Reducing polarization-dependent loss of silicon-on-insulator fiber to chip grating couplers

For many telecommunication applications, low polarization-dependent loss (PDL) operation is mandatory. On the silicon-on-insulator photonic wire platform, this can be achieved using polarization diversity configurations. However, as we show here, when using two-dimensional grating couplers for near vertical fiber input and output, the low PDL bandwidth is limited. We propose and demonstrate the use of a phase shifter in one of the arms of the polarization diversity circuit to effectively reduce PDL (0.15-dB PDL is shown) and increase the low PDL bandwidth

Photonic Reflectometer on Silicon-on-Insulator

A photonic reflectometer on Silicon-on-Insulator is designed and experimentally characterized. The reflectometer is a six-port device, composed of multimode interference couplers (MMIs). We propose a design approach for high-performance MMIs, and describe a minimum phase technique to characterize both the MMIs and the reflectometer. Furthermore, a single-etch fibre-to-chip grating coupler is demonstrated

Bringing Optical Communications to the General Public: an Innovative Bachelor Thesis

The United Nations “International year of light 2015” strives to highlight the importance of optical technologies in our everyday lives. Fibre optic communication is one such technology: the growth of internet and its associated services are enabled by the vast transmission bandwidth provided by optical networks. However, the general public is not well aware of the optical and electronic fundamentals of the underlying transmission systems. Here we present the development of a bachelor thesis in Telecommunication Engineering in which a small-scale fibre-optic link is built and the electronics required to transmit music over this link are implemented. The resulting system demonstrates, in a very intuitive way, how information is transmitted over an optical fibre.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Colorless devices and reception techniques for polarization multiplexed communications

Future optical networks call for flexible, high performance and low cost coherent optical receivers. We present here several advances towards such receivers, including integrated optical couplers with ultra-broad bandwidth, as well as novel reception techniques and architectures that will enable high performance coherent reception without filtering and polarization splitting elements.Universidad de Málaga - Campus de Excelencia Internacional Andalucía Tech. Spanish Ministry of Science under project TEC2013-46917-C2-1-

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

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

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

Estudio comparativo de biosensors coherentes basados en estructuras interferométricas y resonantes

La gran mayoría de los biosensores fotónicos de campo evanescente se basan en arquitecturas interferométricas o resonantes. La determinación analítica del límite de detección (LOD) alcanzable con estas arquitecturas es muy importante. Sin embargo, hasta donde los autores conocen, no existe un marco común que permita establecer una comparación justa entre ambas alternativas en términos de su LOD intrínseca. En este artículo desarrollaremos un modelo sistémico para biosensores fotónicos, que incluye las posibles pérdidas ópticas y el ruido térmico, a partir de las cuales se puede comparar el LOD intrínseco de ambas arquitecturas. Los resultados obtenidos muestran que la arquitectura interferométrica debe ser la opción preferente para todos aquellos casos en los que la cantidad disponible de analito no es un recurso limitadoUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Este trabajo ha sido parcialmente financiado por el proyecto TEC2016-80718-R del Ministerio de Economía y Competitividad (cofinanciado FEDER) y por la acción Marie Skłodowska-Curie 713721