Molding the flow of light through subwavelength devices

Patterning of subwavelength scale structures onto dielectrics allows engineering the local refractive index, dispersion and anisotropy of materials, thus opening new design possibilities which give unprecedented control of light shape in photonic integrated circuits. In this talk we will present an overview of our recent advances in subwavelength based devices of practical importance including fiber-chip couplers, ultra-broadband MMI devices, mode and polarization multiplexers and bragg deflectors.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Varactor-Tuned Dual-Mode Frequency Discriminator for Instantaneous Frequency Measurements

In this paper a novel varactor-tuned frequency discriminator that makes use of two tunable dual-mode microstrip resonators is demonstrated which doubles the discriminator tuning bandwidth. To prove its validity a prototype of the tunable dual-mode microstrip resonator is manufactured and the measured results are used to study the frequency discriminator response. This new approach can cover almost an octave of frequency range from 1.05 to 2 GHz with a sensitivity of 45 V/GHz and 21 V/GHz for the first and second mode, respectively.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Quantum work statistics, Loschmidt echo and information scrambling

A universal relation is established between the quantum work probability distribution of an isolated driven quantum system and the Loschmidt echo dynamics of a two-mode squeezed state. When the initial density matrix is canonical, the Loschmidt echo of the purified double thermofield state provides a direct measure of information scrambling and can be related to the analytic continuation of the partition function. Information scrambling is then described by the quantum work statistics associated with the time-reversal operation on a single copy, associated with the sudden negation of the system Hamiltonian.Comment: 6 pages, 1 figure, published versio

Comparing the fundamental limit of detection for interferometric and resonant biosensors with coherent phase read-out

We compare the limit of detection of coherently interrograted photonic biosensors, using both interferometric and resonant architectures.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Discriminador de frecuencia basado en resonadores “dual-mode” sintonizables

Presentado en el XXVIII Simposium Nacional de la Unin Cientfica Internacional de Radio. URSI 2013, Santiago de Compostela, 11 al 13 de septiembre de 2013.In this paper a novel varactor-tuned frequency discriminator that makes use of two tunable dual-mode microstrip resonators is demonstrated. In this circuit, the two tuned modes of the resonators are used independently to cover different frequency ranges, potentially doubling the tuning frequency range of the classic approach. To prove its validity a prototype of the tunable dual-mode microstrip resonator is manufactured and the measured results are used to study the frequency discriminator response. This new approach can cover almost an octave of frequency range from 1.05 to 2 GHz with a sensitivity of 45 V/GHz and 21 V/GHz for the first and second mode, respectively.Este trabajo ha sido financiado por la Consejería de Ciencia, Innovación y Empresa de la Junta de Andalucía bajo los proyectos P09-TIC-5268,MUPHY y una beca FPDI(780008),y por la empresa AT4Wireless bajo el contrato 8.06/5.59.3165. Universidad de Málaga,Campus de Excelencia Internacional Andalucía Tec

Towards photonic biosensing using a three-port mach-zehnder interferometer in a silicon nitride platform

Integrated photonics enables sensitive and label-free optical biosensors for the detection of chemical and biological substances and is therefore promising for future lab-on-chip solutions. In this article we present our current development of silicon nitride based integrated photonic biosensing devices working at telecom wavelengths. Our approach of three-port based interferometric sensing circumvents the issues of conventional Mach-Zehnder interferometers, providing a constant sensitivity, and allowing to use a fixed wavelength sensing scheme. Preliminary experimental results show that the fabricated devices work as expected from simulations.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

High performance and small footprint spot size converters based on SWG metamaterial lenses

Spot size converters with high expansion ratio are required in a variety of situations. This is the case of non-focusing Silicon on Insulator (SOI) fiber-to-chip grating couplers, which typically require long adiabatic tapers (Ltaper >100μm) from the narrow single-mode waveguides (WSi-wire ~ 500nm) to the wide grating region (Wgrating ~ 15μm). Here, we explore the potential of subwavelength grating (SWG) dielectric metamaterials to implement integrated GRaded INdex (GRIN) lenses to expand the mode field. Our designs achieve the desired Beam Expansion (BE) with insertion losses below 1dB over a distance of only LBE ~ 17μm.Ministerio de Economía y Competitividad, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad (cofinanciado FEDER), (TEC2016-80718-R); Universidad de Málaga. Ministerio de Educación, Cultura y Deporte (MECD) (FPU16/06121); Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Receptor coherente integrado ‘colorless’ de gran margen dinámico basado en un acoplador a 120º

Un receptor ‘colorless’ requerirá en su banda de operación de un elevado rechazo en modo común CMRR para reducir eficientemente la interferencia en banda base ocasionada por los canales colindantes al detectado y conseguir un mayor rango dinámico de operación. La obtención de un elevado CMRR se ve imposibilitada en la práctica en el receptor convencional a 90º (basado aquí en un MMI 2x4) por los inevitables desbalanceos, ya sea por operar lejos de su frecuencia de diseño o por las tolerancias presentes en su proceso de fabricación. En esta contribución se propone como alternativa un esquema coherente basado en un acoplador a 120º (implementado con un MMI 2x3), capaz simultáneamente de demodular sin distorsión las componentes IQ de un canal específico y ofrecer un elevado CMRR en una amplia banda de operación. Esto es posible desde la realización de una sencilla operación lineal desde un circuito analógico calibrado, pudiendo prescindir así de los algoritmos de ortogonalización (GSOP) necesarios en el receptor convencional a 90º para resolver sus desbalanceos. Los resultados numéricos muestran que en un escenario realista de fabricación nuestra propuesta es una interesante alternativa al receptor convencional. Así, específicamente, para una recepción 'colorless' de 80 canales modulados a 56 Gbps bajo 16-QAM, es capaz de ofrecer un rango dinámico de 21 dB frente a los 8 dB del receptor convencional a 90ºUniversidad de Málaga Campus de Excelencia Internacional Andalucía Tech. CEIC de Andalucía (P09-TIC-5268), C.I.C.Y.T. (TEC2009-10152), MIRTHE ICT-2009-5 nº 25798

Optimizing panchromatic image change detection based on change index multiband image analysis

This work proposes an optimization of a semi-supervised Change Detection methodology based on a combination of Change Indices (CI) derived from an image multitemporal data set. For this purpose, SPOT 5 Panchromatic images with 2.5 m spatial resolution have been used, from which three Change Indices have been calculated. Two of them are usually known indices; however the third one has been derived considering the Kullbak-Leibler divergence. Then, these three indices have been combined forming a multiband image that has been used in as input for a Support Vector Machine (SVM) classifier where four different discriminant functions have been tested in order to differentiate between change and no_change categories. The performance of the suggested procedure has been assessed applying different quality measures, reaching in each case highly satisfactory values. These results have demonstrated that the simultaneous combination of basic change indices with others more sophisticated like the Kullback-Leibler distance, and the application of non-parametric discriminant functions like those employees in the SVM method, allows solving efficiently a change detection problem

Diffractive sidewall grating coupler: towards 2D free-space optics on chip.

Silicon photonics has been the subject of intense research efforts. In order to implement complex integrated silicon photonic devices and systems, a wide range of robust building blocks is needed. Waveguide couplers are fundamental devices in integrated optics, enabling different functionalities such as power dividers, spot-size converters, coherent hybrids and fiber-chip coupling interfaces, to name a few. In this work we propose a new type of nanophotonic coupler based on sidewall grating (SIGRA) concept. SIGRAs have been used in the Bragg regime, for filtering applications, as well as in the sub-wavelength regime in multimode interference (MMI) couplers. However, the use of SIGRAs in the radiation regime has been very limited. Specifically, a coarse wavelength division multiplexer was proposed and experimentally validated. In this work we study the use of SIGRAs in the diffractive regime as a mean to couple the light between a silicon wire waveguide mode and a continuum of slab waveguide modes. We also propose an original technique for designing SIGRA based couplers, enabling the synthesis of arbitrary radiation field profile by Floquet- Bloch analysis of individual diffracting elements while substantially alleviating computational load. Results are further validated by 3D FDTD simulations which confirm that the radiated field profile closely matches the target design field.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec