, J. Y.
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Chang, C. S.
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光電工程學系
A systematic first-principles calculation of the linear and second-order optical susceptibilities as functions of frequency for CsGeBr3 is presented. Specifically, we study the relation between the structural properties and the optical responses. Three structural deformation factors, Delta alpha, d(Ge), d(X) are used to express the degree of distortion from the ideal perovskite structure in bond angle, Ge position, and anion position, respectively. Based on our first-Principles studies, we find that Delta alpha and d(Ge) increase, while d(X) decreases as we substitute the halo-en ion from Cl to Br and then to I. The dielectric function and the second harmonic generation coefficient are also found to increase with increasing Delta alpha and d(Ge). Our calculation indicates that the direct bandgap, E-g, of CsGeX3 occurs at the R-point for all three compounds, and its magnitude decreases as Delta alpha and d(Ge) increase (i.e. E-g(CsGeI3) < E-g(CsGeBr3) < E-g(CsGeCl3)). Our partial density of states (PDOS) analysis reveals that the valence band maximun (VBM) and conduction band minimum (CBM) are mainly associated with the p-orbitals of Germanium. Interband and intraband analysed results for chi((2))(ijk) in CsGeBr3 can be separated into two main groups of peaks. One was contributed from the magnitude electronic bandgap; the other part was recognized to be attribution from the distortional structural factors. The magnitudes Of chi((2))(ijk) were in the same manner with some reported experiment near the band gap.
Analytical model for optimizing the parameters of an external passive Q-switch in a fiber laser
(2008-05-01)
Huang, J. Y.
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Liang, H. C.
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Su, K. W.
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Chen, Y. F.
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電子物理學系
An analytical model is developed for optimizing two key parameters of an external passive Q-switch in a fiber laser from the criterion of the minimum average mode area inside the saturable absorber. One parameter is the optimum focal position that is analytically derived to be a function of the thickness and initial transmission of the saturable absorber. The other parameter is the optimum magnification of the reimaging optics that is analytically derived to be in terms of the numerical aperture and core radius of the laser fiber as well as the thickness and initial transmission of the saturable absorber. To demonstrate the utilization of the present model, an experiment on the subject of the passively Q-switched fiber laser is performed and optimized. (C) 2008 Optical Society of America.
Analytical model for the design of external-cavity passively Q-switched fiber lasers
(2008)
Huang, J. Y.
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Liang, H. C.
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Su, K. W.
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Chen, Y. F.
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電子物理學系
An analytical model has been developed to minimize the effective mode area in a saturable absorber for an external-cavity passively Q-switched fiber laser. Under the condition of minimum effective mode size inside the saturable absorber, the analytical expressions for two key parameters of an optimum system have been derived. One parameter is the optimum focal position that is analytically derived to be a function of the thickness and initial transmission of the saturable absorber. The other parameter is the optimum magnification of the re-imaging optics that is analytically derived to be in terms of the numerical aperture and core radius of the laser fiber as well as the thickness and initial transmission of the saturable absorber. The present model provides a straightforward procedure to adopt a focusing system for the output performance. A diode-pumped ytterbium-doped fiber lasers with a Cr:YAG crystal as a saturable absorber is considered to illustrate the utility of the present model.
Blue-light generating femtosecond wavelength-tunable non-collinear optical parametric amplifier
(2006-03-02)
Pan, Ci-Ling
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Huang, J. Y.
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Zhang, Jing-Yuan
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Lee, Chao-Kuei
The present invention discloses a means of the generation of tunable femtosecond pulses from 380 nm to 465 nm near the degenerate point of a 405-nm pumped type-I BBO non-collinearly phase-matched optical parametric amplifier (NOPA). The tunable UV/blue radiation is obtained from sum frequency generation (SFG) between the OPA output and the residual fundamental beam at 810-nm and cascaded second harmonic generation (SHG) of OPA. With a pumping energy of 75 mJ at 405 nm, the optical conversion efficiency from the pump to the tunable SFG is more than 5% and the efficiency of SHG of the OPA is about 2%.
Comparative studies for Cr(4+):YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers
(2009-11-09)
Huang, J. Y.
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Zhuang, W. Z.
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Huang, W. C.
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Su, K. W.
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Hu, C.
We demonstrate comparative studies for Cr(4+):YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr(4+):YAG crystal, respectively. The maximum pulse energies obtained with the Cr(4+):YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively. (C) 2009 Optical Society of America
Comparative studies for Cr4+:YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers
(2009-11-09)
Huang, J. Y.
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Zhuang, W. Z.
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Huang, W. C.
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Su, K. W.
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Hu, C.
We demonstrate comparative studies for Cr4+:YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr4+:YAG crystal, respectively. The maximum pulse energies obtained with the Cr4+:YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively. (C) 2009 Optical Society of America
DEVICE MODELING OF A MICROMORPH TANDEM SOLAR CELL USING AMPS-1D
(2010)
Huang, J. Y.
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Hsu, C. W.
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Shieh, Jia-Min
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Yu, Peichen
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光電工程學系
This work first theoretically optimize the amorphous (a-Si:H) and the microcrystalline (mu c-Si:H) devices characteristics, and then perform studies for micromorph tandem solar cells. The studies calculated by AMPS-1D show that the TCO work function has obvious influence on the open-circuit voltage. Moreover, the power conversion efficiency of an a-Si:H cell is optimized by changing the absorber's layer thickness and mobility gap. Furthermore, a critical doping concentration of mu c-Si:H films limiting the barrier height of a grain boundary (GB) is observed. After optimizing sub cell mutually, we combine the individual junctions to construct a micromorph cell which has an efficiency of 9.24%.
Group selection for processes with multiple quality characteristics
(2018-01-01)
Lin, Chen-ju
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Pearn, W. L.
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Huang, J. Y.
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Chen, Y. H.
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工業工程與管理學系
Evaluating and comparing process capabilities are important tasks of production management. Manufacturers should apply the process with the highest capability among competing processes. A process group selection method is developed to solve the process selection problem based on overall yields. The goal is to select the processes with the highest overall yield among I processes under multiple quality characteristics, I > 2. The proposed method uses Bonferroni adjustment to control the overall error rate of comparing multiple processes. The critical values and the required sample sizes for designated powers are provided for practical use.
High power passively Q-switched ytterbium fiber laser with Cr4+: YAG as a saturable absorber
(2007-01-22)
Huang, J. Y.
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Liang, H. C.
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Su, K. W.
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Chen, Y. F.
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電子物理學系
We report an efficient high-peak-power and high-average-power passively Q-switched ytterbium fiber laser with a Cr4+: YAG crystal as a saturable absorber in an external-resonator configuration. At an incident pump power of 17.5 W, the passively Q-switched fiber laser produces an average power greater than 6.2 W with a pulse repetition rate of 48 kHz. The output pulses noticeably display a mode-locking phenomenon that leads to the maximum peak power to be higher than 20 kW. (c) 2007 Optical Society of America.
High-peak-power flashlamp-pumped passively Q-switched Nd : YAG laser with AlGaInAs quantum wells as a saturable absorbers - art. no. 68712M
(2008)
Liang, H. C.
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Huang, J. Y.
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Huang, S. C.
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Su, K. W.
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Chen, Y. F.
We demonstrate an AlGaInAs saturable absorber with a periodic quantum wells (QWs)/barrier structure that can be used to achieve an efficient high-peak-power and high-pulse-energy passively flashlamp-pumped Q-switched Nd:YAG laser at 1.06 um. The barrier layers are designed to locate the QW groups in the region of the nodes of the lasing standing wave to avoid damage. With an incident pump voltage of 14.5 J, a single pulse was generated with a pulse energy of 14 mJ and a Q-switched pulse width of 13 ns. The maximum peak power was greater than 1.08 MW.
High-power picoseconds 355 nm laser by third harmonic generation based on CsB3O5 crystal
(2007-07-01)
Guo, L.
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Wang, G. L.
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Zhang, H. B.
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Cui, D. F.
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Wu, Y. C.
We report on the high average power third harmonic generation (THG) of a mode-locked picosecond laser in a CsB3O5 (CBO) crystal. The picosecond laser beam at 1064 nm is produced by a home-made 30 W master oscillator power-amplifier (MOPA) Nd:YVO4 laser system. The maximum THG output at 355 nm is up to 5.4 W. We also investigate the phase matching angle at different temperatures. During high power operation, the temperature of the CBO crystal is set at a high temperature of more than 100 degrees C. The THG system has shown a fine long-term stability for more than two months of operation.
High-pulse-energy, passively Q-switched Yb-doped fiber laser with AlGaInAs quantum wells as a saturable absorber
(2009-08-01)
Huang, J. Y.
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Huang, W. C.
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Zhuang, W. Z.
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Su, K. W.
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Chen, Y. F.
We demonstrate an efficient, high-pulse-energy, passively Q-switched Yb-doped fiber laser with AlGaInAs quantum wells (QWs) as a saturable absorber. The AlGaInAs QW material is designed to provide a large modulation change and a quite-low nonsaturable loss. At an incident pump power of 7.6 W, an average output power of 3.8 W, pulse energy of 300 mu J, pulse repetition rate of 12.5 kHz, and pulse duration of 30 ns was obtained. (C) 2009 Optical Society of America
Hybrid Q-switched Yb-doped fiber laser
(2011-05-09)
Huang, J. Y.
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Zhuang, W. Z.
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Huang, W. C.
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Su, K. W.
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Huang, K. F.
We investigate the performance of a hybrid Q-switched (HQS) fiber laser that is constructed with a low RF-power driven acousto-optic (AO) Q-switch and an AlGaInAs semiconductor saturable absorber. Compared to a pure passively Q-switched (PQS) fiber laser, the ratio of timing jitter to pulse period can be significantly reduced from 2% to 0.3% in the regime of far above threshold. On the other hand, the prelasing effect in a pure actively Q-switched fiber laser can be considerably improved. More importantly, the maximum pulse energy of the HQS fiber laser can be increased approximately 25% in comparison with the result of the PQS fiber laser. At a pump power of 24 W, the highest pulse energy is up to 0.56 mJ with the pulse duration of 50 ns at the repetition rate of 23 kHz. (C) 2011 Optical Society of America
Improvement of stability and efficiency in diode-pumped passively Q-switched intracavity optical parametric oscillator with a monolithic cavity
(2012)
Huang, J. Y.
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Zhuang, W. Z.
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Huang, Y. P.
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Huang, Y. J.
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Su, K. W.
We improve the performance of intracavity optical parametric oscillator (IOPO) pumped by a diode-pumped Q-switched Nd:YVO4/Cr4+:YAG laser. The IOPO cavity is formed independently by a monolithic KTP crystal that the mirrors are directly deposited on top of the nonlinear crystal. We study the performances of this IOPO cavity with different reflectivity of the output coupler at 1.5 mu m (R-s) of 80 and 50%. The average power of 1.5 mu m is up to 3.3 W at the maximum pump power of 16.8Wfor both cases. The diode-to-signal conversion efficiency is up to 20%, which is the highest one for IOPOs to our best knowledge. At the maximum pump power, the pulse energies are 41 mu J with the pulse width of 3 ns at a pulse repetition rate (PRR) of 80 kHz for R-s = 80% and 51 mu J with the pulse width of 1.2 ns at a PRR of 65 kHz for R-s = 50%, respectively. The pulse amplitude fluctuations in standard deviation are 2.6% for R-s = 80% and 4% for R-s = 50%, respectively. [GRAPHICS] (C) 2012 by Astro, Ltd.
InGaAs quantum-well saturable absorbers for a diode-pumped passively Q-switched Nd : YAG laser at 1123 nm
(2007-01-10)
Huang, J. Y.
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Liang, H. C.
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Su, K. W.
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Lai, H. C.
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Chen, Y. -F.
A low-loss semiconductor saturable absorber based on InGaAs quantum wells was developed for highly efficient Q switching of a diode-pumped Nd:YAG laser operating at 1123 nm. With an incident pump power of 16 W, an average output power of 3.1 W with a Q-switched pulse width of 77 ns at a pulse repetition rate of 100 kHz was obtained. (c) 2007 Optical Society of America.
Investigation of the electronic, linear and second-order nonlinear optical properties for the wide bandgap chalcopyrite ternary nitrides
(2008)
Tang, L. C.
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Chang, Y. C.
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Huang, J. Y.
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Chang, C. S.
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光電工程學系
We present the results of the ab initio calculated electronic properties, first and second harmonic generation for the A(II)B(IV) N(2), (A(II)=Be, B(IV)=C, Si, Ge) compounds with chalcopyrite structure performed using the Linear Augmented Slater-Type Orbitals (LASTO) method. The second-order optical susceptibilities as functions of frequency for A(II)B(IV)N(2) are also presented. Specifically, we study the relation between the structural properties and the optical responses. Our electronic band structure and density of states (PDOS) analysis reveal that the underestirnate bandgaps of these chalcopyrite A(II)B(IV)N(2) are wide enough (from 4eV to 6eV), direct transition and mainly located at F-point. Calcultion results show this new category wide-bandgap ternary nitrides has potential applications in optoelectronics.
Passive Q switching of Er-Yb fiber laser with semiconductor saturable absorber
(2008-03-03)
Huang, J. Y.
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Huang, S. C.
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Chang, H. L.
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Su, K. W.
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Chen, Y. F.
A high-performance A1GaInAs quantum-well saturable absorber is developed for passively Q-switched Er-Yb double-clad fiber lasers at 1560 nm. With an incident pump power of 13.5 W, an average output power of 1.26 W with a pulse repetition rate of 12 kHz is obtained. The maximum peak power is greater than 500 W. (C) 2008 Optical Society of America.
Passively Q-switched Yb3+: YCa4O(BO3)(3) laser with InGaAs quantum wells as saturable absorbers
(2007-04-20)
Liang, H. C.
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Huang, J. Y.
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Su, K. W.
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Lai, H. C.
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Chen, Y. F.
A diode-pumped Yb:YCOB laser at 1086 nm is passively Q switched by using InGaAs quantum wells as saturable absorbers and utilizing the Bragg mirror structure as an output coupler. With an absorbed pump power of 9.2 W the laser produces pulses of 100 ms duration with average pulse energy of as much as 165 mu J at a pulse repetition rate of 7 kHz. (c) 2007 Optical Society of America.