Fast algorithms for electrically large objects buried in layered media are mainly hindered by two... more Fast algorithms for electrically large objects buried in layered media are mainly hindered by two time-consuming processes. One is the table filling of Green's function, and the other is the solving of the impedance matrix equation. For the first, to accelerate the evaluation of the time-consuming Sommerfeld integral in the dyadic Green's function (DGF), the discrete complex image method (DCIM) is introduced to get a closed-form DGF. To further accelerate the calculation of DGF for the volume electric field integral equation (EFIE), DGF is split before applying DCIM. For the second, the iterative solver stabilized biconjugate gradient fast Fourier transform (BCGS-FFT) is combined with DCIM for solving the matrix equations. Meanwhile, the closed-form DGF enables the "spherical-mean" Green's function, which eliminates the singularity of Green's function. Numerical results show that the weaker singularity results in a faster and steadier convergence rate for iterative solvers
In this paper, a confinement loss diagram (CLD) is proposed as a novel design tool for Bragg fibe... more In this paper, a confinement loss diagram (CLD) is proposed as a novel design tool for Bragg fibers. The CLD is a 2-D pseudocolor diagram, which presents the loss properties of a Bragg fiber in a coordinate of normalized frequency and the effective refractive index (ωr, neff), to quantitatively characterize the Bragg cladding without the parameters of the core. The CLD is derived from a ray reflection model, which describes the propagation in Bragg fibers as reflection and ray trajectory. Confinement loss is first determined from the reflection process and then developed into a 2-D CLD. In this paper, the confinement loss calculation with the ray reflection model is first shown to be accurate for Bragg fibers with a core radius as small as 0.8 wavelength, both in the TE modes and the TM modes. Then, the CLD is exploited to characterize the level core Bragg fiber and the depressed core Bragg fiber. It is found that the level core fiber is suitable for wide band designs, while the depressed core fiber is good for narrow band designs. Lastly, the CLD is applied to characterize the loss properties of different order bandgaps, so that the propagation region can be located for optimum Bragg fiber design.
In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is pro... more In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is proposed and applied to the design of zero-dispersion fibers and ultrawideband dispersion-flattened fibers. The proposed method can predict the dispersion of MSFs accurately by taking secondary dispersion into account, this being the interactive contribution from both the material and the geometrical effects. The secondary dispersion is modeled as a function of the propagation index difference and wavelength, and the model can be exploited to predict the secondary dispersion of scaled structures. This method of predicting dispersion is then combined with the scalable property of the geometrical dispersion to form a scalable dispersion-tailoring approach. This new design approach is applied to the design of zero-dispersion MSFs working at 1.55 m and 1.3 m, respectively. It is then shown that the method can be used for the design of ultrawideband zero-dispersion fibers. A MSF with predicted dispersion as low as 0.2 ps/(kmnm) over the range 1.3-1.6 m is described.
In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is pro... more In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is proposed and applied to the design of zero-dispersion fibers and ultrawideband dispersion-flattened fibers. The proposed method can predict the dispersion of MSFs accurately by taking secondary dispersion into account, this being the interactive contribution from both the material and the geometrical effects. The secondary dispersion is modeled as a function of the propagation index difference and wavelength, and the model can be exploited to predict the secondary dispersion of scaled structures. This method of predicting dispersion is then combined with the scalable property of the geometrical dispersion to form a scalable dispersion-tailoring approach. This new design approach is applied to the design of zero-dispersion MSFs working at 1.55 m and 1.3 m, respectively. It is then shown that the method can be used for the design of ultrawideband zero-dispersion fibers. A MSF with predicted dispersion as low as 0.2 ps/(kmnm) over the range 1.3-1.6 m is described.
Page 1. Progress In Electromagnetics Research, PIER 80, 161178, 2008 AUTOMATIC INCORPORATION OF ... more Page 1. Progress In Electromagnetics Research, PIER 80, 161178, 2008 AUTOMATIC INCORPORATION OF SURFACE WAVE POLES IN DISCRETE COMPLEX IMAGE METHOD L. Zhuang School of Electronic Information Wuhan University Wuhan 430079, China ...
Fast algorithms for electrically large objects buried in layered media are mainly hindered by two... more Fast algorithms for electrically large objects buried in layered media are mainly hindered by two time-consuming processes. One is the table filling of Green's function, and the other is the solving of the impedance matrix equation. For the first, to accelerate the evaluation of the time-consuming Sommerfeld integral in the dyadic Green's function (DGF), the discrete complex image method (DCIM) is introduced to get a closed-form DGF. To further accelerate the calculation of DGF for the volume electric field integral equation (EFIE), DGF is split before applying DCIM. For the second, the iterative solver stabilized biconjugate gradient fast Fourier transform (BCGS-FFT) is combined with DCIM for solving the matrix equations. Meanwhile, the closed-form DGF enables the "spherical-mean" Green's function, which eliminates the singularity of Green's function. Numerical results show that the weaker singularity results in a faster and steadier convergence rate for iterative solvers
In this paper, a confinement loss diagram (CLD) is proposed as a novel design tool for Bragg fibe... more In this paper, a confinement loss diagram (CLD) is proposed as a novel design tool for Bragg fibers. The CLD is a 2-D pseudocolor diagram, which presents the loss properties of a Bragg fiber in a coordinate of normalized frequency and the effective refractive index (ωr, neff), to quantitatively characterize the Bragg cladding without the parameters of the core. The CLD is derived from a ray reflection model, which describes the propagation in Bragg fibers as reflection and ray trajectory. Confinement loss is first determined from the reflection process and then developed into a 2-D CLD. In this paper, the confinement loss calculation with the ray reflection model is first shown to be accurate for Bragg fibers with a core radius as small as 0.8 wavelength, both in the TE modes and the TM modes. Then, the CLD is exploited to characterize the level core Bragg fiber and the depressed core Bragg fiber. It is found that the level core fiber is suitable for wide band designs, while the depressed core fiber is good for narrow band designs. Lastly, the CLD is applied to characterize the loss properties of different order bandgaps, so that the propagation region can be located for optimum Bragg fiber design.
In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is pro... more In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is proposed and applied to the design of zero-dispersion fibers and ultrawideband dispersion-flattened fibers. The proposed method can predict the dispersion of MSFs accurately by taking secondary dispersion into account, this being the interactive contribution from both the material and the geometrical effects. The secondary dispersion is modeled as a function of the propagation index difference and wavelength, and the model can be exploited to predict the secondary dispersion of scaled structures. This method of predicting dispersion is then combined with the scalable property of the geometrical dispersion to form a scalable dispersion-tailoring approach. This new design approach is applied to the design of zero-dispersion MSFs working at 1.55 m and 1.3 m, respectively. It is then shown that the method can be used for the design of ultrawideband zero-dispersion fibers. A MSF with predicted dispersion as low as 0.2 ps/(kmnm) over the range 1.3-1.6 m is described.
In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is pro... more In this paper, a scalable dispersion management approach for microstructured fibers (MSFs) is proposed and applied to the design of zero-dispersion fibers and ultrawideband dispersion-flattened fibers. The proposed method can predict the dispersion of MSFs accurately by taking secondary dispersion into account, this being the interactive contribution from both the material and the geometrical effects. The secondary dispersion is modeled as a function of the propagation index difference and wavelength, and the model can be exploited to predict the secondary dispersion of scaled structures. This method of predicting dispersion is then combined with the scalable property of the geometrical dispersion to form a scalable dispersion-tailoring approach. This new design approach is applied to the design of zero-dispersion MSFs working at 1.55 m and 1.3 m, respectively. It is then shown that the method can be used for the design of ultrawideband zero-dispersion fibers. A MSF with predicted dispersion as low as 0.2 ps/(kmnm) over the range 1.3-1.6 m is described.
Page 1. Progress In Electromagnetics Research, PIER 80, 161178, 2008 AUTOMATIC INCORPORATION OF ... more Page 1. Progress In Electromagnetics Research, PIER 80, 161178, 2008 AUTOMATIC INCORPORATION OF SURFACE WAVE POLES IN DISCRETE COMPLEX IMAGE METHOD L. Zhuang School of Electronic Information Wuhan University Wuhan 430079, China ...
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