147 research outputs found

    Integrated optics refractometry: sensitivity in relation to spectral shifts

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    A new variant of the Vernier-effect based sensor reported in ref. 1 is introduced. Both sensor types may show a huge index induced spectral shift. It will be shown in a poster presentation that with such sensors, as well as with surface plasmon based sensors, the constraints on the spectral resolution of the read out are strongly relaxed, but the sensitivity is not increased (unlike what is often reported in the literature)

    Design of spectrometers and polarization splitters using adiabatically connected slab waveguides

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    The design of fully integrated prism spectrometers and polarization splitters in adiabatically connected slab waveguides with two different thicknesses, using principles of geometrical optics, is presented. In addition, the design of mirrors to connect these devices to input and output waveguides is discussed. The proposed structures will be fabricated, using two wet-etching steps, in a Si3N4 layer in-between a buffer and cladding SiO2 layer

    Design of a spiral-shaped Mach Zehnder interferometric sensor for refractive index sensing of watery solutions

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    The design of a spiral-shaped Mach-Zehnder Interferometric sensor (sMZI sensor) for refractive index sensing of watery solutions is presented. The goal of the running project is to realise a multi-sensing array by placing multiple sMZIs in series to form a sensing branch, and to place several sensing branches in parallel. In such an arrangment it is possible to use a single light source for several sensors. Each sensor will contain an electro-optical modulator, which makes it possible to separately interrogate and accurately read-out each sensor in the same sensing branch

    Efficient interface conditions for the finite difference beam propagation method

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    It is shown that by adapting the refractive indexes in the vicinity of interfaces, the 2-D beam propagation method based on the finite-difference (FDBPM) scheme can be made much more effective. This holds especially for TM modes propagating in structures with high-index contrasts, such as surface polaritons. A short discussion is given on the applicability of the FDBP

    Modulation-frequency encoded multi-wavelength fluorescence analysis

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    We introduce a principle of parallel optical processing: modulation-frequency-encoded multi-wavelength laser excitation, fluorescence detection with a single detector, and Fourier analysis decoding. As an example, we demonstrate simultaneous detection of DNA fragments from different origins

    On the accuracy of the finite difference method for applications in beam propagating techniques

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    In this paper it is shown that the inaccuracy in the beam propagation method based on the finite difference scheme, introduced by the use of the slowly varying envelope approximation, can be overcome in an effective way. By the introduction of a perturbation expansion the accuracy can be improved as much as wanted, often nearly without any increase of the computation time. An error analysis is given and the method is illustrated by an example
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