Simulations of vertically-coupled microdisk-resonators by 3-D vectorial coupled mode theory

Fully vectorial 3D frequency-domain simulations of vertically coupled integrated-optical microdisk-resonators are described. The 'rigorous' coupled mode theory model combines numerically computed bend modes of the cavity disk and guided modes of the straight bus waveguides

Design of arbitrary optical filters in silicon-on-insulator using evanescently-coupled Bragg gratings

Spectral filters are experiencing an increasing demand in several applications of the silicon- on-insulator (SOI) platform. Many works have demonstrated that arbitrary frequency responses can be synthesized by apodizing the coupling coefficient profile of an integrated Bragg grating. However, the high index contrast of the SOI platform hinders their practical implementation, due to the difficulty of achieving the precise control required in the Bragg strength. In this paper, we propose the implementation of spectral filters using an architecture based on placing loading segments within the evanescent field region of a photonic wire waveguide. The Bragg coupling coefficient can be accurately controlled by simply moving the segments away from, or closer to, the waveguide core. The layerpeeling algorithm, in conjunction with a Floquet-Bloch modal analysis, allows to determine the spatial distribution of the segments that synthesizes the desired spectrum. The proposed topology is verified by designing a filter with five arbitrary passbands.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A comparison between different propagative schemes for the simulation of tapered step index slab waveguides

The performance and accuracy of a number of propagative algorithms are compared for the simulation of tapered high contrast step index slab waveguides. The considered methods include paraxial as well as nonparaxial formulations of optical field propagation. In particular attention is paid to the validity of the paraxial approximation. To test the internal consistency of the various methods the property of reciprocity is verified and it is shown that for the paraxial algorithms the reciprocity can only be fulfilled if the paraxial approximation of the power flux expression using the Poynting vector is considered. Finally, modeling results are compared with measured fiber coupling losses for an experimentally realized taper structure

Enhanced sensitivity subwavelength grating waveguides for silicon photonics sensing applications

OSA (Optical Society of America)In this work we will review the enormous potential of subwavelength grating waveguides for sensing applications in the near and mid-infrared bands, demonstrating the capability to engineer the mode profile to maximize the light-matter interaction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

High performance silicon photonic devices based on practical metamaterials

Robert Halir, et al., "High performance silicon photonic devices based on practical metamaterials," OECC/PSC, 7-12 July 2019, Fukuoka (Japan)Subwavelength grating metamaterials are enabling a new generation of high-performance silicon photonic devices. Here we discuss the fundamental physics along with some of the latest advances in this rapidly expanding field.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Ministerio de Economía y Competitividad, Programa Estatal de Investigación Orientada a los Retos de la Sociedad (cofinanciado FEDER) – TEC2016-80718-R, TEC2015-71127-C2-1-R (FPI BES-2016-077798) and IJCI-2016-30484; Community of Madrid – S2018/NMT-4326, Marie Sklodowska-Curie –734331, Czech Science Foundation – 1900062

Customized spectral filters using cladding-modulated Bragg gratings in silicon waveguides.

Funding: Ministerio de Economía y Competitividad (PID2019-106747RB-I00); Ministerio de Educación, Cultura y Deporte (FPU16/03401, FPU16/06762, FPU17/00638); Junta de Andalucía (P18-RT-1453, P18-RT-793, UMA18-FEDERJA-219); Universidad de Málaga; National Research Council Canada (CSTIP grant #HTSN210); Grantová Agentura České Republiky (19-00062S).Waveguide Bragg gratings are expected to play an important role in diverse applications of photonic integrated circuits. Here, we present our latest progress in implementing Bragg filters with a customized spectral response in the silicon-on-insulator platform. Our filter comprises a silicon waveguide with an array of Bragg segments placed aside. The waveguide core is designed to have a reduced mode confinement, which enables an accurate control of the grating strength via modulation of the Bragg segment separation distance and allows for minimum feature sizes compatible with deep-UV lithography (>100 nm). Our design strategy is experimentally validated by demonstrating a filter with 20 non-uniformly spaced notches in the transmittance spectrum. Palabras clave: Silicon photonics, Bragg gratings, spectral filters.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Diseño de filtros ópticos integrados con respuesta espectral arbitraria en tecnología de silicio sobre aislante

Silicon photonics is one of the most promising technologies nowadays, with myriads of potential applications in communications and sensing. Many of these applications require spectral filters synthesizing arbitrary frequency responses. However, the high refractive index contrast of the platform makes the design quite challenging. In this work, we propose to use a Bragg grating topology based on a silicon waveguide with evanescently coupled loading segments whose separation can be changed to accurately modify its strength. By using the layer-peeling algorithm to find the Bragg apodization profile, a filter with 20 transmission peaks located at arbitrary wavelengths has been designed.Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad (MINECO) en el marco del proyecto TEC2016-80718-R, por el Ministerio de Educación, Cultura y Deporte (MECD) a través de una ayuda con referencia FPU17/00638 y por la Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech

Design of subwavelength grating metamaterial waveguides for communications and sensing applications

In this work we will cover some of our recent advances in the design of state-of-the-art silicon photonic devices based on all-dielectric subwavelength grating (SWG) metamaterials. Specifically, we will focus on the design of tilted SWG waveguides, integrated anisotropic SWG lenses, spectral filters based on SWGs and SWG structures for evanescent field sensing.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Engineering sub-wavelength silicon waveguides for sensing applications in the near-infrared and mid-infrared band

Silicon photonics is one of the most promising candidates to achieve lab-on-a-chip systems. Making use of the evanescent-field sensing principle, it is possible to determine the presence and concentration of substances by simply measuring the variation produced by the light- matter interaction with the real part of the mode effective index (in the near infrared band), or with its imaginary part in a specific range of wavelengths (in the mid-infrared band). Regardless of which is the operating wavelength range, to maximize the device sensitivity it is essential to select the proper sensing waveguide. In this work we will review the potential of diffractionless sub-wavelength grating waveguides (SWG) for sensing applications by demonstrating its powerful capability to engineer the spatial distribution of the mode profile, and thereby to maximize the light-matter interaction. Among other things, we will demonstrate that the SWG waveguide dimensions used until now in the near-infrared are not optimal for sensing applications. In the mid-infrared band, due to the unacceptable losses of silicon dioxide for wavelengths longer than 4 μm, an additional effort is required to provide a more convenient platform for the development of future applications. In this sense, we will also show our recent progresses in the development of a new platform, the suspended silicon waveguide with subwavelength metamaterial cladding. A complete set of elemental building blocks capable of covering the full transparency window of silicon (λ < ∼8.5 μm) will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Subwavelength metamaterial for communications and sensing

Silicon photonics is considered a breakthrough technology with strong impact in areas as diverse as data center interconnection, high performance computing, the deployment of 5G future communication systems or lab-on-a-chip sensors. The emergence of sub-wavelength grating waveguides (SWG) has been fundamental to achieve advanced devices with unprecedented performance in integrated optics. In this talk we will focus on our recent progress in designing sub-wavelength engineered devices like ultra-broadband mode (de)multiplexers and converters [1], ultra-narrowband Bragg filters [2], sensing waveguides with enhanced sensitivity [3], or suspended silicon mid-infrared waveguides capable of covering the full transparency window of silicon [4], among other. This work was supported by the Ministerio de Economía y Competitividad, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad (Proyecto TEC2016-80718-R), and the Universidad de Málaga (Campus de Excelencia Internacional Andalucía Tech).Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech