In this paper the power coupling expression between two identical axially aligned and spatially separated waveguides is presented. Calculations using the coupling expression for a Gaussian mode profile in the input wa...
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In this paper the power coupling expression between two identical axially aligned and spatially separated waveguides is presented. Calculations using the coupling expression for a Gaussian mode profile in the input waveguide produce results that are in excellent agreement with experimental observations.
We report on techniques for measuring photoinduced diffraction in prism-coupled slab polymer waveguides. Diffraction effects resulting from photochromic gratings in slab waveguides of Disperse Red 1 dye in polymethylm...
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We report on techniques for measuring photoinduced diffraction in prism-coupled slab polymer waveguides. Diffraction effects resulting from photochromic gratings in slab waveguides of Disperse Red 1 dye in polymethylmethacrylate were studied. Optical damage in the form of diffractive mode conversion was observed when we coupled in light with a wavelength slightly longer than the absorption edge of Disperse Red 1 dye. Slowly growing satellite beams in the outcoupled light were attributed to anisotropic scattering between the lowest-order TE mode and the lowest-order TM mode caused by self-diffraction from a grating produced through the photochromic effect. We have also investigated the effect of made-coupling changes on the determination of diffraction efficiency and sensitivity in waveguide experiments. Diffraction efficiencies predicted by measurements of the modulation depth in the guide are found to overstate the actual diffraction efficiencies that could be observed in this geometry. Techniques for overcoming this limitation and for improving estimates of the energy density and interaction length in the guide are noted.
The eigenvalue problem for the determination of propagation modes in a waveguide filled with a homogeneous chiroferrite medium is formulated. As an illustrative example the circular chiroferrite waveguide is analyzed,...
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The eigenvalue problem for the determination of propagation modes in a waveguide filled with a homogeneous chiroferrite medium is formulated. As an illustrative example the circular chiroferrite waveguide is analyzed, and the corresponding dispersion relations and diagrams are obtained.
We have fabricated single-mode channel waveguides using Na+/K+ ion exchange in CdSxSe1-x-doped glasses. Optically induced saturable absorption in these waveguides has been found in the mW guided power range at 514.5 n...
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We have fabricated single-mode channel waveguides using Na+/K+ ion exchange in CdSxSe1-x-doped glasses. Optically induced saturable absorption in these waveguides has been found in the mW guided power range at 514.5 nm wavelength. Observation of apparent time delay on the order of 100 ns between input and output light pulses and its extinction is also reported.
A photonic inter-module connector for near-future electronic switching systems is demonstrated through the use of silica-based 8 X 8 optical switches. A small-scale switch matrix is sufficient because the near-future ...
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A photonic inter-module connector for near-future electronic switching systems is demonstrated through the use of silica-based 8 X 8 optical switches. A small-scale switch matrix is sufficient because the near-future systems will consist of a limited number of modules. If an active module is affected by a fatal fault or accident, a stand-by module must quickly take its place. The experimental photonic inter-module connector can switch 156-Mbit/s photonic interconnections between seven subscriber-line-concentrator modules and eight circuit-switching modules.
Ion-exchanged KTiOPO4 (KTP) planar optical waveguides are formed in X, Y, and Z cuts of KTP single crystals with Rb+ --> K+, Cs+ --> K+, and Ag+ --> K+ ion exchanges from nitrate melts. waveguide modes, index...
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Ion-exchanged KTiOPO4 (KTP) planar optical waveguides are formed in X, Y, and Z cuts of KTP single crystals with Rb+ --> K+, Cs+ --> K+, and Ag+ --> K+ ion exchanges from nitrate melts. waveguide modes, index profiles, and birefringence of the waveguides are studied with the integrated optics technique. Electron probe microanalysis is applied to determine an elemental composition of the ion-exchanged structures and x-ray diffractometry is used to study crystalline structure of the waveguides. The research enabled us to produce KTP optical waveguides by silver ion diffusion for the first time. In addition, the residual potassium concentrations after the ion exchange are measured and the distribution profiles of Cs and Rb atoms and positions of the atoms in the KTP lattice are characterized. A study of the unit cell deformations accompanied by birefringence measurements enabled us to clarify differences in Rb+ --> K+ and Cs+ --> K+ ion exchanges. A novel approach that would produce a KTP optical waveguide with higher index increase and better crystalline perfection than Rb+ --> K+ and Cs+ --> K+ ion exchanges is proposed.
The scattering characteristics of a guided wave by a class of discontinuities in a non-radiative dielectric (NRD) guide are systematically investigated by a method which combines the building block approach of multimo...
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The scattering characteristics of a guided wave by a class of discontinuities in a non-radiative dielectric (NRD) guide are systematically investigated by a method which combines the building block approach of multimode network theory with a rigorous mode-matching procedure. Some experimental data justify the effectiveness and accuracy of the present method. Extensive numerical results are obtained to develop useful guidelines for the design of NRD guide components.
Polarisation-independent operation of an unstrained InGaAsP/InGaAsP multiquantum well electroabsorption modulator is reported. Contrast ratios of 20 and 30 dB for 400 mum long devices have been achieved at 2.0 and 5.5...
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Polarisation-independent operation of an unstrained InGaAsP/InGaAsP multiquantum well electroabsorption modulator is reported. Contrast ratios of 20 and 30 dB for 400 mum long devices have been achieved at 2.0 and 5.5V reverse bias voltage, respectively, with on-state attenuation less that 2 dB and at 1.55 mum wavelength. Polarisation sensitivity at these voltage values is found vanish.
The investigation of a refractometer principle based on index-sensitive resonant wavelength shifts in a fibre-to-planar-waveguide coupler is reported. Device fabrication, involving spin deposition and curing of a poly...
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The investigation of a refractometer principle based on index-sensitive resonant wavelength shifts in a fibre-to-planar-waveguide coupler is reported. Device fabrication, involving spin deposition and curing of a polymer onto a side-polished single-mode optical fibre, is relatively straightforward. Three devices of differing polymer waveguide thickness were fabricated and tested, and in all cases there was excellent agreement between experiment and a simple model of operation. The results demonstrated that index resolution down to about 10(-5) is realistic. In addition, an active transducer, based on electrooptic polymers for closed-loop operation, was proposed and investigated.
A new laser beam (LB) writing technique that can provide dot lines of a nearly 10-mum period in photoresist, with a period fluctuation of less than 4 nm, is proposed and demonstrated. The dot period is also controllab...
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A new laser beam (LB) writing technique that can provide dot lines of a nearly 10-mum period in photoresist, with a period fluctuation of less than 4 nm, is proposed and demonstrated. The dot period is also controllable with an accuracy of the order of a nanometer. The so-called LB periodic-dot writing has been successfully applied for definition of interdigital electrodes required for TE-TM mode conversion in Ti:LiNbO3 waveguide wavelength filters, in which the electrode period was nearly 10 mum at the center wavelength of the filter around 0.8 mum. The fabricated filter with a 5-mm-long LB-written interdigital electrode exhibited a filter bandwidth of 1.1 nm, which was in good agreement with the theoretical value. Eight filters with a period difference of 80 nm were then integrated on a LiNbO3 chip;as a result, the center-wavelength spacing between the adjacent filters was measured to be 5.4 +/- 0.6 nm, as expected. Such fine control of the electrode period has thus become possible by the LB periodic-dot writing that was demonstrated. The writing accuracy is also discussed in detail along with the system description.
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