Journal Article•
Correction to «normal mode analysis of waveguide devices. I: Theory» and «normal mode analysis of waveguide devices. II: Device output and crosstalk»
01 Jan 1989-Journal of Lightwave Technology (Institute of Electrical and Electronics Engineers)-Vol. 7, Iss: 9
TL;DR: In this article, a correction d'erreur dans light wave technologie, vol. 6, pp. 1051-1057, 1988, is presented.
Abstract: Correction d'erreur dans Light wave Technologie, vol. 6, pp. 1051-1057, 1988. Correction d'erreur dans light wave technologie, vol. 6, pp. 1058-1068, 1988
Citations
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TL;DR: In this paper, an analysis of the operation of the parallel waveguide directional coupler by incorporating eigenmode phase shifts in the input and output transition regions is made, and conditions for symmetric switching are derived.
Abstract: An analysis is made of the operation of the parallel waveguide directional coupler by incorporating eigenmode phase shifts in the input and output transition regions. The set of modes used in the analysis consists of the orthogonal symmetric and antisymmetric modes of the unperturbed parallel waveguide. It is demonstrated how the switching diagram changes as the transitional phase shifts increase. There is no indication that these built-in phase shifts degrade coupler crosstalk performance for the states normally used. Conditions for symmetric switching are derived. >
9 citations
TL;DR: In this paper, the effect of passive phase shift regions on the performance characteristics of parallel waveguide couplers is considered, in particular a longitudinal electrode gap in addition to phase shifts in the adiabatic input and output taper regions.
Abstract: The effect of passive phase shift regions on the performance characteristics of parallel waveguide couplers is considered. In particular, a longitudinal electrode gap in addition to phase shifts in the adiabatic input and output taper regions is considered. Both types of phase shifts have a degrading impact on the accessibility of some switching states. However, an electrode gap combined with taper region phase shifts may be beneficial for certain traveling wave electrode configurations. For a certain combination of gap and electrode lengths a through state with better than 30 dB crosstalk over an extended voltage range has been identified. >
2 citations
TL;DR: In this paper, a polymeric variable optical attenuator using a modified wide angle X-junction structure was proposed, which has an attenuation range larger than 34dB for TE polarization by means of thermo-optic tuning.
Abstract: We propose a polymeric variable optical attenuator using a modified wide angle X-junction structure. The device's size is only one sixth of that using conventional Y-junction structure. A commercial 3D-Beam Propagation Method simulation software was used to optimize and analyze our design, which was then fabricated using benzocyclobutene polyimide. The experimental results well match with the simulation results. The VOA has an attenuation range larger that 34dB for TE polarization by means of thermo-optic tuning. The measured response time was about 100 micro second, which is fast in compared with other thermo-optic device. The compactness of our device makes it very suitable for high density integrated photonics circuits.
2 citations
01 Oct 1996
TL;DR: In this article, the influence of gravity-driven buoyancy on the thickness of thin films of metal-free phthalocyanine has been investigated in a low gravity environment.
Abstract: Experimentally, many of the functions of electrical circuits have been demonstrated using optical circuits and, in theory, all of these functions may be accomplished using optical devices made of nonlinear optical materials. Actual construction of nonlinear optical devices is one of the most active areas in all optical research being done at this time. Physical vapor transport (PVT) is a promising technique for production of thin films of a variety of organic and inorganic materials. Film optical quality, orientation of microcrystals, and thickness depends critically on type of material, pressure of buffer gas and temperature of deposition. An important but understudied influence on film characteristics is the effect of gravity-driven buoyancy. Frazier, Hung, Paley, Penn and Long have recently reported mathematical modelling of the vapor deposition process and tested the predictions of the model on the thickness of films grown by PVT of 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-l-ol (DAMNA). In an historic experiment, Debe, et. al. offered definitive proof that copper phthalocyanine films grown in a low gravity environment are denser and more ordered than those grown at 1 g. This work seeks to determine the influence on film quality of gravity driven buoyancy in the low pressure PVT film growth of metal-free phthalocyanine.
1 citations
TL;DR: In this paper, a simple method of calculating the imaginary part of the propagation constant in a lossy waveguide that closely follows the effective index method of finding the real propagation constant of a rectangular dielectric guide was developed.
Abstract: We have developed a simple method of calculating the imaginary part of the propagation constant in a lossy waveguide that closely follows the effective-index method of finding the real propagation constant of a rectangular dielectric guide. The method gives values much in agreement with the exact values obtained by the circular-harmonics method. The method has been used in the improved coupled-mode analysis of coupled-multiple-quantum-well waveguides developed by Tsang and Chuang. Three different configurations of coupled waveguides have been considered: slab, buried-channel, and strip-loaded waveguide directional couplers, where excitonic electrorefraction in multiquantum wells has been utilized to accomplish the switching. The output power-electric field curves calculated by using the above method agree closely in all three cases with similar curves obtained by using a complex propagation constant calculated by a numerical two-dimensional root-searching technique. The present method simplifies the design and optimization of coupled-waveguide devices and its application is illustrated in the case of multiple-quantum-well directional couplers. >
1 citations
References
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TL;DR: In this paper, an improved coupled-mode equation for parallel dielectric waveguides was derived by using a newly found relationship that connects the propagation constants of the individual guides to the coupling coefficients via an overlap integral that measures the guides' proximity.
Abstract: An improved version of coupled-mode equations for parallel dielectric waveguides has been derived by using a newly found relationship that connects the propagation constants of the individual guides to the coupling coefficients via an overlap integral that measures the guides' proximity. The four parameters of these new coupled equations are simple functions of essentially one single quantity: the asynchronism of the individual guides properly normalized.
254 citations
TL;DR: In this article, an experimental electro-optical switched directional coupler is reported which is formed in LiNbO3 by diffused Ti strip waveguides and uses stepped reversed phase mismatching to provide electrical adjustment of both switch states.
Abstract: An experimental electro‐optical switched directional coupler is reported which is formed in LiNbO3 by diffused Ti strip waveguides and uses stepped reversed phase mismatching to provide electrical adjustment of both switch states. A measured 400:1 conversion of light from one guide to the other was obtained.
199 citations
TL;DR: In this article, an analytic solution for power transfer for structures whose shape has a particular functional form is provided for structures fabricated with Ti:LiNbO 3 channel waveguides.
Abstract: Mode coupling between local normal modes in branching and separating optical waveguides is treated. An analytic solution for power transfer is provided for structures whose shape has a particular functional form. Analytic results are compared to numerical calculations for linear branches. Numerical examples for the design of shaped structures fabricated with Ti:LiNbO 3 channel waveguides are given.
98 citations
TL;DR: In this article, the authors show that tapering may be used to eliminate cross talk while maintaining negligible radiation and reflection loss in a waveguide directional couplers with unequal excitation of symmetric and antisymmetric modes.
Abstract: Waveguide directional couplers may suffer from incomplete isolation between channels due to unequal excitation of symmetric and antisymmetric coupler modes. This letter shows that tapering may be used to eliminate cross talk while maintaining negligible radiation and reflection loss.
81 citations
TL;DR: Close form solutions to the coupled-mode equations with variable coupling coefficient are presented and a procedure for the design of the best geometry of a variety of applications utilizing variable spacing couplers is presented.
Abstract: Optical directional couplers with variable separation are introduced and analyzed. Closed form solutions to the coupled-mode equations with variable coupling coefficient are presented. A procedure for the design of the best geometry of a variety of applications utilizing variable spacing couplers is also presented.
77 citations