Inphotec Foundation organizes, every year, a program of seminars on topics of particular interest in the field of design and fabrication of photonic integrated devices. Talks are given by eminent Italian and foreign scientists and professors working in the area of photonic integration.
2019 Detailed program
Date: February 5, 2019 h. 15.30
Speaker: Prof. Giovanni Isella – LNESS, Dip. Di Fisica – Politecnico di Milano
Title: SiGe: a material platform for near- and mid-infrared photonics
Abstract: The recent interest towards chemical and biological sensing in the mid-infrared has fostered the need of high performance photonic integrated circuits operating in this spectral region. Germanium and silicon germanium alloys hold the potential to become the material platform of choice for waveguide-integrated near and mid-IR photonics, thanks to their wide transparency in this wavelength range. In this context epitaxy offers the unique possibility of avoiding silicon oxide cladding layers, which have limited transparency in the mid-IR, and of controlling the refractive index profile within the waveguide. In this framework, we are investigating Ge-rich SiGe as a promising material platform to develop passive optical devices operating in the mid-IR. The key elements of our approach are SiGe graded buffers, epitaxially grown on Si, where the linear grading of the Ge concentration from Si to Si1 xGex with a properly designed grading rate, allows a unique flexibility to engineer the refractive index profile of the structure. This ensures a strong confinement of the optical mode in the Ge-rich region and leads to the realization of SiGe waveguides and Mach-Zehnder interferometers operating between 5.5-8.5 μm with 2 dB/cm losses.
Moreover, heavily n-doped Ge has demonstrated a strong potential for the realization of plasmonic devices operating in the same spectral region, opening a path toward the integration of plasmonic and photonic devices within the same material platform.
As an additional example of the role played by epitaxial growth in Ge based near-IR photonics we will discuss the possibility of integrating Ge-based single photon detectors on Si substrates.
Bio of the speaker: Giovanni Isella graduated in Nuclear Engineering at the Politecnico di Milano, Italy in 1997 and holds a Ph.D. in Physics from the same institution. Between 2001 and 2002 G. I. has been working on the deposition and characterization of silicon-germanium heterostructures at the ETH-Zürich. In 2002 he obtained a faculty researcher position at the Physics Department of the Politecnico di Milano-Italy where he continued to work in the field of SiGe epitaxy. Since 2007 he is leading the SiGe epitaxy team at the laboratory for nanostructures epitaxy and spintronics on silicon (LNESS-Politecnico di Milano). In 2014 he became Associate Professor at Polimi and in 2017 the director of the laboratory for nanostructures, epitaxy and spintronics on silicon (LNESS). His current interests and expertise include: spin dynamics in Ge quantum wells, infrared light detection and modulation in SiGe heterostructures, Ge deposition on patterned substrates, integration of III-V semiconductors on Ge/Si, SiGe heterostructuctures for thermoelectric power generation. Since 2017 he is the director of the LNESS centre.
Speaker: Prof. Paolo Villoresi, Dipartimento di Ingegneria dell’Informazione, Università di Padova
Speaker: Prof. Giovanni Vallone, Dipartimento di Ingegneria dell’Informazione, Università di Padova
2018 Detailed program
Date: June 26, 2018 h. 9.30 am
Speaker: Dr. Romeo Bernini, IREA-CNR, Italy
Title: Integrated hollow core waveguides and devices for sensing applications
Abstract: Hollow core waveguides permit to confine the light in low refractive index media like as fluids (liquids or gases). This solution permits to realize innovative optical devices in which fluids can act as an optical material providing significantly enhanced performances and functionalities that cannot be achieved with conventional solid core waveguides. In particular, for sensing applications, the ability to confine both light and fluid under analysis within the same volume lead to a very high light-matter interaction with a strong improvement of the sensitivity. We show that single mode hollow core waveguides with low loss can be realized using antiresonant reflecting optical confinement (ARROW). These waveguides can be fabricated using full standard Silicon technology or hybrid Silicon-polymer processes. ARROW waveguides have been used in order to realize sensing platform for fluorescence measurements or label free sensing devices like Mach-Zehnder interferometers and ring resonators. This planar architecture holds the promise of high functionality and compactness towards a complete on-chip integrated sensing system.
Bio of the speaker: Dr. Romeo Bernini received his Laurea degree (summa cum laude) from the University of Naples Federico II, Naples, Italy, and his Ph.D. degree from the Second University of Naples, Aversa, Italy, in electronic engineering, in 1995 and 1999, respectively. He was a Research Fellow with the Second University of Naples in 2000. He is currently a senior researcher at the Institute for the electromagnetic sensing of the environment (IREA) of the Italian National Research council (CNR). His research fields are optoelectronic devices and sensors, microfluidic and optofluidic devices and fiber optic sensors. He has authored or coauthored more than 90 papers published in various international journals. He is a reviewer for several technical journals. He holds one international and two national patents on fiber optic sensors.
Date: September 5, 2018 h. 2:30 pm
Speaker: Prof. Jonathan Klamkin, University of California Santa Barbara
Title: Integrated Photonics Technologies: Laser Integration for Silicon Photonics by Hybrid Integration and Direct Heteroepitaxy
Abstract: This talk will describe developments in integrated photonic technologies at the University of California Santa Barbara with emphasis on silicon photonics, indium phosphide, hybrid integration, and III-V on silicon heteroepitaxy. The 3D hybrid integration technique is based on flip-chip bonding of surface-emitting indium phosphide devices that couple to silicon waveguides through surface grating couplers. III-V on silicon heteroepitaxy instead relies on the direct growth of direct bandgap materials on silicon and emphasizes defect reduction techniques as well as defect tolerant laser structures.
Date: September 6, 2018 h. 2:30 pm
Speaker: Prof. Jonathan Klamkin, University of California Santa Barbara
Title: Integrated Photonics Applications: Microwave Photonics, Free Space Communications, and Sensing
Abstract: Applications for integrated photonic technologies include telecommunications, data center communications, microwave photonics, free space communications, lidar, and remote sensing. This talk will emphasize applications where photonic integrated circuits (PICs) dramatically reduce system cost, size, weight and power (CSWaP) while improving performance and reliability. These include integrated optical beam forming networks for extreme high frequency communications and phase arrays, lidar for 3D mapping, free space laser communications, and remote earth science sensing lidar.
Bio of the speaker: Jonathan Klamkin is a professor at the University of California Santa Barbara where he leads a group of ~18 researchers conducting pioneering research in integrated photonic technologies. Previously he held positions at MIT Lincoln Laboratory, the Scuola Superiore Sant’Anna, Pisa, Italy, and Boston University. He is a Chair for the 2018 Integrated Photonics Research, Silicon and Nanophotonics Conference, Vice-Chair for the Microwave Theory and Techniques Society Subcommittee on Microwave Photonics, Associate Editor for Photonics Technology Letters and Steering Committee Member for the Journal of Lightwave Technology. Prof. Klamkin is the recipient of a NASA Early Career Faculty Award and the DARPA Young Faculty Award. He or his students have won best paper awards at the Conference on Optoelectronic and Microelectronic Materials and Devices Conference (COMMAD), the Microwave Photonics Conference (MWP), and the Asia Communications and Photonics Conference (ACP). He has published more than 160 papers, and holds 1 patent and 3 pending patents. Group website: http://integratedphotonics.ece.ucsb.edu/