We propose a design for light coupling optimization between an optical fiber and a sub-micrometer waveguide using a subwavelength segmented waveguide taper with subwavelength periodicity. The power coupling and light ...
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ISBN:
(数字)9781510611665
ISBN:
(纸本)9781510611665;9781510611658
We propose a design for light coupling optimization between an optical fiber and a sub-micrometer waveguide using a subwavelength segmented waveguide taper with subwavelength periodicity. The power coupling and light coupling of the output waveguide are calculated, optimized and compared with other designs and values found in the literature. The optimized tapers has been successfully and efficient designed using evolutionary algorithms based on artificial immune system (AIS), the genetic algorithm (GA) and ant colony optimization (ACO). Power coupling above 75 % have been obtained with the evolutionary algorithms.
A numerical analysis of periodic segmented waveguides (PSWs) using the 2-D finite element method (2D-FEM) in the frequency domain is presented. This method has significantly lower computational cost when compared with...
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A numerical analysis of periodic segmented waveguides (PSWs) using the 2-D finite element method (2D-FEM) in the frequency domain is presented. This method has significantly lower computational cost when compared with 3-D methods that have been used to model PSWs, and can also model back reflected signals. Unlike photonic crystal waveguides, light confinement in a PSW is due to total internal reflection as in a continuous waveguide (CWG). We show that the dispersion relation of the guided modes in PSW is strongly influenced by the dielectric periodicity along the waveguide. We calculate the mode profile of a PSW in a region far away from the bandgap and we showed that it is comparable to the mode profile of the equivalent CWG even for relatively high values of averaged refractive index contrast.
This paper considers abnormal blocking of a guided mode propagating in a silicon optical waveguide with periodic tunnelling inserts. Using an independent two-dimensional analysis by the method of lines (MoL) and direc...
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This paper considers abnormal blocking of a guided mode propagating in a silicon optical waveguide with periodic tunnelling inserts. Using an independent two-dimensional analysis by the method of lines (MoL) and direct simulation by the finite-difference time-domain (FDTD) method, we have identified additional signal blocking bands, unrelated to Bragg conversion to backward guided modes of the parent silicon waveguide. These bands are due to the conversion of the incident wave energy to a leaky quasi-mode of the periodically segmented structure, which subsequently transfers the energy to the ambient medium in the form of radiation modes. A distinctive feature of this phenomenon is resonant coupling of the guided mode of the strip waveguide with its radiation modes, which is due to the weak tunnel coupling with the periodically segmented structure. This structure does not support independent guided propagation, so the energy stored in it is re-emitted to space. The abnormal blocking effect may find application in optical telecommunications elements and in the fabrication of optical sensors.
The present paper focuses on the theoretical characterization and simulation of different graded index segmented LiNbO3 waveguides. Several dependencies of the refractive index versus the z direction of propagation of...
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The present paper focuses on the theoretical characterization and simulation of different graded index segmented LiNbO3 waveguides. Several dependencies of the refractive index versus the z direction of propagation of the applied laser field are examined and a comparative discussion is made, taking into account dispersive and attenuation losses.
A new design scheme of a wavelength demultiplexer device structure using waveguide mirrors to generate a series of reflected light beams with wavelength dependent phases is proposed. The light propagated in the wavegu...
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A new design scheme of a wavelength demultiplexer device structure using waveguide mirrors to generate a series of reflected light beams with wavelength dependent phases is proposed. The light propagated in the waveguide is reflected into a planar waveguide at multiple, partially reflecting mirrors, in which positions and a geometry of the waveguide are optimized to lower the filter response difference between the output ports. Methods to reduce the sidelobe level in the filter response are demonstrated. (C) 2002 society of Photo-Optical Instrumentation Engineers.
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