A Comparative Study of Higher Order Bragg Gratings: Coupled-Mode Theory Versus Mode Expansion Modeling

H. Wenzel^a, R. Güther^a, A.M. Shams-Zadeh-Amiri^b, and P. Bienstman^c

^a Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
^b Photonami Corporation Richmond Hill, ON L4B 1E4, Canada
^c Department of Information Technology, Ghent University, Ghent 9000, Belgium.

Published in:
IEEE Journal of Quantum Electronics, vol. 42, no. 1, pp. 64-70, January 2006.
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Abstract:
The modal reflectivity and loss of lamellar diffraction gratings to be used in distributed-feedback and distributed-Bragg reflector lasers were computed in dependence of wavelength, duty cycle and Bragg order. Different methods based on the approximate coupled-mode theory and and the exact bidirectional mode expansion modeling were compared and a good mutual agreement was found. The slab Green’s function needed to compute the coupling coefficients can be approximated by that of a homogeneous unbounded medium with sufficient accuracy.

Index Terms:
Bragg grating, mode matching, radiation losses.

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