Day 1 :
- Optics
Session Introduction
Mikhail E Belkin
Prof. Dr. of Sciences, MIREA – Russian Technological University, Moscow, Russia
Title: Investigating Versatile Computer-Aided Design of Microwave-Bandwidth Photonic Devices
Biography:
Prof. Dr. Mikhail E. Belkin received an engineering degree in radio and television from Moscow Institute of Telecommunications, in 1971, Ph. D. degree in telecommunication and electronic engineering from Moscow Technical University of Telecommunications and Informatics, in 1996, and Sc. D. degree in photonics and optical communications from Moscow State Technical University of Radio-Engineering, Electronics and Automation, in 2007. He has written more than 250 scientific works in English and Russian. The major current R&D fields are fiber-optic devices and systems, microwave photonics, photonic ICs, incoming cellular communication networks, computer-aided design.
Abstract:
Introduction: Microwave photonics (MWP) is an interdisciplinary scientific and technological field that combines the microwave electronics and photonics worlds [1-3]. Emerging applications for information and communication networks (ICN) of fiber-wireless architecture, sub-terahertz wireless systems, radars, and electronic warfare systems indicate that MWP is set to be a subject of increasing importance. In a typical arrangement of MWP-based radio-frequency receiver, a photonic circuit is inserted between two microwave electronic chains (Fig. 1). For direct and inverse transfers of microwave and optical signals there are two interfacing units at their bounds: electrical-to-optical (E/O) and optical-to-electrical (O/E) converters. Between the interfaces there are various photonics units for processing microwave signals in optical domain.
Statement of the Problem: The developer of new MWP devices and systems is facing a problem of choosing an appropriate computer tool for their modeling and design, but is forced to use means of several computer-aided design (CAD) tools because the existing optical and optoelectronic CAD tools (OE-CAD) are not as developed as compared with the CAD tools intended for modeling of microwave devices (E-CAD) For example, well-known OE-CAD allows executing in precision manner the modeling of a fiber-optic link with detailed study of optical units’ characteristics, but RF and especially microwave and millimeter-wave functional units are represented without paying attention to specialties of microwave band. On the other hand, operating at symbolic level modern high-power microwave E-CAD tool simply and with high precision solves this problem but there are completely no models of active optoelectronic components in the libraries [4, 5].
In the paper, a number of the E-CAD models for active and passive MWP elements, such as semiconductor laser, photodetector, optical modulator, multichannel reflecting Bragg grating, and for some MWP devices are presented and experimentally validated.
Alessandro Bile
Sapienza University of Rome, Italy
Title: Solitonic neuromorphic hardware for pattern recognition and episodic memorization
Biography:
Alessandro Bile graduated in physics (2019) at the “Sapienza” University of Rome as part of the VIRGO experiment and in Electronic Music from the “Santa Cecilia” Conservatory (2018). In 2019 he entered the Electromagnetism PhD at the "Sapienza". He deals with mathematical modeling and design of intelligent hardware systems operating in the optics domain. Between 2019 and 2022 he signed two contracts with Sapienza on the European project "Collection Care" and on "Intelligent optical systems for the recognition and the sanitization of pathological microorganisms and nano-organisms" project. He also applies artificial intelligence techniques to the microclimate of cultural heritage to provide useful forecasts for the conservation of artistic artefacts. He was awarded the "Avvio alla Ricerca" funding in November 2020 and November 2021. In 2022 he won a scholarship funded by the French government to carry out his research in France and became Visiting Researcher at the Institut Femto-St.
Abstract:
Neuromorphic models [1,2] are proving capable of performing complex machine learning tasks, overcoming the structural limitations imposed by software systems [3] and electronic neuromorphic models [4]. Recently a photon solitonic neuron model [5] has been developed that is able to receive information, process it and store it. The work we present creates a soliton neural network (SNN) through the interfacing of these neurons [6]. The networks consist of a succession of X-shaped junctions which, recognizing the information propagated within the guides, switch by identifying specific preferential trajectories which constitute bit-by-bit memories. The network can memorize and subsequently use the acquired information to recognize further unknown information. The peculiar characteristic of the SNN is its ability to learn in a plastic way, similarly to what happens in the biological tissue. In the nervous system, neurons exchange signals and recognize incoming patterns thanks to the creation, consolidation and destruction of synaptic bridges. Similarly, our neurons can save the information they receive by self-modifying their structures through variations in the refractive index. We propose a neuromorphic model based on a solitonic-waveguide X-junctions interfacing, as shown in fig. 1, obtained by interfacing two input soliton neurons (fig 1a), whose channels give rise to three layers: an input layer, a hidden layer and an output layer as reported in fig 1b. Fig 2. re-proposes network training on four different configurations. Each configuration is characterized by only one channel active while the others are off. Training consists in injecting for several cycles the signal that modifies the refractive index map. Then, inserting signals into all the input channels show a high output response only in correspondence with the trained channel.
Albrecht Lindinger
Institute for Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195 Berlin, Germany
Title: Polarization shaped laser pulses for selective two-photon excitation of autofluorescent molecules
Biography:
Albrecht Lindinger has earned his PhD on helium droplet spectroscopy in Gottingen in the group of Prof. Dr. J.-P. Toennies and took his postdoc term in Berkeley in the group of Prof. Dr. D. Neumark. He received his habilitation in the field of coherent control at the Freie Universität Berlin in the group of Prof. Dr. L. Wöste and is now a lecturer (PD) in the Institute of Experimental Physics at the Freie Universität Berlin. He has published 91 peer-reviewed papers in reputed journals. His main scientific interests are laser optics, coherent control, and bio photonics.
Abstract:
In recent years multiphoton excitation of biological samples by using ultrashort laser pulses became an important imaging method. Fluorescent molecules were employed to distinguish between tissue structures, and a high contrast is required for microscopic imaging. Thereto, laser pulse shaping provides a powerful tool by tailoring the pulses such that two species may selectively be excited. In particular, shaping of laser pulses is applied to exploit intrapulse interference effects in multiphoton excitation. Physically relevant parameters like chirps and polarization states can be controlled which yields perspectives of utilizing all light properties.
In this contribution pulse shaping methods for improved multiphoton excited fluorescence contrast are applied on auto fluorescing biomolecules after transmitting a nanostructured kagome fibre. Antisymmetric phase functions are employed for contrast enhancement of auto fluorescing vitamins. Moreover, phase and polarization tailored pulses are generated to optimally excite one dye in one polarization direction and simultaneously the other dye in the other polarization direction. Polarization sensitive contrast is obtained for the coenzymes nicotinamide adenine dinucleotide (NADH) and Flavin adenine dinucleotide (FAD), which give a measure for metabolic activity. This could provide non-invasive diagnostic information about tumour genesis without exogenous markers.
Moreover, combined temporal and spatial pulse shaping for lateral and axial two-photon excited fluorescence is reported by utilizing a temporal pulse shaper and a subsequent spatial pulse shaper. In particular, a depth dependent excitation of different dyes is performed which leads to a high axially resolved fluorescence contrast. The introduced spatial and temporal shaping technique provides new perspectives for bio photonic imaging applications.