Gap solitons and symmetry breaking in parity-time symmetric microring CROWs

The propagation properties of optical fields in linear and nonlinear parity-time symmetric microring coupled resonator optical waveguides are studied. The effects described include the existence of symmetry breaking thresholds, the propagation of gap solitons in nonlinear transmission lines and the existence of quasi stable propagation regimes outside the broken symmetry regions.Comment: Final Versio

A simple method for estimating the fractal dimension from digital images: The compression dimension

Producción CientíficaThe fractal structure of real world objects is often analyzed using digital images. In this context, the compression fractal dimension is put forward. It provides a simple method for the direct estimation of the dimension of fractals stored as digital image files. The computational scheme can be implemented using readily available free software. Its simplicity also makes it very interesting for introductory elaborations of basic concepts of fractal geometry, complexity, and information theory. A test of the computational scheme using limited-quality images of well-defined fractal sets obtained from the Internet and free software has been performed. Also, a systematic evaluation of the proposed method using computer generated images of the Weierstrass cosine function shows an accuracy comparable to those of the methods most commonly used to estimate the dimension of fractal data sequences applied to the same test problem.Junta de Castilla y León Regional Grant VA089U1

Corner reflectors: fractal analysis and integrated single-photon sources

In this work, the properties of the radiation emitted by a corner reflector with an electric dipole feeder are analyzed in the optical domain where the distance between the dipole and the corner apex can be large in terms of the optical wavelength. A comprehensive study of the fractal properties of the radiated intensity patterns is presented. The use of this setup for the realization of single-photon sources in photonic integrated circuits is also put forward and a detailed study of the emission properties of the device and its optimal configurations is presented

Phase asymmetry effect in longitudinal offset coupled resonator optical waveguides

We show that the implementation of the longitudinal displacement technique for adjusting the coupling coefficients in microring waveguides is subject to a phase asymmetry effect. This issue is shown to substantially alter the system response in apodized filters and cannot be ignored in the design stage