To see the other types of publications on this topic, follow the link: Asymmetric couplers.
Dissertations / Theses on the topic 'Asymmetric couplers'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Asymmetric couplers.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Pelegrina, Bonilla Gabriel [Verfasser]. "Asymmetric fused fiber couplers for wavelength- and space-division multiplexing / Gabriel Pelegrina Bonilla." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2015. http://d-nb.info/1077017774/34.
Full text
2
Mak, William Chi Keung Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Coupled Solitary Waves in Optical Waveguides." Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 1998. http://handle.unsw.edu.au/1959.4/17494.
Full textAbstract:
Soliton states in three coupled optical waveguide systems were studied: two linearly coupled waveguides with quadratic nonlinearity, two linearly coupled waveguides with cubic nonlinearity and Bragg gratings, and a quadratic nonlinear waveguide with resonant gratings, which enable three-wave interaction. The methods adopted to tackle the problems were both analytical and numerical. The analytical method mainly made use of the variational approximation. Since no exact analytical method is available to find solutions for the waveguide systems under study, the variational approach was proved to be very useful to find accurate approximations. Numerically, the shooting method and the relaxation method were used. The numerical results verified the results obtained analytically. New asymmetric soliton states were discovered for the coupled quadratically nonlinear waveguides, and for the coupled waveguides with both cubic nonlinearity and Bragg gratings. Stability of the soliton states was studied numerically, using the Beam Propagation Method. Asymmetric couplers with quadratic nonlinearity were also studied. The bifurcation diagrams for the asymmetric couplers were those unfolded from the corresponding diagrams of the symmetric couplers. Novel stable two-soliton bound states due to three-wave interaction were discovered for a quadratically nonlinear waveguide equipped with resonant gratings. Since the coupled optical waveguide systems are controlled by a larger number of parameters than in the corresponding single waveguide, the coupled systems can find a much broader field of applications. This study provides useful background information to support these applications.
3
Allan, Sardonia, and Mursal Wali. "Vision om jämställdhet - en illision? : En kvalitativ studie om jämställdhet inom samboförhållanden." Thesis, Örebro universitet, Institutionen för humaniora, utbildnings- och samhällsvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-25781.
Full textAbstract:
This qualitative study was conducted to investigate how subordination and superiority emerges in the interaction between heterosexual couples between 20 to 30 years old, without children. Eight semi-structured interviews with four couples have been conducted to provide insight into how subordination and superiority is made in the interaction between the cohabiting couples. All interviews were transcribed and then manually categorized along specific main themes and sub themes. The empirical data were then assayed by a hermeneutic interpretation. Three previous studies have formed the basis for this study, Det kallas kärlek by Carin Holmberg, the anthology, Jämställdhetens pris and Familjer i tiden by Christine Roman and Helen Peterson. The theoretical framework consists symbolic interactionism, and especially the concept of asymmetrical role-taking and also doing gender. By using these theories, we can gain knowledge about the interaction between the pairs. We have also enlisted the aid of the theory doing gender to gain an understanding of how household distribution of the pairs look like. The analysis of the empirical material showed that the majority of the women were the initiator in the relationship, with regard to housework and leisure. It was also in the female and male informants' statements that the primary responsibility for the division in terms of housework was on the women. In this way, one can, using the theory of asymmetric role- taking, identify the subordination of the woman in the relationship.
4
Coetzee, Nicola. "Asymmetrical S-band coupled resonator filters." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/2287.
Full textAbstract:
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005.Due to a more densely packed frequency spectrum, there is an increasing demand for narrow band filters with asymmetrical transfer function characteristics. The resulting coupling matrices contain both positive and negative couplings, cross couplings and individual resonator frequency offsets.
5
Isbiliroglu, Yigit D. "Coupled Soil-Structure Interaction Effects of Symmetric and Asymmetric Buildings In Urban Regions." Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/268.
Full textAbstract:
This thesis deals with the response of idealized building clusters during earthquakes, their effect on the ground motion, and how individual buildings interact with the soil and with each other. We simulate the ground motion during the 1994 Northridge earthquake and focus on the coupled response of multiple simplified symmetric and asymmetric building models located within the San Fernando Valley and the Simi Valley. We use the Domain Reduction Method (DRM) in order to perform these simulations efficiently while recurrently modifying the models without having to redo the entire simulation every time. Numerical results show that the soil-structure interaction (SSI) effects vary with the number and dynamic properties of the buildings, their separation, and the impedance with respect to the soil. These effects appear as: (i) an increased spatial variability of the ground motion; and (ii) significant reductions in the buildings’ base motion at high frequencies, changes in the higher natural frequencies of the building-foundation systems and variations in the roof displacement, with respect to those of the corresponding rigid-base and single SSI models. Torsional coupling of the asymmetric structures combined with SSI effects are also investigated, and results, in comparison with the symmetric structures, are given.
6
Kogan, Anya V., and Anya V. Kogan. "Frontal EEG Asymmetry and Communication Patterns During Discussion of Disagreements in Romantic Partners." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/620878.
Full textAbstract:
Relationship conflict puts individuals at risk for emotional distress and physical illness. Although many studies in the field have focused on examining cardiovascular, endocrine, and immunological changes associated with relationship conflict, the role of central nervous system processes in relationship functioning remains vastly underexplored. The present study examined frontal electroencephalographic (EEG) alpha asymmetry during discussions of disagreements in romantic partners. Asymmetrical brain activity over the frontal cortex has been conceptualized in the literature as both a trait and state indicator of approach and withdrawal behaviors, with relatively greater left than right frontal activity corresponding to approach behaviors and relatively less left than right frontal activity corresponding to withdrawal behaviors. It was hypothesized that during discussions of disagreements in romantic partners, relatively greater left than right frontal activity would be associated with approach of discussion whereas relatively less left than right frontal EEG asymmetry would be associated with avoidance of discussion. It was also hypothesized that partners would engage in higher level of approach behaviors and exhibit relatively greater left than right frontal activity during discussion of the issue in the relationship that they chose to discuss relative to the issue chosen by their partner. Fifty heterosexual college couples in romantic relationships for at least two months came to the laboratory for a 2.5-hour experimental session, during which self-reported measures were administered, EEG activity was recorded continuously from both partners, and interactions were video-recorded. Participants were asked to engage in 2 discussions of topics on which they disagreed, in counterbalanced order, and each partner was given an opportunity to select an issue to be discussed (Her Issue vs. His Issue). After each discussion, participants were asked to watch a video-recording of their discussions and rate themselves continuously, using a computer mouse, on how much they approached and avoided the discussion. After excluding left-handed participants and data unusable due to equipment failure, data from 25 couples were analyzed. Consistent with the study hypothesis, during discussion of Her Issue, in female partners, greater self-reported rating of approach of discussion was associated with relatively greater left than right frontal activity at F4-F3 and F2-F1 EEG leads. However, there was no significant association between rating of approach of discussion and frontal EEG asymmetry at any of the sites in males during Her Issue, and no effects of rating of approach of discussion on frontal EEG asymmetry at any of the sites during His Issue in either males or females. Consistent with the study hypothesis, both female and male participants evidenced greater rating of approach of discussion during the issue they chose to discuss relative to their partners' issue. Additionally, consistent with the study prediction, males evidenced relatively greater left than right frontal activity measured by the overall asymmetry across 4 regions as well as at F6-F5, F4-F3, and F2-F1 during His Issue relative to Her Issue, and females exhibited greater relative left frontal activity at F8-F7 during Her Issue relative to His Issue. However, there were no significant differences in level of frontal EEG asymmetry measured at other EEG sites. There was a significant positive association between own approach of discussion, as derived from a self-report measure of Demand-Withdraw, and relatively greater left than right frontal activity at F8-F7, F6-F5, and F4-F3 during Her Issue but not His Issue. The current study provided partial support for the association between approach and withdrawal interactions and frontal EEG asymmetry during discussions of disagreements in romantic partners. Future studies should establish whether patterns of changes in frontal EEG activity associated with these interactions have an effect on relationship quality and satisfaction, partners' ability to resolve disagreements, and partners' psychological and physical health.
7
Liu, Zhihua. "THE DESIGN AND SYNTHESIS OF NOVEL UNNATURAL AMINO ACIDS AND THE DESIGN AND SYNTHESIS OF PEPTIDES & PEPTIDOMIMETICS CONTAINING UNNATURAL AMINO ACIDS FOR THE STUDY OF G-PROTEIN COUPLED RECEPTORS." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/204274.
Full textAbstract:
Nature has gifted peptides as important modulators in the human body, but these types of molecules often have not been favored when we were looking for therapeutic agents. The poor bioavailability, fast degradation and until recent high manufacturing costs of some bioactive peptides lowered their potential usage in the health industry. Under these circumstances, unnatural amino acids were developed as indispensible tools providing enormous support to peptide science. By incorporating proper unnatural amino acids into a peptide or protein, we now can significantly improve peptide's or protein's half-life, cell permeability, bio-distribution, etc. In addition, their potency and receptor/acceptor selectivity could also be enhanced. Site-specific modifications of peptides and proteins under physiological conditions with the use of unnatural amino acids also have been made easier with the advance of biotechnology. Therefore, my research described in this dissertation contributes to the efforts in the development of novel unnatural amino acids. In particular, I have focused on novel methods in the synthesis of anti beta-functionalized gamma,delta-unsaturated amino acids. These amino acids have special interests in peptide chemistry: they can provide conformational constraints to the peptide 3D structures; the beta-functionalization allows the introduction of pharmaceutically interesting side chain groups; and the terminal double bond which is orthogonal to peptide synthesis provides access to further chemical modifications. Two general methodologies for the synthesis of both racemic and optically active anti beta-functionalized gamma,delta--unsaturated amino acids were developed by using the thio-Claisen rearrangement (TCR) reaction. Excellent diastereoselectivies and enantioselectivities were obtained when C2-symmetric chiral auxiliaries were selected to control the stereochemistry outcome. The mechanism and the scope of the TCR reaction were also studied, showing unique advantages in the preparation of these biological interesting amino acids.Another effort of developing angiotensin II type 1 (AT1) receptor biased peptide ligands is also documented in this dissertation. The AT1 receptor is a 7-transmembrane G-protein coupled receptor, which recent researches have shown could be activated through a beta-arrestins only, but G-protein independent, pathway. We synthesized 12 analogs of Sar1,Ile4,Ile8-AngII (SII), and tested them in biological assays, and obtained valuable information for further "perfect" biased ligands design.
8
Nsibi, Mohamed Ali. "Asymmetric magnetic domain walls motion in a two-dimensional geometry : causes and effects." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY047.
Full textAbstract:
L’étude du déplacement par le courant électrique des parois de domaine magnétique a généré beaucoup d’intérêt depuis l’observation de leurs importantes vitesses de déplacement dans des multicouches ayant une asymétrie d’inversion verticale (SIA). Cet intérêt se justifie par leur fort potentiel pour de nouvelles applications à basse consommation d’énergie en mémoire cache ou mémoires centrale. L’inversion de symétrie (SIA) induit deux mécanismes dont l’action conjointe permet de déplacer efficacement les parois de domaines. Il s’agit d’une contribution énergétique chirale, appelée l’interaction Dzyaloshinskii-Moriya (DMI), et des couples de spin-orbite (SOT). Ce modèle reste incomplet vu qu’il n’explique pas plusieurs résultats expérimentaux. De plus, une contribution dissipative chirale appelée l’amortissement anisotrope, également induite par la SIA, a été proposée récemment et dont le rôle, sous courant, n’as pas encore été étudié.Le but de ce travail a été d’amener une connaissance détaillée des différentes interactions en jeu dans la dynamique des parois de domaine. Pour cela, j’ai étudié la propagation de parois sous courant dans une géométrie non colinéaire. Cette étude a été réalisée dans des systèmes ayant des SIA différentes (Pt/Co/Pt et Pt/Co/AlOx). Dans cette géométrie, j’ai observé l’asymétrie du déplacement qui illustre la compétition entre les contributions chirales d’énergie et d’amortissement dans des multicouches à faible SIA. Quant aux multicouches à forte SIA, l’asymétrie ne peut être expliquée par l’action conjointe de DMI et SOT même dans le régime à forte mobilité. Une des conséquences de ce type de déplacement est de contribuer à la déviation des bulles de skyrmion en mouvement. Nous avons appelé cet effet l’effet Hall extrinsèque des skyrmions.En mettant en évidence de nouveaux effets induits par SIA, les résultats de cette thèse contribuent à une meilleur compréhension des mécanismes intervenant dans les déplacements des parois et des skyrmions sous courant dans les multicouches magnétiquesThe study of the current-induced magnetic domain walls motion has attracted a lot of interest since the report of their large velocities of motion in thin layers with structural inversion asymmetry (SIA). This interest comes from their high potential for low power consumption functionalities in cache and main memories applications. The SIA induces two mechanisms whose combined action allows to drive efficiently the domain walls. The two mechanisms are the chiral energy term, called the Dzyaloshinskii-Moriya interaction (DMI), and the spin-orbit torques (SOT). This model is still incomplete since it does not explain several experimental results. In addition, a chiral dissipation term called the chiral damping, also induced by SIA, has recently been proposed. However, its effect on current-induced domain wall motion has not been studied.The objective of this work was to bring a more detailed understanding of the interactions involved in the domain wall motion. To that end, I have studied the domain wall motion in a non-collinear geometry with respect to the current, in materials with different SIA (Pt/Co/Pt and Pt/Co/AlOx). This motion has been found to be asymmetric. It illustrates the interplay between chiral energy and chiral dissipation in current-induced domain wall motion in weak SIA materials. In large SIA materials, the DMI and SOT model, even in the flow regime of motion, cannot explain this asymmetry. I have also evidenced that the asymmetric non-collinear domain wall motion induces a well-defined deflection of the skyrmion bubbles. This is the first observation of the extrinsic skyrmion Hall effect.The results of this thesis contribute to the understanding of the physical mechanisms behind domain wall and skyrmion motion in ultrathin layers by evidencing supplementary effects from SIA
9
Pile, David Fujio Pelleas. "Extremely asymmetrical scattering of waves in periodic Bragg arrays." Queensland University of Technology, 2003. http://eprints.qut.edu.au/15794/.
Full textAbstract:
This thesis fills in the gaps in the existing theory of wave phenomena in thick diffraction gratings at extreme angles of scattering, i.e. when the scattered wave propagates parallel or almost parallel to the grating boundaries. A consistent theory of a new type of Bragg scattering of bulk and guided optical modes in thick uniform and non-uniform, dissipative and non-dissipative, slanted periodic gratings has been developed. This type of scattering is
called extremely asymmetrical scattering (EAS).
One of the main distinctive features of EAS is the strong resonant increase of the scattered wave amplitude compared to the amplitude of the incident wave. Several unique combinations of strong resonances shaping a complex multi-resonant pattern of EAS in different types of gratings have been predicted and investigated theoretically and numerically. This includes the prediction of a new resonant wave effect in non-uniform gratings with varying phase – double-resonant EAS, the discovery of several sharp and strong resonances with respect to scattering angle in gratings with the scattered wave
propagating almost parallel to the grating boundaries (grazing-angle scattering (GAS)) for the case of second-order scattering, and the prediction of a new type of eigenmode in gratings with second-order scattering (especially in gratings with large amplitude). In addition, several other important practical problems that may be crucial for the experimental observation and application of EAS and GAS have been solved. These are the determination of the tolerance of EAS to small grating imperfections, e.g., fluctuations of the grating amplitude, prediction
of unusually high sensitivity of second-order EAS to small variations of mean structural parameters, determination of the effect of weak dissipation on EAS, etc. Physical reasons for the predicted resonances and effects are explained. In particular, the crucial role of the diffractional divergence for EAS and GAS has been revealed, especially for non-uniform gratings.
Methods of analysis involve the approximate and rigorous approaches. The approximate method is based on understanding the role of the diffractional divergence in the geometry of EAS and the two-wave approximation (valid for any types of waves). The rigorous approach is based on the rigorous coupled-wave analysis (RCWA) and, in particular, the known enhanced T-matrix
algorithm (by Moharam, et al.) that is numerically stable for narrow and wide gratings with arbitrary amplitude (valid only for bulk electromagnetic waves).
10
Kurlemann, Nils. "Evaluation of C-C-bond coupling enzymes as reversibly immobilised biocatalysts and for the application in a coupled asymmetric alkene oxidation." Berlin mbv, 2008. http://d-nb.info/990627527/04.
Full text
11
Fernández, Ana María. "Asymmetries among homosexual men and women in subjective distress to sexual and emotional infidelity: A critical test of evolutionary hypothesis." CSUSB ScholarWorks, 2000. https://scholarworks.lib.csusb.edu/etd-project/1616.
Full text
12
Branham, Stacy Marie. "Designing Technologies for Empathic Communication." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/51750.
Full textAbstract:
If you have ever used your phone while on a date to send a text message, or snapped a picture with a friend to upload to Facebook, or cut a sentence down to 140 characters to broadcast on Twitter, you may agree with some leading Social Scientists that technology is changing the way we relate with one another. Our interactions through technology seem to be getting increasingly short with less sophisticated language. More and more, our thoughts are broadcast to everyone instead of intended for someone special. Yet, there is something profoundly human and central to our development that is neglected in these interchanges. Close human relationships---with families, significant others, friends---need complex, intimate, ongoing conversations in order to create and maintain empathic connectivity. In these types of conversations, individuals become part of one another, defined by each other. Together, they change, they grow, they find meaning in life. This is, in essence, what I call Empathic Communication.
Until now, this concern has been largely neglected in the field of Human-Computer Interaction, a community of researchers and technology designers who are arguably best positioned to address it. To suggest one path forward, in this dissertation I raise the question of whether computer technologies can become brokers of Empathic Communication between people who care about each other, with a specific focus on intimate partners. How can we conceptualize Empathic Communication, how can we build tools that support it, and how do we know if we have succeeded?
I address these questions by creating a simplified model of the therapeutic process of intimate reconnection, or the 4Rs framework---Repattern, Reflect, Restory, Reconnect. Using the 4Rs framework as an ideation tool, I designed and field-tested a technology concept for a dyadic journaling application, Diary Built for Two, that might help romantic partners reconnect through deep communication. Using the 4Rs framework as an evaluation tool, I found that Diary Built for Two enabled more intimate, more thoughtful, more Empathic Communication that changed the way partners saw themselves, one another, and their relationship. Unexpectedly, I found that research interviews I conducted with intimate partners had the same type of therapeutic effect. Simply asking partners questions about their relationship caused them to reflect on and change their understandings of their relationship and each other.
To guide other researchers and designers of Empathic Communication Technologies (ECTs), I present a set of specific outcomes of my study. First, I present Symmetric and Asymmetric interface profiles, which identify new human-technology configurations that may better support deep communication---for example, having one shared device between two people, as opposed to one separate device for each. I also share some of the ways in which research interviews may positively and negatively affect study participants towards reconsidering current informed consent practices. Both of these findings showcase the utility of selectively conceptualizing our technology designs as well as our research methods as therapeutic interventions; when we apply the therapy metaphor, new design and research opportunities become apparent.Ph. D.
13
Goodman, Steven John. "Resonances of scattering in non-uniform and anisotropic periodic gratings at extreme angles." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16429/.
Full textAbstract:
Bragg scattering of optical waves in thick gratings at extreme angles, where the scattered wave propagates parallel (extremely asymmetric scattering - EAS) or nearly parallel (grazing angle scattering - GAS) to the grating boundaries, is associated with many unique and practically important resonant phenomena. It has been demonstrated that one of the main physical mechanisms for these resonant phenomena is the diffractional divergence of the scattered wave inside and outside the grating region. This thesis fills the gaps in the theoretical and experimental understanding of Bragg scattering in gratings at extreme angles by investigating EAS and GAS in structures where diffractional divergence of waves is significantly affected by anisotropy and/or non-uniformities of the dielectric permittivity.
Unusually high sensitivity of wave scattering in thick periodic gratings to small step-like variations of mean structural parameters at the grating boundaries is predicted and described for the case when the scattered wave (the +1 diffracted order) propagates almost parallel to the front grating boundary (the geometry of GAS). A unusual pattern of strong multiple resonances for bulk electromagnetic waves is predicted and analysed numerically in thick periodic holographic gratings in a guiding slab with mean permittivity that is greater than that of the surrounding media. It is demonstrated that these resonances are related to resonant generation of a new type of eigenmodes in a thick slab with a periodic grating. These eigenmodes are generically related to the grating -- they do exist not if the grating amplitude is zero.
A new type of resonant coupling of bulk radiation into the conventional guided modes of a slab with a thick holographic grating is predicted and explained theoretically. It occurs in the presence of strong frequency detunings of the Bragg condition by means of interaction of the strongly non-eigen +1 diffracted order with the slab-grating boundaries. Therefore, it is only in the presence of step-like variations of the mean permittivity at the grating boundaries that this type of resonant coupling can occur.
A new method for the analysis of EAS and GAS in anisotropic gratings is developed. This method is based on the consideration of the diffractional divergence of the scattered wave and the two-wave approximation in anisotropic gratings. Special efforts are focused on the analysis of EAS and GAS of extraordinary waves in uniaxial gratings. In particular, it is demonstrated that increasing curvature of the normal surface in the direction of propagation of the scattered wave results in increase of its diffraction divergence and the resonant amplitude.
A theoretical model is developed for comparison of the theoretical predictions with data obtained from experimental observations of EAS in a holographic grating written in a photorefractive medium. The developed model is applied for the interpretation of experimental observations of EAS in BaTiO3 photorefractive crystals. Good agreement with the theoretical predictions is demonstrated.
14
Shie, Ming-Fung, and 謝明峰. "The effect of the asymmetric on polymer asymmetric Bragg couplers." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/hyfy9s.
Full textAbstract:
碩士國立虎尾科技大學
機械與機電工程研究所
98
This thesis describes a procedure to fabricate a polymer asymmetric Bragg couplers and Research it’s properties. In this study,the grating structure on a polymer is fabricated first by using holographic interferometry and micro-molding processes. The polymeric wavelength filters are produced by a two-step molding process where the master mold is first formed on a negative tone photoresist and subsequently transferred to a PDMS mold; following this step, the PDMS silicon rubber mold was used as a stamp to transfer the pattern of the polymeric wavelength filters onto a UV cure epoxy,to complete the polymer optical waveguide devices. Next, We change the asymmetry of the two parallel waveguides,to make the two decoupled waveguides quite dissimilar to avoid the spectrum overlapping.The profiles of the devices were observed using SEM and AFM system. The optical transmission characteristics were measured in terms of Tunable Laser spectrum analyzer. BPM-CAD (Beam propagation method) analysis was used to simulate and the theory results only have small different compared with the experiment results.
15
Tsai, Meng-Chu, and 蔡孟舉. "A study of Asymmetric Polymer Waveguide Couplers with Bragg Reflectors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/t7uz8r.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
101
This study MEMS technology – based, using the photolithography process to fabricate waveguide channel, combined with soft lithography process technology in micro contact printing and replica molding technology, use of polydimethysiloxane ( PDMS) reprographic copying the waveguide channel to polymer materials, then with Holographic Interference Lithography to cycle adjustable and a large area production, making the bottom of the waveguide diffraction grating, the one waveguide channel have raster, another not of non-symmetrical structure, working conditions in conformity optical drop multiplexer works, then use of the above process technology can achieve the process simple and fast, and low cost price objective. In the experiment, we use the Field Emission Scanning Electron Microscope (FE-SEM) and Atomic Force Microscope (AFM) to observe the waveguide structure and the diffraction grating depth and period, finally using near-field coupling measurement technique to observe the polymer waveguide optical saturation intensity reflective element, then use Tunable Laser as light source and measuring the penetration waveguide grating spectrum and influence is reflected back through the reflection spectrum.
16
Hsiao, Yu-Tao, and 蕭裕韜. "Study of Dual-Chanel filters based on High Asymmetric Bragg Couplers." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/bhz7jv.
Full textAbstract:
碩士國立虎尾科技大學
光電工程系光電與材料科技碩士班
104
In this paper, analysis and investigate of polymer waveguide asymmetric structure, in MEMS process technology as the foundation, the use of photolithography process making waveguide structure and waveguide structure reprint onto the polymer material, the waveguide structure of this Device of each coarse end of and the fine end of composition, reuse holographic interference lithography technology to produce a Bragg grating in the crude end of the waveguide at the bottom, and no fine end of to form an asymmetric structure. Filling different materials during the manufacturing process on the waveguide structure, high refractive index of the light guide layer and a light guide layer coated on the low refractive index of cladding layer constituting the elements, whereby the results of the research measured. In this study, using Atomic Force Microscope(Atomic Force Microscope, AFM) to observe element’s diffraction grating depth and period, and 3D rendering of grating structure ; scanning electron microscope(Field Emission Scanning Electron Microscope, FE-SEM) to observe fine waveguide structure, and adopting near-field coupling measurement technique to observe the light saturation intensity, then use Tunable Laser to measure light penetrate through the grating reflection spectrum back to the end of the reflection spectrum and capture the output.
17
Kao, Wei-mei, and 高薇湄. "The effect of the waveguide gap and asymmetric on the coupling efficiency of polymer asymmetric Bragg couplers." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/71118057877153279903.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
98
In this work, we successfully developed a process to fabricate dual-channel polymeric waveguide filters based on an asymmetric Bragg coupler (ABC) using holographic interference techniques, soft lithography and micro molding. We also obtain the influence of the waveguide gap and asymmetric on the coupling efficiency of polymer asymmetric Bragg coupler. In this experiment, the grating structure on a polymer is fabricated first using holographic interference techniques and micro molding processes. Next, we will fabricate an asymmetric Bragg coupler device through photolithography process and soft lithography on a thick film photoresister. Finally, the grating profiles of the devices were observed using SEM and AFM system. The optical transmission characteristics were measured in terms of Tunable Laser spectrum analyzer. At the cross- and self-reflection Bragg wavelengths, the transmission dips of approximately –16.4 and –11.5dB relative to the -3dB background insertion loss and the 3dB transmission bandwidths of approximately 0.6 and 0.5nm were obtained from an ABC-based filter. The transmission spectrum overlaps when the effective index difference between two single waveguides is less than 0.002.
18
Liao, Che-Yi, and 廖哲毅. "The Effect of The Different Core Layer on Polymer Asymmetric Bragg Couplers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/823mkt.
Full textAbstract:
碩士國立虎尾科技大學
機械與機電工程研究所
100
This thesis describes a procedure to fabricate a polymer asymmetric Bragg couplers and Research it’s properties. In this study, the grating structure on a polymer is fabricated first by using holographic interferometry and micro-molding processes. The polymeric wavelength filters are produced by a two-step molding process where the master mold is first formed on a negative tone photoresist and subsequently transferred to a PDMS mold; following this step, the PDMS silicon rubber mold was used as a stamp to transfer the pattern of the polymeric wavelength filters onto a UV cure epoxy, and to complete the polymer optical waveguide devices. Next, We have filled the different optical polymer in two parallel waveguides(SU-8 2005、SU-8 3005), to make the effective refractive index of two parallel waveguides quite dissimilar to avoid the spectrum overlapping. The profiles of the devices were observed using SEM and AFM system. The optical transmission characteristics were measured in terms of Tunable Laser spectrum analyzer. OptiBPM (Beam propagation method) analysis was used to simulate and the theory results only have small different compared with the experiment results.
19
Chang, Chien-Wen, and 張建文. "Design of Dual Band Branch-Line Couplers Based on Asymmetric Spur Lines." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/19630838853497797702.
Full textAbstract:
碩士國立高雄第一科技大學
電子工程研究所
103
This paper presents the design of dual band branch-line couplers. In the proposed design, all asymmetric spur lines and conventional branch lines are only a quarter-wavelength long(λ).Both of them equal to each other.Asymmetric spur lines structure used asymmetric coupled lines to improve and conventional circuit consisted of a branch line merging parallel open stub. In theory, it can be acquire actual size from simulation. However, symmetric spur lines were derived by asymmetric spur lines in appropriate condition. To support implement circuit from impedance relationship between the two. According to the proposed design methods, realizing the purpose of dual-band, etc. In this paper, select the common frequency specifications on dual band branch-line circuit. Asymmetric spur branch-line coupler divided into dual band frequency. The first circuit operating at f2/f1=2GHz/0.9GHz, the result of the measurement in lower band is S11=-19.134dB、S21=-3.745dB、S31=-20.051dB、S41=-3.764dB,the phase difference of∠S21-∠S41=94.781°, bandwidth of 60MHz, in upper band is S11=-19.379 dB、S21=-4.557dB、S31=-16.998dB、S41=-4.507dB﹐the phase difference of ∠S21-∠S41=85.752°﹐bandwidth of 63MHz, asymmetric spur branch-line coupler as practical as conventional. The second circuit operating at f2/f1=2.4GHz/1.8GHz, the result of the measurement in lower band is S11=-22.638dB、S21=-3.778dB、S31=-17.675dB、S41=-3.7834dB, the phase difference of∠S21-∠S41=87.071°, bandwidth of 190MHz, in upper band is S11=-15.409dB、S21=-4.88dB、S31=-15.01 dB、S41=-4.9dB, the phase difference of∠S21-∠S41=84.248°,bandwidth of 60MHz. The second circuit as practical as conventional and to reduce the ratio of both upper and lower band. The spur lines improved conventional circuit that two frequency too close, causing the Open-circuit stub impedance is too large. And it can further study to pursuit low cost, easy fabrication in the future.
20
Kuo, Jih-Sheng, and 郭日升. "Comparison of numerical simulation and experiments of asymmetric light couplers for sunlight collection." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/cu9u2z.
Full textAbstract:
碩士國立臺北科技大學
光電工程系研究所
102
Because of global warming and energy shortage, energy saving and carbon reduction are the most important problem of all human beings. The solution to reduce carbon emissions is to use green energy in which solar energy is the most environment-friendly. By importing sunlight into houses, we can save a lot of energy. Solar lighting system is composed of collectors, light couplers, and light exits. Daylight illumination system must provide sufficient sunlight, especially in indoor lighting of the building. The key to increase the amount of accumulated sunlight is to use a large number of light collectors and optical couplers. If we can reduce the transmission loss of sunlight, we will be able to increase the amount of daylight. However, there are not many researches for solving the light transmission loss. By using the simulation results show that the efficiency increases as the incident angle decreases for the light traveling form the trunk into the coupling region with a large coupling angle. On the other hand, the efficiency increase as the incident angle increases for the light traveling form the branch into the coupling region with a large coupling angle. Compared with the previous work by Shen, the simulation results conducted by the formulas presented in the thesis only exited 0.17% difference of efficiency of the coupler with coupling angle 5°. Excerpt for the slightly difference of coupling efficiency, the calculation speed was increased about 273 times faster than the previous work. We can identify whether enter light pass the coupler region or not. After we compared the numerical simulation and experimental results, we found that the efficiency of the numerical simulation of the experimental decreased by about half, but the trend matched. According to the result of the experiment, it showed the correctness of this calculation formula.
21
LUO, YU-WUN, and 羅鈺雯. "A Study of Optical Filters Based on Asymmetric Bragg Couplers with Liquid Crystal Tuned Spectra." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4gb9d4.
Full text
22
Lee, Chieh-Hsun, and 李杰勲. "The study of broadband polarization beam splitters based on asymmetric adiabatic couplers in Ti-diffused lithium niobate waveguides." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/h3zepj.
Full textAbstract:
碩士國立中央大學
光電科學與工程學系
106
In this study, the structure of asymmetric adiabatic coupler (AAC) is designed using the concept of Stimulated Raman Adiabatic Passage (STIRAP), and applied it on the lithium niobate(LiNbO3) with the titanium diffused waveguides to become a polarization beam splitter. We designed the structure into two parts to split TE and TM polarization. Our goal is to achieve the broadband polarization beam splitter by using a two-stage structure to separate two different polarized lights. Before the fabrication process, we do the simulation part. In the simulation process, first step we use 1550 nm as the center wavelength to simulate TE and TM polarization in different structures. Second step, based on our previous simulation, we apply an adiabaticity engineering method to optimize the waveguide system configuration to achieve a broadband polarization beam splitter. Finally, we use a TE-polarized 775 nm laser as the pump to examine the structure to make sure the pump will be spatially filtered from the cross-polarized signal and idler. Furthermore, we fabricated such an AAC chip to measure the experimental result. We used the standard lithography process and titanium diffusion process to fabricate the AAC chip in a 51 mm long, 25 mm wide, and 0.5 mm thick LiNbO3 crystal. In the measurement result, we had a good-fitting result with the simulation process. It can be found a bandwidth of >120 nm can be achieved in this unique Ti:LiNbO3 polarization beam splitter at a power splitting ratio of >95% for both polarization modes, which is to the best of our knowledge the broadest bandwidth ever reported in integrated optical LiNbO3 polarization beam splitters.
23
WU, ZHE-HUI, and 吳哲暉. "Asymmetrical microstrip forward couplers." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/01696819441427601438.
Full text
24
Lin, Yu-Kai, and 林郁凱. "Fabrication of polymer asymmetric Bragg coupler." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/99x43z.
Full textAbstract:
碩士國立虎尾科技大學
機械與機電工程研究所
96
Abstract This thesis describes a procedure to replicate a polymeric wavelength filter. In this work, the grating structure on a polymer is fabricated first using holographic interferometry and micro-molding processes. The polymeric wavelength filters are produced by a two-step molding process where the master mold is first formed on a negative tone photoresist and subsequently transferred to a PDMS mold; following this step, the PDMS silicon rubber mold was used as a stamp to transfer the pattern of the polymeric wavelength filters onto a UV cure epoxy. Initial results show good pattern transfer in physical shape. Use soft molding techniques to fabricate the low loss polymer optical waveguides and Large Scale production. The optical transmission characteristics were measured in terms of Tunable Laser spectrum analyzer. The grating profiles of the devices were observed using SEM and AFM system.
25
Loan, Nguyen Thi, and 阮氏鸞. "Fabrication of the Asymmetric Bragg Grating Coupler Filter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/chrj43.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
101
Abstract In this work, we successfully fabricate an asymmetric Bragg grating coupler filter using holography interference technique, soft lithography and micro molding. The mechanism is based on Bragg reflection coupled mode theory. With different material on individual core, the tuning wavelength range could be extended. The asymmetric Bragg filter has grating period of 500nm and grating depth of 250nm. The transmission characteristic shows that the filter band centered at around 1600nm. The transmission dips of grating are about 16dB.
26
Chen, Shr-Wei, and 陳仕委. "A Fabrication of Asymmetric Bragg Coupler without Self-reflection." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/fv9p33.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
98
In this research, it is to fabricate bi-channel filters with a technology to fabricate Grating on Waveguide by using techniques of Holographic inference and Photolithography. In this experiment, it cooperate the technique MEMS fabrication and optical lithography to fabricate the master molding of polymer Waveguide along with techniques of microcontact printing, replica printing and soft printing, how it fabricated out the bi-channel filter is to stamp in the grating with waveguide mold into grating the of using photolithography formation. It is easily to achieve the mass production, easy fabrication and low cost by using technique of lift molding of polymeric Waveguide. In order to observe and record the results of this experiment accurately, we utilize the AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy).
27
Li, Jia-Han, and 李佳翰. "Electromagnetic Modeling for Asymmetrical Fused Fiber-Optic Couplers." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/15152751894620270094.
Full textAbstract:
碩士國立臺灣大學
電機工程學系
85
Based on a full-wave vectorial formulation, the surface integral equation method (SIEM) has been employed to investigate the coupling characteristics of fused fiber-optic couplers. To establish a three-dimensional (3-D) electromagnetic model for the fused coupler, the step-like approximation is used to approximate the tapered structure of the coupler into many small segments. The SIEM is employed to solve the propagation characteristics for each segment, and the mode-matching method is used to takeinto account the possible mode conversion at each discontinuity along the tapered coupler. Using this 3-D model, we theoretically study fused fiber-optic couplers with different structure parameters, in particular, the asymmetrical couplers composed of two dissmilar fibers.
28
Chang, Ting-kai, and 張庭凱. "Polarization beam splitter based on a dielectric loaded asymmetric directional coupler." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/64009704113521822153.
Full textAbstract:
碩士國立臺南大學
電機工程學系碩士班
101
A polarization beam splitter (PBS) based on asymmetrical directional coupler (ADC) is proposed by utilizing the different aspect ratios between a wide waveguide and a dielectric loaded narrow waveguide. The TM mode is design to be well coupled in the ADC. Meanwhile, the large phase mismatched TE mode results in negligible coupling. Finally, We connect S-bent waveguide at the end of the coupling region to make the two waveguides separated far enough. The simulation results show that the present PBS has a high extinction ratio of more than 20 dB, and the device length is less than 10 μm. The PBS has a bandwidth range of about 100nm, and fabrication tolerance of about 77nm for the extinction ratio is greater than 10dB.
29
Majeed, Asmaa H., Abdulkareem S. Abdullah, Fauzi Elmegri, Khalil H. Sayidmarie, Raed A. Abd-Alhameed, and James M. Noras. "Aperture-Coupled Asymmetric Dielectric Resonators Antenna for Wideband Applications." 2014. http://hdl.handle.net/10454/8422.
Full textAbstract:
yesA compact dielectric resonator antenna (DRA) for wideband applications is proposed. Two cylindrical dielectric resonators which are asymmetrically located with respect to the center of a rectangular coupling aperture are fed through this aperture. By optimizing the design parameters, an impedance bandwidth of about 29%, covering the frequency range from 9.62 GHz to 12.9 GHz, and a gain of 8 dBi are obtained. Design details of the proposed antenna and the results of both simulation and experiment are presented and discussed.
30
李恭儀. "Multiple tunneling and chaos in asymmetric coupled quantum wells." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/09669899326186103253.
Full text
31
Ding, Yan-Wun, and 丁彥文. "Fabrication of an Asymmetric Bragg Coupler Filter with non-identical Core Materials." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/q9j74k.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
102
In this study, a negative photoresist with photolithography process technology waveguide structure and the use of soft lithography die-stamping Holographic Interference Lithography technology combines the advantages of adjustable cycle and its large area production, etc., to produce optical add-drop multiplexer element waveguide structure of this element into the input and output side, there are two channels of a thin a thick, coarse end of the waveguide at the bottom of the use of holographic interference lithography to produce Bragg Grating at the bottom of the channel, as a whole showed a grating and the other a no structural grating, this asymmetric conditions of light drop multiplexer consistent operating conditions, which can be made out of this study that the structure can achieve it works. After completion of the waveguide element is made of a high refractive index of the light guide layer and the cladding layer and a low refractive index optical guide layer composed of approvals, the photoconductive layer is usually made of a material composed of a single high refractive index, this study was in the short-side optical guide layer thick bottom Bragg grating regions of different refractive index materials on the cover, thereby to study and explore the impact element. In this study we used the atomic force microscope to obtain a cycle and the depth of a Bragg grating , but also using a field emission scanning electron microscope to observe and investigate the waveguide structure, Finally, the measurement part , the use of tunable laser as the light source to measure the penetration tunable Laser spectrum and waveguide components reflected by the grating influence the reflection spectrum.
32
Lin, Chi-Hsing, and 林其興. "A study of asymmetric Bragg coupled device with polymer waveguides." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/7xeb56.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
96
In this research, we propose a novel technique of fabricating an asymmetric Bragg coupler device by using holographic technique and master molding of soft printing along with the photolithography. First, we produce out a polymeric Bragg Grating by Holographic lithography and then carried out a master mold of a Bragg Grating associated with techniques of micro-contact printing, micro-molding in capillaries and replica molding. While successfully fabricated a master mold of polymeric Grating component, we fabricated an asymmetrical waveguide coupler on the grating using photolithography with thick film photoresist. In this experiment, the waveguides thickness were controlled by different spinning speeds thereby, a comparison of efficiency was made in each waveguide. It is easily to achieve the mass production, easy fabrication and low cost by using technique of lift molding of polymeric Grating. In order to observe and record the results of this experiment accurately, we utilize the AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy), and its characteristic of optical transmission can be observed by an optical measuring system.
33
Cai, Qing Bin, and 蔡清斌. "Chaotic behavior of hole mixing tunneling in asymmetric coupled quantum wells." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/86495615119265573067.
Full text
34
WANG, JUN-FU, and 王俊富. "Second-order nolinear optical susceptibilities of compositionally asymmetric coupled quantum wells." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/21033261869570018764.
Full text
35
Lee, Wei-Lun, and 李偉倫. "Directional-Coupler-Based Polarization Splitting in Asymmetric Metal/Multi-Insulator Configuration for Optical Nanocircuitry." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/25255571923920438718.
Full textAbstract:
碩士國立中央大學
光電科學研究所
100
This thesis described the design and analysis of a novel directional-coupler-based polarization splitter for optical nanocircuitry in two-dimensional (2-D) asymmetric metal/multi-insulator configuration. The design and optimization of the proposed device are conducted using 2-D finite-element-based numerical simulations while modified coupled-mode theory for lossy parallel waveguides is developed as the mathematical background of this research. The introduction of silver region in asymmetric air/silicon/silica waveguide is shown to not only enhance the field confinement but also control the dynamic range of the effective index associated with the transverse magnetic (TM) mode. A large modal birefringence of > 0.69 is estimated, enabling a clean polarization separation within 7.28 , inclusive of the input/output tapers. The proposed polarization splitter is optimized at the wavelength of 1550 nm. The transmission efficiencies of -0.1443 dB and -0.3777 dB are obtained for the respective transverse electric (TE) and TM modes while the extinction ratios and splitting ratios are larger than 20 dB at 1550 nm. Due to the excitation of the plasmonic mode, an extremely broadband operation from 1000 nm to 1800 nm is found for the TM transmission, which in turn affects directly the TM splitting ratio as well as the extinction ratio along the cross path. The TE behavior is; however, similar to that of the conventional direction coupler. The extinction ratios and extinction ratios are estimated to be larger than 15 dB for wavelengths ranging from 1502 nm to 1581 nm. The modified coupled-mode theory is derived based on the modified Lorentz reciprocity theorem suitable for describing the field perturbations in a lossy system. The application of the theory to the TE mode coupling in the present case is in good agreement with the finite-element-based numerical simulations. Specifically, the respective differences between the coupling length and power transfer along the cross path are merely 0.9652% and 0.1313% with respect to the numerical results.
36
Chan, Chi-Hung, and 詹麒宏. "New Crossover Coupler Design Using Asymmetric Branch-Line Hybrids and Its Dual-Band Operation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/04074713060043924164.
Full textAbstract:
碩士國立交通大學
電信工程研究所
98
Two asymmetric branch-line hybrids with arbitrary power divisions are cascaded for design of a crossover coupler. The two pairs of the diagonal ports are allowed to have different characteristic impedances. Block ABCD matrices are applied to estimate the bandwidth of the crossover coupler. To achieve the dual-band operation, an elementary two-port is employed to replace the ??4-section of each hybrid. The two-port consists of a stepped-impedance section with two open stubs shunt at both of its ends. By means of the transmission-line theory, analytical equations are formulated to solve the circuit parameters. A circuit designed at 0.9/1.8 GHz is realized and measured to validate the idea.
37
Yung-Chang, Sze, and 施永昌. "Quasi-Static Analysis of Asymmetric Coupled Transmission Lines by Boundary Element Method." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/70484110720701154274.
Full textAbstract:
碩士大同工學院
電機工程研究所
81
A modified boundary element method in the application of quasi- TEM analysis of microstrip coupled lines is The analytic results are then used to design the forward and backward directional coupler. Applying the coupled-mode lation of microstrip coupled lines, the directional coupler be treated as a four port network and the circuit parameters can easily be obtained. In this thesis, investigation is mainly made on the asymmetric coupled microstrip lines. The mutual inductance capacitance coupling coefficients are the two main parameters which determine the directivity of the coupler. Through our study, a new structure is presented with an aim to provide directivity. The structure is referred to an enclosed one, height of the enclosure is equal to twice the dielectric ness. It is investigated that this structure can compose an backward- coupling directional coupler so long as all four are well matched (characteristically terminated).
38
Tien, Yao Cheng, and 田曜丞. "A single photon emitter implemented by electrostatically-gate asymmetric coupled quantum well." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/59055261583259659971.
Full textAbstract:
碩士國立清華大學
光電工程研究所
104
We present the modeling of dipolar excitons in AlGaAs based, asymmetric coupled quantum wells with a vertical electric field induced two-dimensional electrostatic trap. We theoretically show that when the trap size and depth are carefully engineered, it is possible for the system to enter an exciton blockade regime in which single photon emissions can be obtained. Due to the unique properties such as the trap geometry and position can be precisely defined by photolithography, the proposed single photon emitter may find new applications in quantum information processing.
39
Haobijam, Olivia Devi, and 歐莉文. "Study of Optical Coupler Asymmetry Effects on Optical Coherence Tomography Measurements." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/24r8y8.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
99
Optical coherence tomography (OCT) is a popular method for creating real-time three-dimensional images of biological and non-biological specimens. This imaging modality uses the interference between light backscattered from a sample and light that has traversed a known reference path delay to determine the scattering profile over penetration depths up to several millimeters in biological tissues. Frequency-domain OCT (FD-OCT) is an implementation of OCT which provides advantages in signal-to-noise ratio along with faster signal acquisition than other OCT methods. In an OCT set-up, a fused-fiber optical coupler is one of the key components. Ideally the coupler should have a splitting ratio that is independent of wavelength. However all commercially available optical fiber couplers have some variations in transmission loss as a function of wavelength. This is because of configure variations in the common fabrication method for the fused-fiber coupler which involves twisting together, melting, and pulling two closely spaced single-mode or multi-mode fibers over a uniform length section. The goal of the thesis is to determine what effect any wavelength-dependent asymmetry in the operational characteristics of an optical coupler has on the OCT system performance. In this study a Frequency-domain OCT (FD-OCT) set-up, with a Michelson interferometer using a 2x2 optical fiber coupler, is used. By interchanging the orientations of the optical coupler arms in the FD-OCT set-up, a detailed experimental and simulated study was done to determine the effects of wavelength-dependent characteristics of optical couplers on the accuracy of OCT measurements.
40
Yang, Chao-Shun, and 楊超舜. "Analysis of asymmetrical coplanar coupled line for antenna applications." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/q93s3y.
Full textAbstract:
博士國立交通大學
電信工程研究所
103
So far, the coplanar waveguides (CPW) are extensively used for all kinds of microwave circuits and components, it is one of the most basic transmission lines. In the past, numerous papers had solved the analytical solution for the finite/infinite ground-plane CPW, conductor backed CPW and symmetrical multi-metal-plate CPW. There are many full-wave simulators available for evaluating arbitrarily shaped transmission-line parameters such as characteristic impedance and effective dielectric constant. However, for asymmetrical CPWs (e.g. coplanar coupled line), designers are still unable to obtain the decoupled common/differential-mode port characteristic impedance and four-port Z parameters from commercial full-wave electromagnetic field simulation software directly. This thesis utilizes the conformal mapping method of complex analysis to obtain the decoupled common/differential-mode port characteristic impedance and effective dielectric constant that can be used for planar antenna designs such as dual-band antenna, spatial filter and beam-switching antenna.
41
Wu, Sung-Lin, and 吳松霖. "Photoluminescence Study of Zn0.48Cd0.52Se/Zn0.24Cd0.18Mg0.58Se Asymmetric Coupled Quantum Well Structure Grown by MBE." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/a3zzcb.
Full textAbstract:
碩士明志科技大學
電子工程系碩士班
102
Photoluminescence (PL) was used to characterize the optical transitions in a ZnCdSe/ZnCdMgSe asymmetric coupled quantum well (ACQW) structure grown on InP substrate by molecular beam epitaxy. The PL spectra revealed the situation of the optical transition in the ACQW structures. Using Gaussian line shape to fit transition energies depends on temperatures. Then use Varshni and Bose-Einstein relation consistent transition energy depends on temperature, the parameters obtained value analysis of the optical characteristic of the transition energy of ZnCdSe/ZnCdMgSe ACQW depends on temperature and determine the reliability of the experimental data. The PL spectra for the ACQW sample in the temperature range from 10 to 300 K. The PL peak monotonically shifts toward lower energy and broadens with increasing temperature in the same temperature range above. Thus, using Varshni and Bose-Einstein formula to analyze the optical signal that fit the theory of temperature dependent characteristic from the temperature range. The parameter of boarding function to assess, analyze and discuss. Finally, study of ZnCdSe/ZnCdMgSe ACQW structure of the integrated PL intensity as a function of laser excitation power density. The relation between the integrated PL intensity and the excitation density where γ is a fitting parameter. The fitted values γ that at the measured temperature range the luminescence is dominated by exciton recombination. The results demonstrate the potential of PL techniques for the contactless and nondestructive characterization of the wide band gap II-VI QW structures for mid-IR intersubband device applications.
42
Chen, You-Rang, and 陳佑榮. "Fabrication of an Optical Add/Drop Multiplexer with Liquid Crystal in an Asymmetric Bragg Coupler Waveguide." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/g82485.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
102
In this thesis, research and analysis of polymer waveguide asymmetric structure in LIGA technology in the photolithography process, the micro-contact molding, copy forming technology, making the waveguide structure to polymer materials, and use its technology to one of the waveguide channels shelter, then the use of holographic interference lithography to fabricate waveguide Bragg gratings on the bottom, forming a non-symmetrical structure. In the process, two waveguide cores are the different materials in the waveguide elements , in the input / output side of the core, the liquid crystal with high refractive index is added, to increase the fineness of the filter . In this paper, using Atomic Force Microscope to observe element’s grating cycle, depth and 3D Rendering; with Field Emission Scanning Electron Microscope to observe the fine structure elements and the near-field observation light saturation intensity, then the output of the tunable laser penetrate through the grating reflection spectrum and capture the reflection spectrum of clients.
43
Sung, Li-Wei, and 宋立偉. "Study of 1.55 μm asymmetric couple quantum well active layer laser-modulator OEIC." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/71295556112505772690.
Full textAbstract:
碩士國立臺灣大學
電機工程學研究所
87
In this study, we realize 1.55μm DFB laser - modulator optoelectronic integration circuits by using identical active layer (IAL) approach which applies the same active layer in laser and modulator. To solve the intrinsic problem in identical active layer approach that the laser gain spectrum is too close to the modulator absorption, a novel asymmetric couple quantum well structure was designed to enlarge the separation between the gain and absorption spectrum theoretically. Then two epitaxial samples with conventional QWs and asymmetric couple QWs were grown by gas source MBE and processed to be broad area lasers and PIN photo diodes. From the measurement results of those devices, the theoretical calculation is proven. Finally, 1.55μm DFB laser - modulator optoelectronic integration circuits with 13dB Extinction ratio are demonstrated.
44
Tang, Jing-Yau, and 唐敬堯. "Fabrication of Asymmetric Bragg Coupled Devices with Polymer Waveguides by Using Micro-Molding Process." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/326yx6.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
97
In this thesis, we propose a novel technique of fabricating an asymmetric Bragg coupled devices with polymer waveguides by using master molding of soft printing with the photolithography and holographic technique. First we made a ridge waveguides component through photolithography. We used the holography interference to implement a polymer Bragg waveguide component then with micro-contact printing of the soft printing, micro-molding in capillaries and replica molding to fabricate the molding of soft asymmetric Bragg coupled device with polymer waveguides component. Finally, we utilized formed soft waveguide molding along with polymer materials to implement an asymmetric Bragg coupled devices with waveguides component. It is easily to achieve the mass production. It has some advantages including process time shortening, low cost and lowest optical loss by using technique of soft molding of asymmetric Bragg coupled devices with polymer waveguide. In order to observation of the surface grating and record the results of this experiment accurately, we utilize the AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy ). Whereas the optical transmitting features are measured through the optical measuring system.
45
Xiao, Min-Yuan, and 蕭閔元. "Silicon-on-Insulator Polarization Beam Splitter Based on a Taper Asymmetrical Directional Coupler." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/60100169290533679232.
Full textAbstract:
碩士國立中山大學
光電工程學系研究所
100
Polarization dependences of optical devices in highly-integrated optical systems become a major problem. To overcome this issue, one can implement polarization diversity scheme to achieve a single polarization on-chip network. One of the essential components in a polarization diversity scheme is the polarization beam splitter (PBS). In this thesis, we will a PBS based on a silicon-on-insulator (SOI) platform with reduced device size and broad operation bandwidth. We use the three-dimensional Finite-Difference Time-Domain (3D-FDTD) method to perform the simulation. First, we use two asymmetric waveguides to design an asymmetric directional coupler with only TE-like mode phase matching condition. We then tape the lower waveguide to keep the TE-polarized light, and split the TE- and TM- polarized light. By utilizing an asymmetrical directional coupler with a tapered waveguide, we have achieved a 7.3
46
"Graduate School Stress, Dyadic Coping, and Well-Being in Asymmetrical Graduate Student Couples." Master's thesis, 2017. http://hdl.handle.net/2286/R.I.44111.
Full textAbstract:
abstract: The demands and expectations of graduate school can be stressful for any student. Graduate students in a romantic relationship, in particular, contend with both individual and dyadic effects of graduate school stress, as stress has been found to be negatively associated with both individual and relational well-being. Asymmetrical graduate student couples, wherein one partner is in graduate school and the other is not, may be particularly vulnerable to relationship strain because of differences in their experience of graduate school. However, non-student partners can help the graduate student cope with stress through dyadic coping. This study sought to examine whether: a) there were associations between graduate school stress on individual (life satisfaction) and relational (relationship satisfaction) well-being, and b) whether these associations were moderated by positive and negative dyadic coping behaviors. Cross-sectional data from 62 asymmetrical graduate student couples were gathered using an online survey. Data were analyzed using Actor-Partner Interdependence Models (Kenny, Kashy, & Cook 2006). Separate models were conducted to examine overall associations between graduate stress and well-being, and additional analyses were conducted to examine potential moderation effects of perceptions of partner dyadic coping (actor effects) and partner self-reported dyadic coping (partner effects) on the overall associations between stress and life- and relationship satisfaction mentioned above. Results for the overall model suggested that graduate stress is associated with both individual- and relational well-being. Surprisingly, and against prior literature, positive dyadic coping did not buffer the negative association between graduate stress and well-being, and negative dyadic coping did not exacerbate the association. Implications of the findings for future research and for mental health counselors are discussed.Dissertation/Thesis
Masters Thesis Counseling 2017
47
Yi-ChenSung and 宋宜臻. "Effects of time delay asymmetry on two mutually coupled lasers." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/67rfdt.
Full text
48
Bin-KaiLiao and 廖彬凱. "Effects of injection strength asymmetry on two mutually coupled lasers." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/6e72e6.
Full textAbstract:
碩士國立成功大學
光電科學與工程學系
106
In this thesis, we present a numerical investigation of mutually injected semi-conductor lasers when the injection strength is asymmetric. For the purpose of ap-plications on communication system, the investigation focuses on period-one dy-namics and stable dynamics. First of all, the dynamics scenario of short delay sys-tem is studied to serve as a complete view of the dynamics changing. In order to study the effect on chip-scale mutually injected devices, we investigate the ul-tra-short delay system. Besides, the period-one dynamics is investigated in micro-wave fundamental frequency, sideband to carrier ratio and sideband rejection ratio and the potential of all-optical microwave generation is illustrated. Though symmet-ric mutual injection system is contract with unidirectional injection system, mutual injection systems share the same useful characteristic when proper asymmetry is presence. Finally, the stable dynamics is investigated in oscillation frequency and direct modulation response. The tunable high frequency oscillation and the condi-tions of flat frequency response is discovered.
49
Luo, Guo-Wei, and 羅國瑋. "A Study on Cross-Coupled Asymmetrical Bandpass Filter with Attenuation Pole." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/85029559105949462991.
Full textAbstract:
碩士國立臺灣海洋大學
電機工程學系
92
In the design of the cross-coupled asymmetrical bandpass filter with attenuation pole, the center frequency, the 3dB bandwidth, the insertion and return losses in the passband, and the frequency of attenuation pole in the stopband are the important parameters to be considered. In this thesis, the folded open-loop resonators are used to design the cross-coupled asymmetrical bandpass filters with attenuation poles. In this thesis, the design theory of the cross-coupled asymmetrical bandpass filter with attenuation pole is analyzed firstly. Next, the cross-coupled asymmetrical bandpass filters with an attenuation pole above and below the passband are designed and realized, respectively. Finally, the characteristics of these two filters are measured and compared with the simulation results.
50
Tu, Po-hsiang, and 涂博翔. "Development of Miniaturized Microwave Ring Coupler Using Asymmetrical T-structures and Dual Transmission Lines." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/d39u37.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
99
In this thesis, two guided-wave structures, namely “asymmetrical T-structures” and “dual transmission lines”, have been introduced, and then applied to realize compact planar ring couplers. Basically, this thesis consists of two main parts. The first part is using “asymmetrical T-structures” to design two miniaturized ring couplers. Two developed couplers only occupy 3.9 % and 4.48 % circuit sizes of the conventional structure, respectively. In addition, combining the reduce-length ring coupler and asymmetrical T-structures, the compact ring couplers can be realized with only 5.55 % circuit size of the conventional structure. The other part mainly uses dual transmission lines to implement “equal power” and “unequal power” ring couplers. The dual transmission line is composed of two parallel-connected high-impedance lines with unequal electrical lengths. By taking advantages of the circuit layout flexibility, the ring coupler realized by dual transmission lines can be optimally miniaturized. The ring coupler with equal power division only occupies 21.87 % circuit size of the conventional structure, and that with unequal power division only occupies 41.5 % circuit size.