scholarly journals Phase Dislocations in Hollow Core Waveguides

Fibers ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 59
Author(s):  
Andrey Pryamikov
Keyword(s):  
Electric Fields ◽  
Rotational Symmetry ◽  
Vortex Formation ◽  
Hollow Core ◽  
Core Mode ◽  
Field Phase ◽  
The Core ◽  
Light Localization ◽  
Air Core ◽  
Basic Concepts

This paper discusses the basic concepts of phase dislocations and vortex formation in the electric fields of fundamental air core mode of hollow core waveguides with specific types of rotational symmetry of the core‐cladding boundary. Analysis of the behavior of the electric field phase in the transmission bands shows that the mechanism of light localization in the hollow core waveguides with discrete rotational symmetry of the core-cladding boundary cannot be completely described by the ARROW model. For an accurate description of the phase behavior, it is necessary to account for phase jumps of the magnitude of π when passing through the phase dislocations.

Study of Birefringence and Mode Field for Hollow-Core Photonic Bandgap Fiber

2014 ◽  
Vol 609-610 ◽  
pp. 324-329
Author(s):  
Li Shuang Feng ◽  
Wen Shuai Song ◽  
Xiao Yuan Ren
Keyword(s):  
Field Distribution ◽  
Photonic Bandgap ◽  
Surface Mode ◽  
Hollow Core ◽  
The Finite Element Method ◽  
Core Mode ◽  
Photonic Bandgap Fiber ◽  
Mode Field ◽  
Air Core ◽  
Polarization Maintaining

Since the Appearance of Hollow-Core Photonic Bandgap Fiber (HC-PBF), it was Widely Concerned for its Excellent Characteristics. in Order to Study the Characteristics of the HC-PBF that can be Used in Resonator Fiber Optic Gyros (R-Fogs), the Model Structure of a Polarization-Maintaining HC-PBF was Built and its Performance was Simulated by Using the Finite Element Method (FEM). its Mode Field Distribution and Birefringence Characteristics were Obtained. the Influences of the Air Core and Cladding Structures on the Mode Field Distribution and Birefringence were Simulated and Analyzed Further. the Result Showed that there are both Core Mode and Surface Mode in the Structure we Built. by Adding Scattering Points into the Fiber Core, the Surface Mode can be Significantly Suppressed. by Matching the Size of Core and Air Holes around the Core, a Birefringence up to 8*10-4 were Obtained.

scholarly journals Geometrical Scaling of Antiresonant Hollow-Core Fibers for Mid-Infrared Beam Delivery

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang
Keyword(s):  
Structural Parameters ◽  
Transmission Band ◽  
Confinement Loss ◽  
Hollow Core ◽  
Core Size ◽  
Core Diameter ◽  
Mid Infrared ◽  
The Core ◽  
Tubular Type ◽  
Beam Delivery

We numerically investigate the effect of scaling two key structural parameters in antiresonant hollow-core fibers—dielectric wall thickness of the cladding elements and core size—in view of low-loss mid-infrared beam delivery. We demonstrate that there exists an additional resonance-like loss peak in the long-wavelength limit of the first transmission band in antiresonant hollow-core fibers. We also find that the confinement loss in tubular-type hollow-core fibers depends strongly on the core size, where the degree of the dependence varies with the cladding tube size. The loss scales with the core diameter to the power of approximately −5.4 for commonly used tubular-type hollow-core fiber designs.

scholarly journals Characteristic Analysis and Structural Design of Hollow-Core Photonic Crystal Fibers with Band Gap Cladding Structures

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 284
Author(s):  
Bowei Wan ◽  
Lianqing Zhu ◽  
Xin Ma ◽  
Tianshu Li ◽  
Jian Zhang
Keyword(s):  
Photonic Crystal ◽  
Band Gap ◽  
Photonic Crystal Fibers ◽  
Relative Sensitivity ◽  
Confinement Loss ◽  
Hollow Core ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
The Core ◽  
Crystal Fibers

Due to their flexible structure and excellent optical characteristics hollow-core photonic crystal fibers (HC-PCFs) are used in many fields, such as active optical devices, communications, and optical fiber sensing. In this paper, to analyze the characteristics of HC-PCFs, we carried out finite element analysis and analyzed the design for the band gap cladding structure of HC-PCFs. First, the characteristics of HC19-1550 and HC-1550-02 in the C-band were simulated. Subsequently, the structural optimization of the seven-cell HC-1550-02 and variations in characteristics of the optimized HC-1550-02 in the wavelength range 1250–1850 nm were investigated. The simulation results revealed that the optimal number of cladding layers is eight, the optimal core radius is 1.8 times the spacing of adjacent air holes, and the optimal-relative thickness of the core quartz-ring is 2.0. In addition, the low confinement loss bandwidth of the optimized structure is 225 nm. Under the transmission bandwidth of the optimized structure, the core optical power is above 98%, the confinement loss is below 9.0 × 10−3 dB/m, the variation range of the effective mode field area does not exceed 10 μm2, and the relative sensitivity is above 0.9570. The designed sensor exhibits an ultra-high relative sensitivity and almost zero confinement loss, making it highly suitable for high-sensitivity gas or liquid sensing.

scholarly journals Control of Excitation of Cladding Modes by Tapering an Insertion of Special Fiber

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2498
Author(s):  
Diomid D. Bakurov ◽  
Oleg V. Ivanov
Keyword(s):  
Field Distribution ◽  
Refractive Indices ◽  
Coupling Coefficients ◽  
Core Mode ◽  
Transmission Characteristics ◽  
Tapered Fiber ◽  
Fiber Core ◽  
The Core

A method for controlling the excitation of cladding modes by tapering special fiber insertions made of SM450 and coreless fibers is proposed. The coupling coefficients between the core mode and the cladding modes of the tapered fiber insertion are calculated. For the calculation, changes in the effective refractive indices and phases of the fiber core and in the cladding modes upon tapering are found. The field distribution of the core mode of the standard fiber transmitted through fiber insertion is obtained. The transmission characteristics of insertions of SM450 and coreless fibers during tapering are simulated and compared with the experiment. The possibility of controlling the transmission and excitation of various cladding modes is confirmed experimentally.

scholarly journals Low-loss ARROW waveguide with rectangular hollow core and rectangular low-density polyethylene/air reflectors for terahertz waves

2018 ◽  
Vol 27 (03) ◽  
pp. 1850029 ◽  
Author(s):  
Henri P. Uranus ◽  
B. M. A. Rahman
Keyword(s):  
Refractive Index ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Hollow Core ◽  
Terahertz Waves ◽  
Low Loss ◽  
Leakage Loss ◽  
Crystal Fiber ◽  
Air Core ◽  
The Waves

Designing low-loss waveguides for terahertz waves is challenging as most materials are very lossy in this frequency band. Most scientists simply consider transmitting the waves through low-loss air, which however also has its own difficulties as index-guiding is not possible. In this paper, we report on the design of low-loss waveguides for terahertz waves and associated results by using a finite element leaky mode solver. These results show that waveguides designed using ARROW (anti-resonant reflecting optical waveguide) approach yield a low combined absorption and leakage loss down to only 0.05[Formula: see text]dB/cm for the q-TE[Formula: see text] fundamental mode using realistic values of refractive index at 1 THz operating frequency. The structure employs rectangular hollow-core and low-density polyethylene/air anti-resonant reflecting bilayers, which can be easily fabricated. These results are compared with those of other structures, i.e., a photonic crystal fiber-like structures using the same materials with rectangular holes, which is shown to give a higher loss of 3[Formula: see text]dB/cm and a suspended air-core waveguide with TOPAS vein offering a loss of 1[Formula: see text]dB/cm.

scholarly journals «Rýhanı dúnıetanym», «rýhanılyq» kategorııalarynyń pedagogıkalyq jáne psıhologııalyq uǵymdary [Pedagogical and Psychological Concepts of the Category “Spiritual Worldview” and “Spirituality”]

2020 ◽  
Vol 3 (117) ◽  
pp. 161-174
Author(s):  
B.J. Parıdınova ◽  
Keyword(s):  
Social Structure ◽  
Research Problem ◽  
The State ◽  
Theoretical Understanding ◽  
The Core ◽  
The Social ◽  
Spirituality In Education ◽  
Basic Concepts ◽  
The Individual ◽  
Pedagogical Science

The problem of developing the spiritual worldview and spirituality was the development of society at all stages. The spiritual worldview and spirituality of the individual, teachers in society changed depending on the level of the social structure of the state and its ideology, religious and secular views, the development of pedagogical science. Therefore, the spiritual worldview and spirituality of the whole society is one of the most important characteristics of the pedagogical preparation of the individual. The research problem is relevant in the framework of the program «Rukhani zhangyru». Therefore, we believe that a set of activities under the program is the core of this topic. Spiritual worldview and spirituality is the most important issue in the context of globalization. The purpose of this article is to generalize and systematize this problem, to determine the role and place of the spiritual worldview and spirituality. To achieve the purpose, this study discusses some of the findings of scientists on the problem of spiritual worldview and spirituality in education. The discussed fundamental principles of development and existing scientific works on the problem of spiritual worldview and spirituality. Many actual issues can be considered in the notion of concept since these categories has not yet been studied in science. In this article special attention is paid to spiritual worldview and spirituality and its basic concepts, which is one of the most important problems in pedagogy and psychology. The article the relevance and importance of theoretical understanding of the data category. Presented some theoretical problems of the formation and preservation of spiritual worldview and spirituality. Рухани дүниетанымның даму мәселесі және руханилық қоғам дамуының барлық салаларында өзекті болып саналады. Қоғамдағы тұлғаның, мұғалімнің рухани дүниетанымы мен руханилығы мемлекеттің әлеуметтік құрылысы мен оның идеологиясы, діни және зайырлы көзқарастары, педагогикалық ғылымның дамуы деңгейіне байланысты өзгеріп отырады. Сондықтан барлық қоғам мүшелерінің рухани дүниетанымы мен руханилығы тұлғаның педагогикалық дайындығының маңызды сипаттамалық белгісі болып табылады. Зерттеу мәселесі «Рухани жаңғыру» бағдарламасы аясында өзекті болып саналады. Сол себепті бағдарлама шеңберіндегі шаралар кешені берілген тақырыптың өзегі деп ойлаймыз. Жаһандану шарттарында «Рухани дүниетаным» және «Руханилық» категориялары маңызды мәселе болып табылады. Осы мақаланың мақсаты болып берілген мәселені жинақтау және жүйелеу, рухани дүниетаным мен руханилықтың рөлін, орнын анықтау болып саналады. Мақсатқа жету үшін берілген жұмыста білім берудегі рухани дүниетаным мен руханилық мәселесіне байланысты кейбір қорытындылары қарастырылады. Рухани дүниетаным мен руханилық мәселесіне байланысты дамытудың негізгі қағидалары мен ғылымда бар жұмыстар талқыланады. Өйткені берілген категориялар ғылымда толықтай зерттелмеген және зерттелуі тиіс көптеген өзекті мәселелері жетерлік. Берілген мақалада рухани дүниетаным және руханилықтың, оның педагогикадағы және психологиядағы негізгі түсініктеріне ерекше назар аударылады. Мақалада берілген категорияларды теориялық түсінудің өзектілігі мен маңыздылығы дәйектеледі. Рухани дүниетаным мен руханилықтың қалыптасуы мен сақтаудағы кейбір теориялық мәселелері ұсынылған.

scholarly journals Basic concepts of depression

2008 ◽  
Vol 10 (3) ◽  
pp. 279-289 ◽  
Keyword(s):  
Bipolar Disorder ◽  
Affective Disorders ◽  
Life Stress ◽  
Endogenous Depression ◽  
Modern Concept ◽  
Reactive Depression ◽  
The Core ◽  
Broad Concept ◽  
Basic Concepts ◽  
The 1960S

This paper reviews concepts of depression, including history and classification. The original broad concept of melancholia included all forms of quiet insanity. The term depression began to appear in the nineteenth century, as did the modern concept of affective disorders, with the core disturbance now viewed as one of mood. The 1980s saw the introduction of defined criteria into official diagnostic schemes. The modern separation into unipolar and bipolar disorder was introduced following empirical research by Angst and Perris in the 1960s. The partially overlapping distinctions between psychotic and neurotic depression, and between endogenous and reactive depression, started to generate debate in the 1920s, with considerable multivariate research in the 1960s. The symptom element in endogenous depression currently survives in melancholia or somatic syndrome. Life stress is common in various depressive pictures. Dysthymia, a valuable diagnosis, represents a form of what was regarded earlier as neurotic depression. Other subtypes are also discussed.

scholarly journals Hollow core optical fibres with comparable attenuation to silica fibres between 600 and 1100 nm

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hesham Sakr ◽  
Yong Chen ◽  
Gregory T. Jasion ◽  
Thomas D. Bradley ◽  
John R. Hayes ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Density Fluctuations ◽  
Power Delivery ◽  
Optical Data ◽  
Optical Fibres ◽  
Hollow Core ◽  
Quantum Communications ◽  
Scattering Loss ◽  
Air Core ◽  
Solid Glass

AbstractFor over 50 years, pure or doped silica glass optical fibres have been an unrivalled platform for the transmission of laser light and optical data at wavelengths from the visible to the near infra-red. Rayleigh scattering, arising from frozen-in density fluctuations in the glass, fundamentally limits the minimum attenuation of these fibres and hence restricts their application, especially at shorter wavelengths. Guiding light in hollow (air) core fibres offers a potential way to overcome this insurmountable attenuation limit set by the glass’s scattering, but requires reduction of all the other loss-inducing mechanisms. Here we report hollow core fibres, of nested antiresonant design, with losses comparable or lower than achievable in solid glass fibres around technologically relevant wavelengths of 660, 850, and 1060 nm. Their lower than Rayleigh scattering loss in an air-guiding structure offers the potential for advances in quantum communications, data transmission, and laser power delivery.

The Discussion of the Concept of Sustainable Development of Ecological Architectural Aesthetics

2012 ◽  
Vol 598 ◽  
pp. 8-11
Author(s):  
Shen Qi Gan ◽  
Hong Zhang
Keyword(s):  
Sustainable Development ◽  
Aesthetic Theory ◽  
Aesthetic Value ◽  
The Core ◽  
Natural Beauty ◽  
Man And Nature ◽  
Environment Perception ◽  
Basic Concepts ◽  
Ecological Architecture ◽  
The Aesthetic

This paper introduces the basic concepts of ecological aesthetic, pointing out that the ecological aesthetic comes from population, resources, environment and other factors, understanding the natural beauty from the harmonious compatibility between man and nature, the environment, perception, greatly improving the aesthetic value of taste. This paper introduces the core categories、aesthetic standards and the three characteristics of ecological architectural aesthetics in detail, interpret the ecological architecture and its aesthetic theory.

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