FOTONICA - Grup de Recerca de Fotònica
http://hdl.handle.net/2117/3270
Tue, 03 May 2016 07:03:11 GMT2016-05-03T07:03:11ZLeaky modes in multilayer anisotropic optical waveguides
http://hdl.handle.net/2117/86257
Leaky modes in multilayer anisotropic optical waveguides
Torner Sabata, Lluís; Canal Bienzobas, Fernando; Hernández Marco, Jordi
The propagation characteristics of the leaky modes in planar anisotropic waveguides with a multilayer structure have been investigated by means of a compact rigorous formalism. The leakage losses and leaky transition angle have been studied for the fundamental and first hybrid modes. An inhomogeneous waveguide and buffered step index type structure have been discussed. Particular attention has been devoted to the variation of the loss coefficient of the leaky modes as a function of buffer thickness and buffer refractive index. A notably different behavior has been obtained for various configurations.
Wed, 27 Apr 2016 13:04:06 GMThttp://hdl.handle.net/2117/862572016-04-27T13:04:06ZTorner Sabata, LluísCanal Bienzobas, FernandoHernández Marco, JordiThe propagation characteristics of the leaky modes in planar anisotropic waveguides with a multilayer structure have been investigated by means of a compact rigorous formalism. The leakage losses and leaky transition angle have been studied for the fundamental and first hybrid modes. An inhomogeneous waveguide and buffered step index type structure have been discussed. Particular attention has been devoted to the variation of the loss coefficient of the leaky modes as a function of buffer thickness and buffer refractive index. A notably different behavior has been obtained for various configurations.Non reciprocal phase matching in four-layer magnetooptical waveguides
http://hdl.handle.net/2117/86211
Non reciprocal phase matching in four-layer magnetooptical waveguides
Hernández Marco, Jordi; Canal Bienzobas, Fernando; Torner Sabata, Lluís
Non reciprocal single-mode conversion TE0¿TM0 in a four-layer magnetooptical waveguide has been studied as a function of the external applied magnetic field.
Tue, 26 Apr 2016 15:27:07 GMThttp://hdl.handle.net/2117/862112016-04-26T15:27:07ZHernández Marco, JordiCanal Bienzobas, FernandoTorner Sabata, LluísNon reciprocal single-mode conversion TE0¿TM0 in a four-layer magnetooptical waveguide has been studied as a function of the external applied magnetic field.Applicability of the.Lorentzian peak method to analyze leaky and lossy optical waveguides
http://hdl.handle.net/2117/84983
Applicability of the.Lorentzian peak method to analyze leaky and lossy optical waveguides
Torner Sabata, Lluís; Canal Bienzobas, Fernando
Several conclusions concerning the applicability of the Lorentzian peak method to compute the complex propagation constant of leaky and lossy waveguide modes are established.
Thu, 31 Mar 2016 13:21:27 GMThttp://hdl.handle.net/2117/849832016-03-31T13:21:27ZTorner Sabata, LluísCanal Bienzobas, FernandoSeveral conclusions concerning the applicability of the Lorentzian peak method to compute the complex propagation constant of leaky and lossy waveguide modes are established.Reglas de similitud para modos TE en guias opticas no lineales
http://hdl.handle.net/2117/84979
Reglas de similitud para modos TE en guias opticas no lineales
Torres, Josep Lluis; Torner Sabata, Lluís
We have shown that the stationary propcrties ofTE guided waves in a slab optical waveguide with a nonlinear Kerr-likc bounding medium can be described in a compact way by means of the usual normalized dfcctive moda.! index (ú) and a set of only four independent normalized pa.ranwt.<•rs: t he• WC'II-known normalized thickness (V) a.nd asymmetry measure (a) of the wa.vPguide, the generalizcd a.<;pect ratio between film and substrate refractive indices a.nd a JH'W guidc•d pown mensure. Allowed a.nd forbidden regions in the {b, V,a}-space in ordcr t.hat. a gui<IC'd solut.ion cxists ha.ve been recognized and classified. As a further application or the IIOI'ln<tlized paramet.ers, we focus on the cutoff properties of the T Eo guided wave.
Thu, 31 Mar 2016 12:56:10 GMThttp://hdl.handle.net/2117/849792016-03-31T12:56:10ZTorres, Josep LluisTorner Sabata, LluísWe have shown that the stationary propcrties ofTE guided waves in a slab optical waveguide with a nonlinear Kerr-likc bounding medium can be described in a compact way by means of the usual normalized dfcctive moda.! index (ú) and a set of only four independent normalized pa.ranwt.<•rs: t he• WC'II-known normalized thickness (V) a.nd asymmetry measure (a) of the wa.vPguide, the generalizcd a.<;pect ratio between film and substrate refractive indices a.nd a JH'W guidc•d pown mensure. Allowed a.nd forbidden regions in the {b, V,a}-space in ordcr t.hat. a gui<IC'd solut.ion cxists ha.ve been recognized and classified. As a further application or the IIOI'ln<tlized paramet.ers, we focus on the cutoff properties of the T Eo guided wave.Fabricacion y caracterizacion de guias opticas integradas sobre sustratos de silicio
http://hdl.handle.net/2117/84974
Fabricacion y caracterizacion de guias opticas integradas sobre sustratos de silicio
Torner Sabata, Lluís; Alcubilla González, Ramón; Calderer Cardona, Josep
Silicon nitride (Si 3 N4 ) planar aplica! waveguidcs have been successfully grown by lowpressure chemical vapor dcposition (LPCVD). Silicon p-type wafers with a (100) orientation were used as subst.ratcs, aiiC! t.he Si3 N.1 was separated from the lossy Si substrate by a thermally grown SiO~ t.hin film.
Thu, 31 Mar 2016 12:31:31 GMThttp://hdl.handle.net/2117/849742016-03-31T12:31:31ZTorner Sabata, LluísAlcubilla González, RamónCalderer Cardona, JosepSilicon nitride (Si 3 N4 ) planar aplica! waveguidcs have been successfully grown by lowpressure chemical vapor dcposition (LPCVD). Silicon p-type wafers with a (100) orientation were used as subst.ratcs, aiiC! t.he Si3 N.1 was separated from the lossy Si substrate by a thermally grown SiO~ t.hin film.Suppression and restoration of disorder-induced light localization mediated by PT-symmetry breaking
http://hdl.handle.net/2117/84920
Suppression and restoration of disorder-induced light localization mediated by PT-symmetry breaking
Kartashov, Yaroslav V.; Hang, Chao; Konotop, Vladimir V; Vysloukh, Victor A.; Huang, Guoxiang; Torner Sabata, Lluís
We uncover that the breaking point of the PT-symmetry in optical waveguide arrays has a dramatic impact on light localization induced by the off-diagonal disorder. Specifically, when the gain/loss control parameter approaches a critical value at which PT-symmetry breaking occurs, a fast growth of the coupling between neighboring waveguides causes diffraction to dominate to an extent that light localization is strongly suppressed and the statistically averaged width of the output pattern substantially increases. Beyond the symmetry-breaking point localization is gradually restored, although in this regime the power of localized modes grows upon propagation. The strength of localization monotonically increases with disorder at both broken and unbroken PT-symmetry. Our findings are supported by statistical analysis of parameters of stationary eigenmodes of disordered-symmetric waveguide arrays and by analysis of dynamical evolution of single-site excitations in such structures. Parity-time (PT)- symmetric waveguides feature real spectra despite the presence of gain and losses. A spectrum becomes complex at the symmetry-breaking point as the guide characteristics are changed. This paper reports on disorder-induced localization caused by off-diagonal disorder introduced into a PT-symmetric periodic waveguide array. Localization is suppressed near and restored far beyond the symmetry-breaking point. The phenomenon is explained by enhancement of the diffraction in the symmetry-breaking point.
Wed, 30 Mar 2016 18:53:04 GMThttp://hdl.handle.net/2117/849202016-03-30T18:53:04ZKartashov, Yaroslav V.Hang, ChaoKonotop, Vladimir VVysloukh, Victor A.Huang, GuoxiangTorner Sabata, LluísWe uncover that the breaking point of the PT-symmetry in optical waveguide arrays has a dramatic impact on light localization induced by the off-diagonal disorder. Specifically, when the gain/loss control parameter approaches a critical value at which PT-symmetry breaking occurs, a fast growth of the coupling between neighboring waveguides causes diffraction to dominate to an extent that light localization is strongly suppressed and the statistically averaged width of the output pattern substantially increases. Beyond the symmetry-breaking point localization is gradually restored, although in this regime the power of localized modes grows upon propagation. The strength of localization monotonically increases with disorder at both broken and unbroken PT-symmetry. Our findings are supported by statistical analysis of parameters of stationary eigenmodes of disordered-symmetric waveguide arrays and by analysis of dynamical evolution of single-site excitations in such structures. Parity-time (PT)- symmetric waveguides feature real spectra despite the presence of gain and losses. A spectrum becomes complex at the symmetry-breaking point as the guide characteristics are changed. This paper reports on disorder-induced localization caused by off-diagonal disorder introduced into a PT-symmetric periodic waveguide array. Localization is suppressed near and restored far beyond the symmetry-breaking point. The phenomenon is explained by enhancement of the diffraction in the symmetry-breaking point.Normalized parameters for Y-branch optical waveguides
http://hdl.handle.net/2117/84642
Normalized parameters for Y-branch optical waveguides
Recolons Martos, Jaume; Torner Sabata, Lluís; Canal Bienzobas, Fernando
Y-branch optical waveguides are analyzed in terms of normalized parameters by means of the usual modal analysis. With these parameters the number of variables of the problem is reduced, and universal plots for the mode conversion are obtained. Our results show that the normalized parameters are useful for the design of branching waveguides more tolerant of fabrication errors.
Thu, 17 Mar 2016 14:35:14 GMThttp://hdl.handle.net/2117/846422016-03-17T14:35:14ZRecolons Martos, JaumeTorner Sabata, LluísCanal Bienzobas, FernandoY-branch optical waveguides are analyzed in terms of normalized parameters by means of the usual modal analysis. With these parameters the number of variables of the problem is reduced, and universal plots for the mode conversion are obtained. Our results show that the normalized parameters are useful for the design of branching waveguides more tolerant of fabrication errors.Reglas de escala para bifurcaciones en guías ópticas
http://hdl.handle.net/2117/84499
Reglas de escala para bifurcaciones en guías ópticas
Recolons Martos, Jaume; Torner Sabata, Lluís; Canal Bienzobas, Fernando
Wed, 16 Mar 2016 14:05:57 GMThttp://hdl.handle.net/2117/844992016-03-16T14:05:57ZRecolons Martos, JaumeTorner Sabata, LluísCanal Bienzobas, FernandoNoise-assisted energy transport in electrical oscillator networks with off-diagonal dynamical disorder
http://hdl.handle.net/2117/84496
Noise-assisted energy transport in electrical oscillator networks with off-diagonal dynamical disorder
De León Montiel, J. Roberto; Quiroz Juarez, Mario A.; Quintero Torres, Rafael; Domínguez Juárez, Jorge Luis; Moya Cessa, Hector M.; Pérez Torres, Juan; ARAGÓN HERNÁNDEZ, JOSÉ LUÍS
Noise is generally thought as detrimental for energy transport in coupled oscillator networks. However, it has been shown that for certain coherently evolving systems, the presence of noise can enhance, somehow unexpectedly, their transport efficiency; a phenomenon called environment-assisted quantum transport (ENAQT) or dephasing-assisted transport. Here, we report on the experimental observation of such effect in a network of coupled electrical oscillators. We demonstrate that by introducing stochastic fluctuations in one of the couplings of the network, a relative enhancement in the energy transport efficiency of 22.5 ± 3.6% can be observed.
Wed, 16 Mar 2016 13:49:51 GMThttp://hdl.handle.net/2117/844962016-03-16T13:49:51ZDe León Montiel, J. RobertoQuiroz Juarez, Mario A.Quintero Torres, RafaelDomínguez Juárez, Jorge LuisMoya Cessa, Hector M.Pérez Torres, JuanARAGÓN HERNÁNDEZ, JOSÉ LUÍSNoise is generally thought as detrimental for energy transport in coupled oscillator networks. However, it has been shown that for certain coherently evolving systems, the presence of noise can enhance, somehow unexpectedly, their transport efficiency; a phenomenon called environment-assisted quantum transport (ENAQT) or dephasing-assisted transport. Here, we report on the experimental observation of such effect in a network of coupled electrical oscillators. We demonstrate that by introducing stochastic fluctuations in one of the couplings of the network, a relative enhancement in the energy transport efficiency of 22.5 ± 3.6% can be observed.Diffraction control in P T -symmetric photonic lattices: from beam rectification to dynamic localization
http://hdl.handle.net/2117/84253
Diffraction control in P T -symmetric photonic lattices: from beam rectification to dynamic localization
Kartashov, Yaroslav V.; Vysloukh, Victor A.; Konotop, Vladimir V; Torner Sabata, Lluís
We address the propagation of light beams in longitudinally modulated PT-symmetric lattices, built as arrays of couplers with periodically varying separation between their channels, and show a number of possibilities for efficient diffraction control available in such nonconservative structures. The dynamics of light in such lattices crucially depends on the ratio of the switching length for the straight segments of each coupler and the longitudinal lattice period. Depending on the longitudinal period, one can achieve either beam rectification when the input light propagates at a fixed angle across the structure without diffractive broadening or dynamic localization when the initial intensity distribution is periodically restored after each longitudinal period. Importantly, the transition between these two different propagation regimes can be achieved by tuning only gain and losses acting in the system, provided that the PT symmetry remains unbroken. The impact of Kerr nonlinearity is also discussed.
Fri, 11 Mar 2016 18:26:54 GMThttp://hdl.handle.net/2117/842532016-03-11T18:26:54ZKartashov, Yaroslav V.Vysloukh, Victor A.Konotop, Vladimir VTorner Sabata, LluísWe address the propagation of light beams in longitudinally modulated PT-symmetric lattices, built as arrays of couplers with periodically varying separation between their channels, and show a number of possibilities for efficient diffraction control available in such nonconservative structures. The dynamics of light in such lattices crucially depends on the ratio of the switching length for the straight segments of each coupler and the longitudinal lattice period. Depending on the longitudinal period, one can achieve either beam rectification when the input light propagates at a fixed angle across the structure without diffractive broadening or dynamic localization when the initial intensity distribution is periodically restored after each longitudinal period. Importantly, the transition between these two different propagation regimes can be achieved by tuning only gain and losses acting in the system, provided that the PT symmetry remains unbroken. The impact of Kerr nonlinearity is also discussed.