scholarly journals A simple analytical model for confinement loss estimation in hollow-core Tube Lattice Fibers

2019 ◽  
Vol 27 (4) ◽  
pp. 5230 ◽  
Author(s):  
Luca Vincetti ◽  
Lorenzo Rosa
Fibers ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 58
Author(s):  
Lorenzo Rosa ◽  
Federico Melli ◽  
Luca Vincetti

In this work, we propose analytical formulas for the estimation of dispersion properties and effective area of the fundamental mode of hollow-core inhibited coupling fibers with a microstructured cladding composed by a ring of dielectric tubes. The formulas are based on a model which has already been successfully applied to the estimation of confinement loss. The model takes into account the effects of the coupling of the fundamental core mode with the cladding modes in the context of the single-tube approximation. Effective index, group velocity dispersion, and effective area of the fundamental mode are estimated and compared with the results obtained from numerical simulations, by considering ten different fibers. The comparison shows a good accuracy of the proposed formulas, which do not require any tuning of fitting parameters. On the basis of the analysis carried out, a scaling law relating the effective area to the core radius is also given. Finally, the formulas give a good estimation of the same parameters of other Hollow-core inhibited coupling fibers, such as nested, ice-cream, and kagome fibers.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 420
Author(s):  
Ang Deng ◽  
Wonkeun Chang

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.


Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 284
Author(s):  
Bowei Wan ◽  
Lianqing Zhu ◽  
Xin Ma ◽  
Tianshu Li ◽  
Jian Zhang

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.


1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.


2008 ◽  
Vol 85 (4) ◽  
pp. 228-242 ◽  
Author(s):  
Hongfang Zhang ◽  
Charles A. Garris

2018 ◽  
Vol 192 ◽  
pp. 366-380 ◽  
Author(s):  
Subhan Ahmad ◽  
Pradeep Bhargava ◽  
Ajay Chourasia

2017 ◽  
Vol 65 (02) ◽  
pp. 443-455
Author(s):  
NORIMICHI MATSUEDA ◽  
JUN’ICHI MIKI

We first report three empirical findings from our survey on the contracting-out of municipal waste collection services in Japan: (1) the rate of contracting-out and the contract price are inversely related, (2) this inverse relationship tapers out as the contracting rate becomes sufficiently high, and the contract price even tends to go up as the contracting rate approaches 100% and (3) there is a significant disparity in the contracting rates between the eastern and western parts of Japan. In order to account for these observations, we then set up a simple analytical model and examine its implications. Also, we discuss the issues that a potential hold-up situation could give rise to when the services are completely contracted out to private firms.


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