Browsing by Author "Huang, W. C."

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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.
BCB-to-oxide bonding technology for 3D integration
(2012-02-01)
Lin, S. L.
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Huang, W. C.
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Ko, C. T.
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Chen, K. N.
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電子工程學系及電子研究所
Process optimization of BCB polymer to silicon oxide bonding was investigated. The suitable bonding temperature is about 300 degrees C, while bond failure of BCB-to-oxide bonding is observed starting from 400 degrees C. Bonding interface morphologies and bond strengths of BCB-to-oxide bonding were investigated as well. PECVD oxide to BCB bonding has better bonding quality than that of thermal oxide to BCB bonding. Si-O-Si bonds may be the reason of a strong BCB to oxide bonding. Water molecules link BCB and oxide surfaces during the initial contact, while Si-O-Si bonds are formed during bonding. This proposed mechanism of BCB-to-oxide bonding provides a guideline for polymer to oxide hybrid bonding technology in 3D integration. (C) 2011 Elsevier Ltd. All rights reserved.
Bonding Temperature Optimization and Property Evolution of SU-8 Material in Metal/Adhesive Hybrid Wafer Bonding
(2011-08-01)
Chen, K. N.
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Cheng, C. A.
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Huang, W. C.
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Ko, C. T.
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電子工程學系及電子研究所
Bonding temperature optimization of SU-8 material for metal/adhesive hybrid bonding was investigated. The good bond quality of SU-8 adhesive can be achieved with the bonding temperature between 150 degrees C and 250 degrees C, while bond failures of SU-8 wafers are observed starting from 275 degrees C. IR transmittance spectra measurements indicate the crosslinks inside SU-8 break and further bond failure is observed due to the large decomposition of epoxy rings and phenyl in plane bending above 275 degrees C. This research provides guidelines of material selection and bonding parameters for heterogeneous integration, 3DIC and MEMS applications using metal/adhesive hybrid bonding.
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
Growth Parameters Optimization of GaN High Electron Mobility Transistor Structure on Silicon Carbide Substrate
(2014-01-01)
Wong, Y. Y.
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Huang, S. C.
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Huang, W. C.
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Lumbantoruan, F.
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Chiu, Y. S.
High electron mobility transistors heterostructures of AlGaN/GaN were grown by metalorganic chemical vapor deposition system on silicon carbide substrate. The growth parameters such as AlN buffer thickness, AlN spacer growth time and Al content in AlGaN barrier layer were optimized. Moreover, the effects of chamber pressure and V/III ratio at the initial growth state of GaN on film crystal quality were also investigated. The optimized AlGaN/GaN heterostructure has AlN buffer thickness of 120 nm, AlN spacer growth time of 10 s and Al content of 28% in the barrier layer. Furthermore, as a result of using higher chamber pressure and lower V/III, both the GaN crystal quality and electron mobility in the AlGaN/GaN were also significantly improved. After the growth parameter optimization, the GaN (002) and (102) planes exhibited X-ray rocking curve widths of 209 arcsec and 273 arcsec, respectively. Besides, the AlGaN/GaN structure also has an electron mobility of 1832 cm(2)/V-s and a sheet electron density of 1.08 10(13) cm(-2), which yielding a sheet resistance of 316 Omega/sq.
High-power, diode-end-pumped, multigigahertz self-mode-locked Nd:YVO(4) laser at 1342 nm
(2010-01-01)
Liang, H. C.
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Huang, Y. J.
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Huang, W. C.
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Su, K. W.
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Chen, Y. F.
We report on a high-power, diode-pumped, self-mode-locked laser at 1342 nm with the Kerr effect arising from large third-order nonlinearity of Nd:YVO(4) crystal. At the pump power of 10.2 W, the average output power of 1.2 W was generated with a repetition rate in the range of 2-6 GHz. The mode-locked pulse width can be smoothly varied from 11.5 to 37 ps by controlling the amount of spatial hole burning. (C) 2009 Optical Society of America
High-power, diode-end-pumped, multigigahertz self-mode-locked Nd:YVO4 laser at 1342 nm
(2010-01-01)
Liang, H. C.
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Huang, Y. J.
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Huang, W. C.
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Su, K. W.
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Chen, Y. F.
We report on a high-power, diode-pumped, self-mode-locked laser at 1342 nm with the Kerr effect arising from large third-order nonlinearity of Nd:YVO4 crystal. At the pump power of 10.2 W, the average output power of 1.2 W was generated with a repetition rate in the range of 2-6 GHz. The mode-locked pulse width can be smoothly varied from 11.5 to 37 ps by controlling the amount of spatial hole burning. (C) 2009 Optical Society of America
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
Millijoule-level Yb-doped photonic crystal fiber laser passively Q-switched with AlGaInAs quantum wells
(2010-12-20)
Zhuang, W. Z.
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Huang, W. C.
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Chiang, P. Y.
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Su, K. W.
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Huang, K. F.
We report on a millijoule-level Yb-doped photonic crystal fiber (PCF) laser passively Q-switched with AlGaInAs quantum wells (QWs). Three types of AlGaInAs devices with different QW numbers are fabricated to investigate the performance. With 50 groups of three AlGaInAs QWs as a saturable absorber (SA), the PCF laser generates an average power of 7.1 W with a pulse repetition rate of 6.5 kHz at a pump power of 16 W, corresponding to the pulse energy of 1.1 mJ. The maximum peak power is up to 110 kW. (C) 2010 Optical Society of America
Nonpolar a-plane GaN grown on r-plane sapphire using multilayer AlN buffer by metalorganic chemical vapor deposition
(2011-01-15)
Chiang, C. H.
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Chen, K. M.
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Wu, Y. H.
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Yeh, Y. S.
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Lee, W. I.
Mirror-like and pit-free non-polar a-plane (11-20) GaN films are grown on r-plane (1-102) sapphire substrates using metalorganic chemical vapor deposition (MOCVD) with multilayer high-low-high temperature AlN buffer layers. The buffer layer structure and film quality are essential to the growth of a flat, crack-free and pit-free a-plane GaN film. The multilayer AlN buffer structure includes a thin low-temperature- deposited AlN (LT-AlN) layer inserted into the high-temperature-deposited AlN (HT-AlN) layer. The results demonstrate that the multilayer AlN buffer structure can improve the surface morphology of the upper a-plane GaN film. The grown multilayer AlN buffer structure reduced the tensile stress on the AlN buffer layers and increased the compressive stress on the a-plane GaN film. The multilayer AlN buffer structure markedly improves the surface morphology of the a-plane GaN film, as revealed by scanning electron microscopy. The effects of various growth V/III ratios was investigated to obtain a-plane GaN films with better surface morphology. The mean roughness of the surface was 1.02 nm, as revealed by atomic force microscopy. Accordingly, the multilayer AlN buffer structure improves the surface morphology and facilitates the complete coalescence of the a-plane GaN layer. (C) 2010 Elsevier B.V. All rights reserved.
Passively Q-switched photonic crystal fiber laser and intracavity optical parametric oscillator
(2010-04-26)
Zhuang, W. Z.
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Huang, W. C.
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Huang, Y. P.
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Su, K. W.
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Chen, Y. F.
We report on a passively Q-switched photonic crystal fiber (PCF) laser with Cr(4+): YAG as a saturable absorber. Under a pump power of 14.2 W, the maximum pulse energy is up to 630 mu J with a pulse width of 36 ns at a repetition rate of 5.6 kHz. With an intracavity optical parametric oscillator, the passively Q-switched PCF laser is used to generate the signal wave at 1515 nm. The output pulse energy of the signal wave is found to be 140 mu J with a pulse width as short as 1.0 ns at a repetition rate of 3.3 kHz. The very short pulse width leads to the peak power up to 140 kW. (C) 2010 Optical Society of America
Photoluminescence and Raman studies of GaN films grown by MOCVD
(2009)
Luong Tien Tung
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Lin, K. L.
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Chang, E. Y.
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Huang, W. C.
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Hsiao, Y. L.
The photoluminescence (PL) of high quality GaN epitaxial layer grown by MOCVD was investigated for various excitation power and temperatures from 8.3 to 300K. The PL at 8.3 K and with relatively low excitation power of GaN film grown on c-plane sapphire by using MOCVD shows clearly free-exciton A, B and exciton A bound to neutral donors (D degrees X) at 3.502 eV, 3.509 eV, and 3.496 eV, respectively. The full width at half maximum (FWHM) and binding energy of exciton A of the high quality GaN film were evaluated as small as 3.7 meV and 27.9 +/- 0.5 meV, respectively. In addition, PL and Raman scattering of GaN films grown on r-plane sapphire and (111) Si substrates by using MOCVD were examined. The residual stress effect was detected in all films.
Self-mode-locked Nd:GdVO(4) laser with multi-GHz oscillations: manifestation of third-order nonlinearity
(2009-10-01)
Liang, H. C.
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Chang, H. L.
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Huang, W. C.
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Su, K. W.
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Chen, Y. F.
The large third-order nonlinearity of GdVO(4) crystals is employed to realize the compact efficient continuous-wave self-mode locking in the range of several GHz in a Nd:GdVO(4) laser with a simple linear cavity without the need of any additional components. With a pump power of 2.5 W, the compact laser cavity produces average output powers greater than 0.7 W with a pulse width as short as 23 ps in the range of 2-6 GHz.
Self-mode-locked Nd:GdVO4 laser with multi-GHz oscillations: manifestation of third-order nonlinearity
(2009-10-01)
Liang, H. C.
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Chang, H. L.
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Huang, W. C.
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Su, K. W.
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Chen, Y. F.
The large third-order nonlinearity of GdVO4 crystals is employed to realize the compact efficient continuous-wave self-mode locking in the range of several GHz in a Nd:GdVO4 laser with a simple linear cavity without the need of any additional components. With a pump power of 2.5 W, the compact laser cavity produces average output powers greater than 0.7 W with a pulse width as short as 23 ps in the range of 2-6 GHz.
Widely tunable eye-safe laser by a passively Q-switched photonic crystal fiber laser and an external-cavity optical parametric oscillator
(2011-09-01)
Chang, H. L.
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Zhuang, W. Z.
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Huang, W. C.
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Huang, J. Y.
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Huang, K. F.
We report on a widely tunable passively Q-switched photonic crystal fiber (PCF) laser with wavelength tuning range up to 80 nm. The PCF laser utilizes an AlGaInAs quantum well/barrier structure as a saturable absorber and incorporates an external-cavity optical parametric oscillator (OPO) to achieve wavelength conversion. Under a pump power of 13.1 W at 976 nm, the PCF laser generated 1029-nm radiation with maximum output energy of 750 mu J and was incident into an external-cavity OPO. The output energy and peak power of signal wave was found to be 138 mu J and 19 kW, respectively. By tuning the temperature of nonlinear crystal, periodically poled lithium niobate (PPLN), in the OPO, the signal wavelength in eye-safe regime from 1513 to 1593 nm was obtained. (C) 2011 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA