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de Sterke CM

Publications and source records attributed to de Sterke CM.

16 recordsLinked to original sources
PubMed2000

Corrections to coupled mode theory for deep gratings

We generalize the standard coupled mode equations describing interactions between forward and backward propagating waves in a nonlinear optical Bragg grating. Including the lowest order corrections of the grating depth, we obtain a Hamiltonian system that can be regarded as an extension of the usual coupled mode equations for shallow gratings. The results are consistent with existing results based on a Bloch wave expansion. We also obtain exact traveling solitary wave solutions, that can be regarded as a generalized gap soliton, modified by the grating's depth.

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PubMed2000

Propagation of nonlinear pulses in chirped fiber gratings

The propagation of nonlinear optical pulses in chirped fiber gratings is studied. The dynamics is analyzed on the basis of the inhomogeneous nonlinear Schrodinger equation. By using perturbation theory we demonstrate that the inhomogeneity affects the amplitude and the width, as well as the phase and the velocity of the soliton. The dynamics of a multisoliton pulse (breather) in chirped gratings is also discussed. It is shown that the velocity variation of individual solitons leads to the breaking of a bound multisoliton state. This process manifests itself as the pulse splitting that is experimentally observed by other authors. Numerical simulations of the pulse dynamics agree well with analytical results for wide range of parameters.

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PubMed2000

Gap solitons in quadratically nonlinear gratings: beyond the cascading limit

We consider pulse propagation in quadratically nonlinear gratings. Assuming that the phase mismatch between the fundamental and the second-harmonic frequencies deltak is large, we present a perturbation method in deltak(-1). In the well known cascading limit, terms to deltak(-1) are kept; here we keep terms to deltak(-2), which leads to another type of coupled mode equations. Numerical calculation of the full equations support our theoretical results.

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