Browsing by Author "Lin, SH"

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A hetero-associative memory using phase-multiplexing references
(2000-04-01)
Hsieh, ML
;
Hsu, KY
;
Lin, SH
;
電子物理學系
;
光電工程學系
We present a hetero-associative memory for multiple-associative pairs by using the phase-multiplexing technique. Two methods for reducing the cross-talk between different association pairs are proposed. An optical experiment for the edge-enhancement associative memory is also demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.
A Lagrangean relaxation-based approach for routing and wavelength assignment in multigranularity optical WDM networks
(2004-11-01)
Lee, SSW
;
Yuang, MC
;
Tien, PL
;
Lin, SH
;
資訊工程學系
Optical wavelength-division multiplexed (WDM) networks often include optical cross-connects with multigranularity switching capability such as switching on a single lambda, a waveband, or an entire fiber basis. In addition, it has been shown that routing and wavelength assignment (RWA) in an arbitrary mesh WDM network is an NP-complete problem. In this paper, we propose an efficient approximation approach, called Lagrangean relaxation with heuristics (LRH), aimed to resolve RWA in multigranularity WDM networks particularly with lambda and fiber switches. The task is first formulated as a combinatorial optimization problem in which the bottleneck link utilization is to be minimized. The LRH approach performs constraint relaxation and derives a lower-bound solution index according to a set of Lagrangean multipliers generated through subgradient-based iterations. In parallel, using the generated Lagrangean multipliers, the LRH approach employs a new heuristic algorithm to arrive at a near-optimal upper-bound solution. With lower and upper bounds, we conduct a performance study on LRH with respect to accuracy and convergence speed under different parameter settings. We further draw comparisons between LRH and an existing practical approach via experiments over randomly generated and several well-known large sized networks. Numerical results demonstrate that LRH outperforms the existing approach in both accuracy and computational time complexity, particularly for larger sized networks.
A novel and direct determination of the interface traps in sub-100nm CMOS devices with direct tunneling regime (12 similar to 16A) gate oxide
(2002)
Chung, SS
;
Chen, SJ
;
Yang, CK
;
Cheng, SM
;
Lin, SH
For the first time, an improved charge pumping (CP) method has been implemented for direct determination of the interface traps in ultra-short gate length CMOS devices with ultra-thin gate oxide in the direct tunneling regime. The leakage current in a 12-16A gate oxide can be removed from the measured CP current, which enables accurate determination of the interface traps. This method has, been demonstrated successfully for various RTNO grown and RPN treated oxide CMOS devices with very thin gate oxide. Moreover, it can be used as a good monitor of ultra-thin gate oxide process and the evaluations of device reliabilities in relating to the interface trap generation.
A novel approach of fabricating germanium nanocrystals for nonvolatile memory application
(2004-01-01)
Chang, TC
;
Yan, ST
;
Liu, PT
;
Chen, CW
;
Lin, SH
A nonvolatile memory device embedded with Ge nanocrystal dots is fabricated by the thermal oxidation of Si0.8Ge0.2 combined with a rapid thermal annealing at 950degreesC in N-2 gas. The tunnel oxide in the nonvolatile memory is controlled to be 4.5 nm thick and embedded with 5.5 nm Ge nanocrystals. A low operating voltage, 5 V, is implemented and a significant threshold-voltage shift, 0.42 V, is observed. When the electrons are trapped in the Ge nanocrystals, the effect of Coulomb blockade prevents the injection and storage of more electrons and decreases the leakage current. Also, the retention characteristics are tested to be robust. (C) 2003 The Electrochemical Society.
Analyses on physical mechanism of holographic recording in phenanthrenequinone-doped poly(methyl methacrylate) hybrid materials
(2004-09-01)
Hsiao, YN
;
Whang, WT
;
Lin, SH
;
材料科學與工程學系
;
電子物理學系
The photoproducts in phenanthrenequinone (PQ)-dissolved methyl methacrylate (MMA) liquid samples and PQ-doped poly(methyl methacrylate) (PQ/PMMA) solid photopolymer samples have been analyzed by various chemical measurements. A mechanism for holographic recording in our PQ/PMMA photopolymer is proposed. By UV-VIS transmission and photoluminescence spectral measurements, we find that under light exposure the molecular structure of PQ is transformed to be less conjugated. The measured results of mass spectra, Fourier transform infrared spectra, NMR spectra, and gel permeation chromatograph of analyses provide some evidence for recognizing the molecular structure of the photoproducts in our PQ/PMMA photopolymers. The results show that under light exposure the PQ and MMA form new molecules, mainly an adduct of one PQ molecule with one MMA molecule. In addition, PQ also reacts as a photoinitiator to form PMMA oligomers in our samples. The structure change of the PQ molecule induces a strong change of the refractive index in the material. It provides a mechanism to record a phase hologram in our PQ/PMMA photopolymer. Holographic recordings in the samples are demonstrated, and the dynamic range of the sample is investigated. (C) 2004 Society of Photo-Optical Instrumentation Engineers.
Analysis of grating detuning on volume holographic data storage
(2000)
Lin, SH
;
Hsu, KY
;
電機學院
;
College of Electrical and Computer Engineering
Scalar diffraction theory has been utilized to analyze grating detuning effect in a volume holographic data storage system. The general formulas for describing the two-dimensional distribution of the retrieval image under the detuning effect have been derived. Computer simulations show that the smaller writing angle provides better performance for a holographic storage system in terms of the uniformity and the pixel shift of the retrieval image.
Anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals with extended wavelength range
(2002-02-25)
Zaitsev, AK
;
Hsu, KY
;
Lin, SH
;
交大名義發表
;
National Chiao Tung University
The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mismatch of Bragg condition. The wavelength range may extent in several times the range of ordinary isotropic diffraction on the grating of the same spacing and thickness. Theoretical explanation of this phenomena and experimental results of widerange diffraction in BaTiO3 photorefractive crystal are also presented. (C) 2002 Optical Society of America.
Comparison of the recording dynamics of phenanthrenequinone-doped poly(methyl methacrplate) materials
(2001-07-01)
Mumbru, J
;
Solomatine, I
;
Psaltis, D
;
Lin, SH
;
Hsu, KY
A comparative analysis of phenanthrenequinone-doped poly(methyl methacrylate) materials fabricated at California Institute of Technology and National Chiao Tung University is performed in order to understand the differences exhibited in their recording and baking dynamics. (C) 2001 Published by Elsevier Science B.V.
Contradirectional two-wave mixing with partially coherent waves in photorefractive crystals
(1996-08-01)
Yi, XM
;
Lin, SH
;
Yeh, PC
;
Hsu, KY
;
光電工程學系
We investigate contradirectional two-wave mixing with partially coherent waves in photorefractive crystals in the nondepleted pump regime. Equations governing the propagation of the self-coherence function and the mutual-coherence function of the signal wave and the pump wave are derived and simulated numerically. Numerical solutions of these equations are in excellent agreement with the experimental measurements. (C) 1996 Optical Society of America
Creation of weighted volume grating by holographic method
(2001)
Zaitsev, AK
;
Lin, SH
;
Hsu, KY
;
交大名義發表
;
National Chiao Tung University
The creation method of a weighted holographic grating in photopolymer film is discussed, It is based on interference of two beams passed through weighting masks. Due to weighing the grating's response has sidelobe level to be reduced.
Dissociation and dynamics of the high-vibrational-state HF molecules under intense half-cycle and few-cycle pulses
(2000-03-01)
Lin, JT
;
Lin, SH
;
Jiang, TF
;
物理研究所
;
Institute of Physics
This work explores the dissociation dynamics and angular distribution of the HF molecule interacting with intense half-cycle and few-cycle pulses, including the rotational degree of freedom. The dependences of the dissociation probability on both the pulse type and the pulse duration are discussed. Our results indicate that the angular distribution of the dissociation probability is highly asymmetric to the perpendicular direction of field polarization, and becomes more symmetric with an increase in the number of field cycles. The spatial distribution of the wave function demonstrates the feasibility of constructing a molecular wave packer by interacting with the half-cycle pulse.
Doped PMMA photopolymer for volume holographic recording
(2003)
Lin, SH
;
電子物理學系
;
Department of Electrophysics
In this paper, we report investigations on chemical analyses and optical measurements of our PQ doped PMMA photopolymer material. We have analyzed chemical compositions of four different samples: PQ doped PMMA solid and PQ dissolved MMA liquid samples, with light exposed and unexposed conditions, respectively. The investigations provide us a good understanding about the photochemical behaviors of the PQ and the MMA molecules during optical recording. Then, a mechanism for holographic recording is proposed. This result has been applied to develop photopolymers doped with different dye molecules. With changing of dye molecules, we have made three new PMMA-based photopolymers. Their holographic recording characteristics have been tested and discussed.
Effect of grating detuning on holographic data storage
(2000)
Lin, SH
;
Hsu, KY
;
電子物理學系
;
Department of Electrophysics
We use the scaler diffraction theory to analyze the grating detuning effect in a volume holographic data storage system. The general formulas for describing the two-dimensional distribution of retrieved image under the detuning effect have been derived. In terms of the image uniformity and the pixel shift of the retrieval image, computer simulations are used to perform a quantitative analysis.
Effect of ruthenium doping on the optical and photorefractive properties of Bi12TiO20 single crystals
(2002-03-15)
Marinova, V
;
Hsieh, ML
;
Lin, SH
;
Hsu, KY
;
電子物理學系
Bi12TiO20 (BTO) single crystals nominally pure and doped with ruthenium are grown by top-seeded solution growth method. The effect of ruthenium concentration on optical and photorefractive properties is studied. Strong influence of doping on these properties is observed. It is shown that optical transmission of crystal samples with higher ruthenium content is shifted to the near IR spectral region, while the absorption coefficient is considerably increased. The optical activity of Ru doped crystals is further reduced in comparison with undoped BTO. Photochromic effect is observed in strongly doped crystal. Photorefractive properties are experimentally investigated using two-beam coupling. Response time and diffraction efficiency are changed with ruthenium content. (C) 2002 Elsevier Science B.V. All rights reserved.
Effect of ZnMA on optical and holographic characteristics of doped PQ/PMMA photopolymer
(2005-02-01)
Hsiao, YN
;
Whang, WT
;
Lin, SH
;
材料科學與工程學系
;
電子物理學系
We report on the fabrication and experimental characteristics of doping Zinc methylacrylate (ZnMA) and 9,10-phenanthrenequinone (PQ) into a poly(methyl methacrylate) (PMMA) photopolymer. The effects of a ZnMA dopant on the optical and holographic characteristics of ZnMA/PQ/PMMA have been examined. From the optical and holographic measurements of different samples with different composition ratios, we found that the time to reach the maximum diffraction efficiency has been reduced from 102 to 59 (reduced by 1.7 times) and the diffraction efficiency has been raised up from 0.57 to 1.62% (increased by 2.9 times). We also found that holographic gratings can be recorded in pure PQ-doped PMMA, but cannot be recorded in pure ZnMA-doped PMMA. The higher the concentration of PQ in codoped PMMA, the higher the diffraction efficiency. In contrast, the higher ZnMA concentration in the codoped PMMA, the shorter the response time. It is proposed that PQ serves as a photosensitive reactant and plays a major role in the formation of phase gratings. ZnMA serves as a sufficient catalyst to accelerate the reaction of PQ with a polymer or ZnMA. By adding ZnMA with a proper concentration into a PQ/PMMA photopolymer, we succeeded in improving the holographic characteristic of the photopolymer.
Exact tests in simple growth curve models and one-way ANOVA with equicorrelation error structure
(2003-02-01)
Lin, SH
;
Lee, JC
;
統計學研究所
;
Institute of Statistics
We consider exact tests with several equicorrelation error structures and combination of equicorrelation covariance structures in simple growth curve model having single or multiple treatments and in one-way ANOVA model. Exact inferences using generalized p-values are obtained. Tests for equal treatment effects under equal equicorrelation error term and for unequal equicorrelation error terms are also developed. Two examples are given to illustrate the importance of our results. According to our findings, we would be better off dropping the assumption of equal variance when the heteroscedasticity is serious. Therefore, tests based on generalized p-values without the assumption of equal variance are much more powerful than tests with this assumption. (C) 2003 Elsevier Science (USA). All rights reserved.
Excitation of the NO molecule by chirped infrared laser pulses
(1999-11-01)
Lin, JT
;
Hayashi, M
;
Lin, SH
;
Jiang, TF
;
物理研究所
To explore the insights of recent experiments on the excitation of the NO molecule by chirped subpicosecond IR pulses, a corresponding theoretical study is presented. The agreements between experimental and theoretical results show the importance of the full-dimensional quantum-mechanical calculation. [S1050-2947(99)04711-3].
Experimental characterization of phenanthrenequinone-doped poly(methyl methacrylate) photopolymer for volume holographic storage
(2003-05-01)
Hsu, KY
;
Lin, SH
;
Hsiao, YN
;
Whang, WT
;
材料科學與工程學系
We present an experimental study on the photopolymer poly(methyl methacrylate) doped with phenathrenequinone molecules. Material characteristics for holographic data storage, including optical characteristics, scattering effect, relation between diffraction efficiency and number of holograms, and exposure schedule for multiple storage, are investigated. An experimental demonstration of multiple storage of digital data pages in a polymer cube is presented. (C) 2003 Society of Photo-Optical Instrumentation Engineers.
Experimental observation of the slowdown of optical beams by a volume-index grating in a photorefractive LiNbO3 crystal
(2000-11-01)
Lin, SH
;
Hsu, KY
;
Yeh, P
;
電子物理學系
;
光電工程學系
We investigate the group velocity of light in a one-dimensional volume-index grating inside a photorefractive LiNbO3 crystal. The slowdown of the group electromagnetic propagation is observed experimentally by tuning of the wave number of the optical beam close to the outside edge of the forbidden bandgap. We obtain a large group index of up to 7.5 in a 3.5-cm crystal sample. The group index is compared with the result of a theoretical derivation. The results are presented and discussed. (C) 2000 Optical Society of America OCIS codes: 050.7330, 260.2030, 190.5530, 160.3730.
General solution of contradirectional two-wave mixing with partially coherent waves in photorefractive crystals
(1997-06-01)
Yi, XM
;
Yang, CX
;
Yeh, PC
;
Lin, SH
;
Hsu, KY
We investigate contradirectional two-wave mixing with partially coherent waves in photorefractive crystals. By use of a statistical theory on linear systems, a general formulation of the problem in the space and frequency domain is derived and implemented numerically. We obtain results on beam intensity and mutual coherence. The results on the enhancement of mutual coherence are compared with previous theoretical results on simpler cases and with experimental measurements. Excellent agreements are achieved. The results also indicate that the effective interaction length can be significantly longer than the coherence length of the waves. (C) 1997 Optical Society of America.