Fabrication of an optical 2×4 reconfigurable switch, electrically controlled by a FPGA module.
The prototype is to be considered as a proof of concept for the MOS active-matrix approach to the metamaterial configuration.
Is it possible to define a low-cost process for the fabrication of photonic programmable switches?
The result obtained in the end of this project has the potential to contribute for improving the digital competence of the future society, as the optical computing paradigm as several major advantages like low power, low junction heating, high speed, dynamically scalable and reconfigurable into smaller or larger networks or topologies, massive parallel computing ability and AI applications.
THE IDEA
An MOS structure (Au/ITO/SiNx/a-Si:H) can be used, in a process very similar to the channel creation in a standard TFT, to electrically and dynamically create a localized accumulation of charge and a corresponding local alteration of the a-Si:H refractive index.
A matrix distribution of these MOS structures, controlled by programmable FPGA hardware on the upper surface of an a-Si:H MMI, allows the dynamical electrical configuration of the material’s refractive index.
Each MOS is treated just like a pixel and controlled by an active-matrix scheme. A previous definition of the voltage images, optimized by joining FDTD simulations and a machine learning approach, permits the switching operation and to control over the output channels, allowing the generation of completely independent functions, with real-time reconfigurability controlled by FPGA hardware systems.
FUNDING
ASER-META
Activity years:
2023 – 2024
Funding body:
Fundação para a Ciência e a Tecnologia, I.P
Reference:
2022.07694.PTDC
Host Institution:
Instituto Superior de Engenharia de Lisboa (ISEL)
Integrated photonics represents an unmatched opportunity for implementing an unconstrained variety of programmable functions. It is considered as the key technology for future applications in optical transceivers, ASIC integration, 3D imaging and sensing device in biomedics or light detection and ranging (LIDAR) systems for automotive industry.
Nevertheless, industry has failed, until now, in demonstrating large-scale deployment of Photonics Integrated Circuits (PICs) achieving an economy of scale like those attained by Application Specific Integrated Circuits (ASICs) in microelectronics. Anyway, there is still a great expectation for this roadmap and great interest has been posed, among others, in the application of photonic switching structures, aiming to the development of programmable devices for optical data processing.
The switching operation in the devices proposed and described in literature are typically based on electro-optical and thermo-optical mechanisms. Induced phase changes have also been demonstrated to allow reconfigurable bistable functions. Whichever the supporting physical effect, the switching mechanism is based on fine tuning the refractive index of suitable materials incorporated in the device. An interesting approach, recently reported, uses a nanostructured material geometry to create an arbitrary distribution of the refractive index values, allowing power splitting with arbitrary input and output directions. The integration of subwavelength-structured metasurfaces and metamaterials on the standard optical waveguides is gradually reshaping the landscape of photonic integrated circuits, giving rise to numerous meta-waveguides with unprecedented control capabilities.
Within this context, the application of machine learning techniques allows the project of metamaterial-based devices that can be fabricated in the traditional semiconductor process. At the same time, a novel approach, based on waveguide with multi-micron dimension, allowing a better polarization and process tolerance management, has been recently proposed, and the fabrication tolerance induced by a multi-micron dimension paves the way to a new efficient use of hydrogenated amorphous silicon (a-Si:H) deposited with the PECVD method. PECVD is the technique that enables the low-cost fabrication (and commercialization) of large area flat panel displays, where each pixel is controlled individually by a single a-Si:H Thin Film Transistor (TFT) in an active-matrix configuration.
The idea hereby proposed is based on joining these three characteristics (metamaterial-based devices, PECVD materials and Active-Matrix control) to develop a programmable switching function on a MMI structure with multiple input/output ports. Due to its intrinsic low conductivity, a-Si:H lateral transport effects are naturally confined to the region of the charge source. So, an MOS structure (Au/ITO/SiNx/a-Si:H) can be used, in a process very similar to the channel creation in a standard TFT, to electrically and dynamically create a localized accumulation of charge and a corresponding local alteration of the a-Si:H refractive index.
A matrix distribution of these MOS structures, controlled by programmable FPGA hardware on the upper surface of an a-Si:H MMI, allows the dynamical electrical configuration of the material’s refractive index. Each MOS is treated just like a pixel and controlled by an active-matrix scheme. A previous definition of the voltage images, optimized by joining FDTD simulations and a machine learning approach, permits the switching operation and to control over the output channels, allowing the generation of completely independent functions, with real-time reconfigurability controlled by FPGA hardware systems.
RESEARCHERS
Alessandro Fantoni
Alessandro Fantoni
Alessandro Fantoni was born in Rome (Italy) in 1966. He received a university degree in applied mathematics from the University of Camerino, Italy (1992), and a PhD in Material Engineering/Micro and Optoelectronics from the New University of Lisbon, Portugal (1999). Presently he is a Coordinator Professor at the Electronics, Telecommunications and Computer Department of the Engineering Institute of Lisbon and he is a member of the UNINOVA-CTS research centre in Caparica (Portugal).
Daniel Gonçalves Pita Santos de Almeida, completed his Master’s Degree in Electronics and Telecommunications Engineering in 2018 at the Instituto Superior de Engenharia de Lisboa of the Polytechnic Institute of Lisbon and his Bachelor’s Degree in Electronics and Telecommunications and Computer Engineering in 2014 at the same institution. Attends the PhD in Electrical and Computer Engineering at the Faculty of Science and Technology, Universidade Nova de Lisboa since September 8, 2020, having at the date of writing of this document an average of 16 values. Published 2 articles in peer-reviewed journals, one as main author and the other as co-author. Participated in 3 scientific events. Has received 1 award. Participates and/or has participated as a PhD Grant Holder in 3 projects. Works in the areas of Engineering Sciences and Technologies with emphasis on Electrical, Electronic and Computer Engineering. In his curriculum Vitae the most frequent terms in the contextualization of scientific, technological and artistic-cultural production are: Photonic Devices; Optical Waveguides; Biosensors; Signal Conditioning; Signal Processing; Analog, Digital and Mixed-Signal Circuits; Multi-Mode Interferometers (MMIs); Biomedical Devices; Computer Design, Modeling and Simulation of Electronic and Photonic Devices; Amorphous Silicon Compounds; Plasmonic Sensors; Photonic and Optical Sensors; Optical Fiber
Luís Miguel Tavares Fernandes. D. in Materials Engineering in 2009 from the New University of Lisbon Faculty of Sciences and Technology and Graduation in Physical Engineering and Materials, Physics Engineering branch in 1995 from the New University of Lisbon Faculty of Sciences and Technology. He is an Adjunct Professor at Instituto Politécnico de Lisboa Instituto Superior de Engenharia de Lisboa. He has published 182 articles in peer-reviewed journals. He has published 2 book(s). He has supervised 2 MSc dissertations and co-supervised 1. He participates and/or has participated as an Investigator in 15 projects and as the Principal Investigator in 5 projects. He works in the area(s) of Engineering Sciences and Technologies with emphasis on Materials Engineering and Engineering Sciences and Technologies with emphasis on Electrical Engineering, Electronics and Informatics. In his curriculum Vitae Science the most frequent terms in the contextualization of scientific, technological and artistic-cultural production are: Electrical Engineering – Electronics and Computers; Electrical and Computer Engineering – Electronics; Microelectronics; Electrical Systems and Energy; Amorphous Silicon; Photonics; Analog Electronics; Digital Electronics; Embeded Systems; Energy; Materials Science and Engineering; Physics.
Maria Manuela Carvalho Vieira é Licenciada em Física (Investigação Científica: Espectroscopia Nuclear) pela Faculdade de Ciências de Lisboa, Mestre em Física do Estado Sólido (Microelectrónica), possui Doutoramento em Ciência dos Materiais (Materiais Semicondutores) e é detentora do título de Agregado (Ramo de Engenharia Electrotécnica, grupo de disciplinas de Electrónica) pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa.
Maria Manuela Carvalho Vieira has a degree in Physics (Scientific Research: Nuclear Spectroscopy) from the Faculdade de Ciências de Lisboa, a Master in Solid State Physics (Microelectronics), a PhD in Materials Science (Semiconductor Materials) and is Aggregated (Branch of Electrical Engineering, subject group of Electronics) from the Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa.
Professor at ISEL since 1975 where she is Principal Coordinator Jubilee. She was responsible for all the curricular units she taught and supervised internships, masters, doctoral and post-doctoral courses. She has taken part in juries of competitive examinations for assistant professors, co-ordinators and principal co-ordinators, in academic examinations for master’s degrees, doctorates and aggregation, and in competitive examinations for scientific and pedagogical aptitude tests. She has taught university extension courses at the FCT-UNL where she is an Invited Associate Professor. She assumed the positions of Electronics Section Coordinator, Head of the Electronics Disciplinary Group, Chair of the Department of Electronics, Telecommunications and Computers, Head of the Scientific Area of Electronics, Telecommunications and Computers, Vice-President of ISEL, and President of the Scientific-Technical Council of ISEL. As Vice-President he coordinated the Assessment and Coordination Committee of the Assessment Process, the Committee for Drafting the Regulations of the Scientific-Technical Council, was member of the Committee for the Definition of the Strategic Plan of ISEL, the Committee for Quality Assessment and the Parity Committee of ISEL.
Maria Manuela Carvalho Vieira has a degree in Physics (Scientific Research: Nuclear Spectroscopy) from the Faculdade de Ciências de Lisboa, a Master in Solid State Physics (Microelectronics), a PhD in Materials Science (Semiconductor Materials) and is Aggregated (Branch of Electrical Engineering, subject group of Electronics) from the Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa.
Professor at ISEL since 1975 where she is Principal Coordinator Jubilee. She was responsible for all the curricular units she taught and supervised internships, masters, doctoral and post-doctoral courses. She has taken part in juries of competitive examinations for assistant professors, co-ordinators and principal co-ordinators, in academic examinations for master’s degrees, doctorates and aggregation, and in competitive examinations for scientific and pedagogical aptitude tests. She has taught university extension courses at the FCT-UNL where she is an Invited Associate Professor. She assumed the positions of Electronics Section Coordinator, Head of the Electronics Disciplinary Group, Chair of the Department of Electronics, Telecommunications and Computers, Head of the Scientific Area of Electronics, Telecommunications and Computers, Vice-President of ISEL, and President of the Scientific-Technical Council of ISEL. As Vice-President he coordinated the Assessment and Coordination Committee of the Assessment Process, the Committee for Drafting the Regulations of the Scientific-Technical Council, was member of the Committee for the Definition of the Strategic Plan of ISEL, the Committee for Quality Assessment and the Parity Committee of ISEL.
Paula Louro graduated in Technological Physics (1992) from the Faculty of Sciences of the University of Lisbon. She obtained a Master’s degree in Materials Engineering in 1995 from the Faculty of Sciences and Technology of the New University of Lisbon and a PhD in Electrical and Computer Engineering in 2007 from the Faculty of Sciences and Technology of the New University of Lisbon. She holds since 2015 the title of Aggregate in Electrical and Computer Engineering by the Faculty of Sciences and Technology of the New University of Lisbon.
She is currently Coordinating Professor with Aggregation in the Department of Electronic Engineering, Telecommunications and Computers, where she teaches since 1998. She teaches Electronics and Optoelectronics in the Electronic, Telecommunications and Computer Engineering courses and in the Masters in Electronics and Telecommunications Engineering. His main scientific interests focus on optoelectronics, with emphasis on the characterization and development of semiconductor materials and devices in applications ranging from unguided optical communication to biosensors. Recently, she has coordinated several research projects in the area of visible light communication. She is author and co-author of numerous publications in international journals and international peer-reviewed conference proceedings, indexed in WoS. She is an integrated member since 2007 of the FCT funded research centre: Centre for Technologies and Systems.
