The vectorial method of lines is applied to the longitudinal discontinuities of slab waveguides. The analysis includes reflections, radiation losses and absorption by lossy dielectrics. In spite of the generality of t...
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The vectorial method of lines is applied to the longitudinal discontinuities of slab waveguides. The analysis includes reflections, radiation losses and absorption by lossy dielectrics. In spite of the generality of the analysis the numerical effort is low and implementation on a computer is easy.
The tuning characteristics of ridge waveguide DBR lasers have been measured under CW and pulsed grating currents. Under CW grating current injection, a maximum tuning range of 2.5 nm was measured. This tuning range wa...
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The tuning characteristics of ridge waveguide DBR lasers have been measured under CW and pulsed grating currents. Under CW grating current injection, a maximum tuning range of 2.5 nm was measured. This tuning range was extended to almost 7 nm under pulsed conditions. The increase in the tuning range is explained by the absence of thermal tuning mechanisms for pulsed grating currents and the dominance of thermal tuning in the ridge waveguide structure at large CW grating currents is explicitly shown.
An all-optical, nonlinear grating coupling has been observed in a passive InGaAs/InP MQW planar waveguide at room temperture. It is shown that thermal effects can be ruled out, and that the mechanism responsible for t...
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An all-optical, nonlinear grating coupling has been observed in a passive InGaAs/InP MQW planar waveguide at room temperture. It is shown that thermal effects can be ruled out, and that the mechanism responsible for the refractive nonlinearity is consistent with purely excitonic effects. Switching power density is believed to be lower than in previous studies.
A coplanar waveguide radial line stub resonator is experimentally characterised with respect to stub radius, sectoral angle, substrate thickness and relative dielectric constant. A simple closed-form design equation, ...
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A coplanar waveguide radial line stub resonator is experimentally characterised with respect to stub radius, sectoral angle, substrate thickness and relative dielectric constant. A simple closed-form design equation, which predicts the resonance radius of the stub, is presented.
The pulsed FDTD method is used to analyse multiport junctions in recgtangular waveguide. Two representative examples are considered, namely the H-plane tee junction and the folded H-plane tee junction. Computed result...
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The pulsed FDTD method is used to analyse multiport junctions in recgtangular waveguide. Two representative examples are considered, namely the H-plane tee junction and the folded H-plane tee junction. Computed results for the scattering parameters are compared to measurements performed by the authors.
A finite-difference beam-propagation method is derived directly from the vectorial Maxwell equations. The new approach allows the analysis of coupling between various components of the electric-field vector for optica...
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A finite-difference beam-propagation method is derived directly from the vectorial Maxwell equations. The new approach allows the analysis of coupling between various components of the electric-field vector for optical beam propagating in dielectric waveguides as well as corresponding changes in the beam-polarisation state.
Guided-wave directional couplers having good polarisation-maintaining characteristics have been made in glass and assembled with polarisation maintaining fibre arrays fabricated by a novel technique using capillaries ...
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Guided-wave directional couplers having good polarisation-maintaining characteristics have been made in glass and assembled with polarisation maintaining fibre arrays fabricated by a novel technique using capillaries on a V-grooved substrate. The extinction ratios of the output ports were over 31 dB for waveguide chips and 26 dB for fibre array-assembled devices, respectively.
Efficient electroabsorption in an InGaAsP/InGaAsP MQW optical waveguide modulator structure is reported. A 17 dB extinction ratio is obtained by applying a 3.5 V drive voltage to a 78-mu-m long waveguide operating at ...
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Efficient electroabsorption in an InGaAsP/InGaAsP MQW optical waveguide modulator structure is reported. A 17 dB extinction ratio is obtained by applying a 3.5 V drive voltage to a 78-mu-m long waveguide operating at 1.54-mu-m under TE-polarisation mode. The on-state attenuation is only 2 dB.
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.
Two new techniques for exciting a linearly tapered slot antenna (LTSA) with coplanar waveguide (CPW) are introduced. In the first approach, an air bridge is used to couple power from a CPW to an LTSA. In the second ap...
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Two new techniques for exciting a linearly tapered slot antenna (LTSA) with coplanar waveguide (CPW) are introduced. In the first approach, an air bridge is used to couple power from a CPW to an LTSA. In the second approach, power is electromagnetically coupled from a finite CPW (FCPW) to an LTSA. Measured results at 18 GHz show excellent return loss and radiation patterns.
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