Francisco J. Diaz-Otero

Interchannel Soliton Collisions in Periodic Dispersion Maps in the Presence of Third Order Dispersion

We study the effects of third-order dispersion in wavelength division multiplexed soliton transmission systems using periodic dispersion maps. For this purpose, loss and lumped amplification have been included in a previous ODE model obtained using the variational method and a Gaussian ansatz. We present a detailed analysis of how TOD affects the collision-induced frequency shifts of the transmitted pulses.

Micro-Ring Chains With High-Order Resonances

We analyze micro-ring resonator chains that have a system response with N-th order poles and zeroes when the chain consists of N unit cells. These include the recently proposed zigzag micro-ring resonator chains exhibiting new fast- and slow- light properties and a dual ring chain for which the explicit expression of the system function is given. We discuss the realization of ultrahigh order structures with sharp peaks and large out-of-band rejection filters, ultra-sharp notch optical filters for optical carrier suppression and the general properties of slow and fast light phenomena in this type of systems. All the analyses are based on the pole-zero representation of the system function. A tuning mechanism for the modified dual-ring structures acting as notch filters is also proposed.

original article: Effects of the amplifier location in interchannel soliton collisions in periodic dispersion maps in the presence of third order dispersion

Abstract: We analyze the effects of third order dispersion in wavelength division multiplexed dispersion-managed soliton transmission systems using an ordinary differential equations model obtained by the variational method. Interchannel soliton collisions in this type of transmission systems produce shifts of their center frequencies which result in a timing jitter at the receiver that can severely impair signal transmission. We investigate how the third order dispersion term affects the collision-induced residual frequency shifts as the amplifier location within a period of the dispersion map is varied. The validity of the model employed in the analysis is assessed by comparing the variational results with direct simulations of the partial differential equations for specific cases, finding excellent agreement.

Higher-order interaction-induced effects between strong dispersion-managed solitons with dissimilar powers

We address one of the major penalties associated with the transmission of optical solitons in fiber-optic networks: the intrachannel interactions between pulses in a single channel strong dispersion-managed transmission link. We calculate the interaction length between sets of two and three pulses as a function of the ratio of dissimilar peak powers of interacting solitons by means of a variational approach to the generalized nonlinear Schrodinger equation describing the evolution of optical soliton pulses. We find a maximum of this colliding length for specific values of pulse energies. The effect of higher-order perturbation terms, such as third-order dispersion, Raman scattering, and self-steepening, shows an enhancement of the interaction distance in a broad range of dispersion difference values. We conclude that the transmission characteristics of soliton trains may be improved by means of using specific values of unequal energies and taking into account higher-order correction terms.

Modeling of racetrack-resonator add-drop filters with arbitrary nonlinear directional couplers.

In this Letter we employ the general coupled-mode equations of the nonlinear directional coupler and demonstrate that the switching characteristics of prototypical nonlinear racetrack-resonator structures may differ considerably from those obtained when the standard, generally incorrect, coupled-mode equations are used.

MULTICHANNEL SOLITON COLLISIONS IN STRONGLY DISPERSION MANAGED WDM TRANSMISSION SYSTEMS

We study the collision-induced timing jitter of optical solitons in dispersion managed wavelength-division multiplexed communication systems. The work presented here is an extension of previous analyzes of two-pulse interactions to the multiple channel case. The numerical study is based on a system of ordinary differential equations obtained using a variational approach that models the evolution of the main parameters of the propagating pulses. We explain the mechanism associated with inter-channel interactions and study the evolution of multiplexed soliton trains and the resulting frequency shift induced jitter as the map strength is varied. The results obtained indicate a strong dependence of the frequency shifts on the position of the channel within the multiplex and the existence of patterns for the frequency shifts that depend on the parity of the number of channels.

Nonlinear effects induced in the normalized ion density in a linear trap system for a large ion cloud

In this work, we design, by means of a non-neutral plasma method, a linear trapping model for large ion clouds, which will become the core of an atomic clock. We first obtain the geometry and electromagnetic characteristics of the ion trap. We then perform a systematic analysis describing the main parameters of the ion cloud such as size, secular frequency, and ion number per unit length of temperature. The most appropriate operation point of the ion trap in a set of these specific parameters is evaluated, and a thorough discussion is performed about how minor perturbations introduced in these parameters affect, in a nonlinear response, the performance of the trapping system in sensibility, heating, and radiofrequency potential.

Interchannel collisions of strong dispersion-managed solitons with different energies in the presence of higher-order effects

We study the interaction properties of two-channel wavelength-division multiplexed strongly dispersion managed communication systems. By means of a variational approach to the Generalized Nonlinear Schrödinger Equation we obtain an ordinary differential equations model for the main parameters of the pulses including third-order dispersion, Raman scattering and self-steepening. We study the residual frequency shift for each channel after the collision between sets of two pulses as a function of the ratio of dissimilar peak powers in a broad range of dispersion difference values, concluding that the transmission characteristics improve by using specific values of unequal energies and considering higher-order correction terms.

Evaluación de competencias con metodologías de aprendizaje basado en proyectos

Tras dos cursos impartiendo una asignatura de aprendizaje basado en proyectos segun la metodologia Design Thinking en el Master en Ingenieria de Telecomunicacion de la Universidad de Vigo, los autores presentan su experiencia. Para ello se introduce la asignatura, con especial enfasis en la presentacion de las competencias que se desarrollan y evaluan segun dinamicas de Design Thinking. Posteriormente se expone el proceso de definicion de los grupos, su desarrollo y el procedimiento de evaluacion, en el que intervienen tanto docentes como alumnos siguiendo unas rubricas conocidas y publicadas al principio del curso. Tambien se analizan los resultados de la evaluacion de los trabajos paralelizando las valoraciones de profesores y alumnos, asi como la evaluacion de la satisfaccion que muestran los alumnos al participar en una experiencia de este tipo.

High-order micro-ring resonator transmission lines

We present recent results on high-order micro-ring resonator transmission lines for photonic signal processing. These include the analysis of newly put forward structures for the control of the group delay and the realization of transmission filters.