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Papers by Karlheinz Ramm

Research paper thumbnail of Comparison of a Vectorial and New Semivectorial Finite Difference Approach for Optical Waveguides

In this article, a new semivectorial finite difference method is presented. By comparing the resu... more In this article, a new semivectorial finite difference method is presented. By comparing the results obtained by the new approach with a vectorial method, it is shown that the accuracy is still very high with costs reduced by a factor of two.

Research paper thumbnail of Das Eigenwertproblem laengshomogener dielektrischer Wellenleiter

Theory and construction of a multigrid program for the numerical solution of the eigenvalue probl... more Theory and construction of a multigrid program for the numerical solution of the eigenvalue problem for isotropic optical waveguides. (Master's Thesis, TU Braunschweig,
1993)

Research paper thumbnail of Ein Mehrgitterprogramm zur Losung des Eigenwertproblems fur ein elliptisches System verkoppelter Di

Ramm, K., P. Lüsse, and P. Stuwe. "Ein Mehrgitterprogramm zur Loesung des Eigenwertproblems fuer ein elliptisches System verkoppelter Differentialgleichungen." ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK 75 (1995): S701-S701.

Ein Mehrgitterprogramm zur Losung des Eigenwertproblems fur ein elliptisches System verkoppelt... more Ein Mehrgitterprogramm zur Losung des Eigenwertproblems
fur ein elliptisches System verkoppelter Di erentialgleichungen

Research paper thumbnail of Vectorial eigenmode calculation for anisotropic planar optical waveguides

Lüsse, P., K. Ramm, and H-G. Unger. "Vectorial eigenmode calculation for anisotropic planar optical waveguides." Electronics Letters 32.1 (1996): 38-39.

A newly derived spurious-mode-free finite-difference-method for computing the eigenmodes of aniso... more A newly derived spurious-mode-free finite-difference-method for computing the eigenmodes of anisotropic planar optical waveguides is presented. For solving the linear eigensystem, a powerful multi-grid-method is used. An application of the method is given.

Research paper thumbnail of Multigrid eigenvalue solver for mode calculation of planar optical waveguides.

Ramm, K., P. Lusse, and H. G. Unger. "Multigrid eigenvalue solver for mode calculation of planar optical waveguides." Photonics Technology Letters, IEEE 9.7 (1997): 967-969.

We present a multigrid algorithm suited to solve the discretized eigenvalue problem resulting fro... more We present a multigrid algorithm suited to solve the discretized eigenvalue problem resulting from Maxwell's equations in the case of a planar optical waveguide homogeneous in one coordinate direction. The discretization scheme provides a full-vector solution for lossy or anisotropic media. It is possible to calculate higher order eigenmodes. The multigrid algorithm turns out to be a very powerful tool to find the solution in a short time with a moderate need of storage capacity even for very fine discretizations. This is demonstrated for the case of a rib waveguide.

Research paper thumbnail of Comparison of a vectorial and new semivectorial finite-difference approach for optical waveguides

Lu, P., Ramm, K., Unger, H. G., & Schu, J. (1997). Comparison of a vectorial and new semivectorial finite-difference approach for optical waveguides. Optical and Quantum Electronics, 29(2), 115-120.

In this article, a new semivectorial finite-difference method is presented. By comparing the resu... more In this article, a new semivectorial finite-difference method is presented. By comparing the results obtained by the new approach with a vectorial method, it is shown that the accuracy is still very high with costs reduced by a factor of two.

Research paper thumbnail of Vektorielle FD-Berechnungsverfahren fuer optische Wellenleiterbauelemente mit anisotropen Materialeigenschaften

Luesse, P., K. Ramm, and H. G. Unger. "Vektorielle FD-Berechnungsverfahren fuer optische Wellenleiterbauelemente mit anisotropen Materialeigenschaften." Kleinheubacher Berichte (1996): 163-170.

Thesis Chapters by Karlheinz Ramm

Research paper thumbnail of Diplomarbeit original.pdf

Ein Mehrgitterprogramm zur Berechnung des transversalen magnetischen Feldes der Grundwelle längsh... more Ein Mehrgitterprogramm zur Berechnung des transversalen magnetischen Feldes der Grundwelle längshomogener dielektrischer Wellenleiter sowie des zugehörigen Ausbreitungskoeffizienten.

Research paper thumbnail of Comparison of a Vectorial and New Semivectorial Finite Difference Approach for Optical Waveguides

In this article, a new semivectorial finite difference method is presented. By comparing the resu... more In this article, a new semivectorial finite difference method is presented. By comparing the results obtained by the new approach with a vectorial method, it is shown that the accuracy is still very high with costs reduced by a factor of two.

Research paper thumbnail of Das Eigenwertproblem laengshomogener dielektrischer Wellenleiter

Theory and construction of a multigrid program for the numerical solution of the eigenvalue probl... more Theory and construction of a multigrid program for the numerical solution of the eigenvalue problem for isotropic optical waveguides. (Master's Thesis, TU Braunschweig,
1993)

Research paper thumbnail of Ein Mehrgitterprogramm zur Losung des Eigenwertproblems fur ein elliptisches System verkoppelter Di

Ramm, K., P. Lüsse, and P. Stuwe. "Ein Mehrgitterprogramm zur Loesung des Eigenwertproblems fuer ein elliptisches System verkoppelter Differentialgleichungen." ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK 75 (1995): S701-S701.

Ein Mehrgitterprogramm zur Losung des Eigenwertproblems fur ein elliptisches System verkoppelt... more Ein Mehrgitterprogramm zur Losung des Eigenwertproblems
fur ein elliptisches System verkoppelter Di erentialgleichungen

Research paper thumbnail of Vectorial eigenmode calculation for anisotropic planar optical waveguides

Lüsse, P., K. Ramm, and H-G. Unger. "Vectorial eigenmode calculation for anisotropic planar optical waveguides." Electronics Letters 32.1 (1996): 38-39.

A newly derived spurious-mode-free finite-difference-method for computing the eigenmodes of aniso... more A newly derived spurious-mode-free finite-difference-method for computing the eigenmodes of anisotropic planar optical waveguides is presented. For solving the linear eigensystem, a powerful multi-grid-method is used. An application of the method is given.

Research paper thumbnail of Multigrid eigenvalue solver for mode calculation of planar optical waveguides.

Ramm, K., P. Lusse, and H. G. Unger. "Multigrid eigenvalue solver for mode calculation of planar optical waveguides." Photonics Technology Letters, IEEE 9.7 (1997): 967-969.

We present a multigrid algorithm suited to solve the discretized eigenvalue problem resulting fro... more We present a multigrid algorithm suited to solve the discretized eigenvalue problem resulting from Maxwell's equations in the case of a planar optical waveguide homogeneous in one coordinate direction. The discretization scheme provides a full-vector solution for lossy or anisotropic media. It is possible to calculate higher order eigenmodes. The multigrid algorithm turns out to be a very powerful tool to find the solution in a short time with a moderate need of storage capacity even for very fine discretizations. This is demonstrated for the case of a rib waveguide.

Research paper thumbnail of Comparison of a vectorial and new semivectorial finite-difference approach for optical waveguides

Lu, P., Ramm, K., Unger, H. G., & Schu, J. (1997). Comparison of a vectorial and new semivectorial finite-difference approach for optical waveguides. Optical and Quantum Electronics, 29(2), 115-120.

In this article, a new semivectorial finite-difference method is presented. By comparing the resu... more In this article, a new semivectorial finite-difference method is presented. By comparing the results obtained by the new approach with a vectorial method, it is shown that the accuracy is still very high with costs reduced by a factor of two.

Research paper thumbnail of Vektorielle FD-Berechnungsverfahren fuer optische Wellenleiterbauelemente mit anisotropen Materialeigenschaften

Luesse, P., K. Ramm, and H. G. Unger. "Vektorielle FD-Berechnungsverfahren fuer optische Wellenleiterbauelemente mit anisotropen Materialeigenschaften." Kleinheubacher Berichte (1996): 163-170.

Research paper thumbnail of Diplomarbeit original.pdf

Ein Mehrgitterprogramm zur Berechnung des transversalen magnetischen Feldes der Grundwelle längsh... more Ein Mehrgitterprogramm zur Berechnung des transversalen magnetischen Feldes der Grundwelle längshomogener dielektrischer Wellenleiter sowie des zugehörigen Ausbreitungskoeffizienten.