共查询到20条相似文献,搜索用时 0 毫秒
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Christos N. Capsalis Spyros N. Papadakis 《International Journal of Infrared and Millimeter Waves》1989,10(9):1089-1092
The evolution of an optical pulse in a single-mode, step index dielectric slab waveguide which is characterized by an intensity dependent dielectric function in the core and cladding regions is treated by means of differential equation techniques. A cubic order non-linearity is considered. The electromagnetic field distribution in the slab waveguide region satisfies a non-linear wave equation. This field can be represented in terms of even TE guided modes with a slowly varying envelope amplitude function.Then using the well known approximation, based on the slowly varying character of the amplitude function, a non linear partial differential equation is obtained for the amplitude function. As the coefficients of this equation depend on the distance across the transverse direction X, an averaging technique over x is applied to reduce the nonlinear partial differential equation into a form that is easily transformed to the so-called non-linear Scroedinger differential equation.This equation is then attacked by means of the well known Inverse Scattering method in the case of reflection less potentials. The single and double soliton solutions are obtained explicitly for a single-mode slab waveguide. Finally numerical results are presented in the time domain. 相似文献
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Kazuhiko Ogusu 《Optical and Quantum Electronics》1987,19(1):65-72
The propagation characteristics of TE waves guided by a film with a Kerr-like nonlinear permittivity are investigated theoretically. The dispersion equations for positive and negative nonlinear coefficients are derived by introducing the maximum field amplitude as a parameter for the nonlinearity. Typical numerical results for dispersion characteristics are shown. For a hollow waveguide with positive nonlinear coefficient, the threshold power flow is determined numericlly from the viewpoint of applications to optical power clipping. It is found that the threshold power flow is proportional to the square root of the unperturbed permittivity difference between the film, and cladding. 相似文献
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The electromagnetic-wave reflectivity of the surface of an insulating cubic-ferromagnet (ferrite) plate is calculated analytically and numerically with allowance for spin-wave damping. The frequency and magnetic-field dependences of the reflectivity are found at the orientational phase transition point and in the vicinity of this point for various values of the plate thickness. It is shown that the reflectivity exhibits anomalous behavior when the dynamic magnetic permeability becomes equal to the dielectric constant, as well as when dimensional resonances occur for electromagnetic or acoustic waves or ferromagnetic resonance takes place. At frequencies below the magnetoelastic gap in the quasi-spin-wave spectrum, the reflectivity may have anomalously low (down to zero) or anomalously high (up to unity) values. Such frequencies can lie in the microwave region. 相似文献
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V. A. Popov K. P. Cherkasova M. P. Kukhtin N. A. Khizhnyak 《Radiophysics and Quantum Electronics》1988,31(1):70-75
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 31, No. 1, pp. 86–92, January, 1988. 相似文献
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In this work we investigate the linear and nonlinear coupling properties of a novel multicore circular dielectric waveguide. The proposed device consists of a circular central core and many circular sectoral cores at the periphery, while the whole structure can be considered as a nonlinear multicore composite optical coupler. Hybrid guided modes in a circular sectoral dielectric waveguide are derived using circular harmonic expansion for the electromagnetic fields and the Point Matching Method (PMM) for the application of boundary conditions. Several cases are investigated varying some of the parameters of the geometry and the optical frequency in order to produce dispersion diagrams. In advance, the electric and magnetic field distributions for the fundamental guided modes are produced, while linear and nonlinear coupling coefficients as well as the sectoral waveguide mode effective area are derived. 相似文献
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Electromagnetic-wave excitation by a vertical electric dipole located inside a flat waveguide containing a vertical circular metal cylinder is examined. An exact solution is obtained, and the diffracted field inside the waveguide is analyzed. Algorithms are provided for electromagnetic-field calculation in a Rayleigh approximation and in a short-wave approximation. Results of numerical calculations of fields and directivity characteristics are presented. The effect of the cylinder on the radiation power of the dipole in the waveguide is analyzed.Nizhny Novgorod State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 11, pp. 965–976, November, 1993. 相似文献
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Manenkov A.B. Benson T.M. Kendall P.C. Sewell P.D. 《Optical and Quantum Electronics》2001,33(12):1195-1204
Scalar and vector theories are compared for weakly guided modes reflected from a planar optical dielectric waveguide end or laser facet. By utilizing the free space radiation mode method the range of validity of the scalar theory over a wide range of reflectivities is given explicitly for the first time. 相似文献
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Xu Shanjia Wu Xinzhang P. Greiner C. R. Becker R. Geick 《International Journal of Infrared and Millimeter Waves》1992,13(4):569-587
The microwave transmission and reflection is evaluated for stratified lossy dielectric segments partially filling the rectangular waveguide by the method which combines the multimode network theory with the rigorous mode matching procedure. As an example, we investigate in detail the microwave scattering properties of II-VI-epitaxial layer on a lossy dielectric substrate inserted in the rectangular waveguide. The experimental data verify the accuracy and the effectiveness of the present method. Extensive numerical results are presented to establish useful guidelines for the contactless microwave measurement of the conductivity of the epitaxial layer. 相似文献
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A. B. Manenkov 《Radiophysics and Quantum Electronics》1997,40(8):672-681
The problem of surface mode reflection from a break in a dielectric waveguide of arbitrary cross section is solved by a variational
method. The dependences of the reflection coefficient on the size and cross-sectional shape of the waveguide are examined.
Comparisons with results obtained by other methods, including the data calculated for the 2-D problem (a break in a dielectric
plate), are presented.
P. L. Kapitsa Institute of Physical Problems, Russian Academy of Sciences, Moscow, Russia. Translated from Izvestiya Vysshikh
Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 8, pp. 1004–1018, August, 1997. 相似文献
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A novel asymmetric Bragg reflection waveguide (BRW) showing anomalous dispersion characteristic is presented. The abnormal behaviour of increase of modal effective index with wavelength is primarily caused by the changes taking place in the imaginary part of the Bloch wavevector, in the periodic stratified cladding. The phase velocity and the group velocity dispersion characteristics for the waveguide have also been analyzed. Such an anomalous behaviour can find applications in the design of integrated optical devices. 相似文献
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Group delay for a reflected light pulse from a weakly absorbing dielectric slab is theoretically investigated, and large negative group delay is found for weak absorption near a resonance of the slab [Re(kd)=mpi]. The group delay for both the reflected and transmitted pulses will be saturated with an increase of the absorption. 相似文献