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We report the first experimental characterizations of the coupling efficiencies of a series of e-beam fabricated focusing non-uniform grating couplers interfaced with a horizontal fiber coupling-scheme and designed for multiple Silicon-On-Insulator thicknesses, spanning between the 220 and 340 nm standard platforms. The design of nonuniform grating couplers is tackled either from an engineering perspective focused on to the optimization of the structures for this particular coupling-scheme; and a physics perspective related to the investigation of the scattering process of each structure for a complete comprehension of its performance in support to the experimental findings. Measured coupling efficiencies, up to 83% for the 340 nm platform at 1550 nm, are reported showing to be in excellent agreement with the theoretical findings. The physics behind the scattering process of each structure is investigated taking advantage of the Finite Difference Time Domain method to obtain a deeper understating of the coupling efficiencies. Consequently, a new parameter, the integrated leakage factor, together with the variation of the effective refractive index, across the local pitches, are calculated. Our belief is that any coupling structure for grating coupling can benefit from the proposed designed approach, as a widely applicable technique.

In this work we experimentally demonstrate a fully packaged one-dimensional beam steering system that is based on a fully CMOS compatible silicon photonics platform. This configuration enables multi-wavelength operation and is suitable for short-wavelength infrared (SWIR) applications from light detection and ranging (LIDAR) to telecommunication and sensing applications. The switching fabric in this system employs a 1x9 array of add/drop ring resonators that are fed by a common waveguide through a single etch input grating. The switching fabric re-directs the resonance wavelengths at each drop waveguide to the output facet at the edge of the chip and into free space. The divergent beams that exit the waveguides along the output facet are then collimated and magnified using an array of micro-lenses (pitch = 750 μm, Diameter = 700 μm) in addition to a two lens afocal system in order to enhance the fill factor and diminish any blind zones between adjacent beams. Each one of these drop waveguides is used to address portion of the steering aperture. Combined together they enable steering across the entire aperture. Multi-wavelength operation is obtained by placing individual titanium tungsten alloy (TiW) heaters on top of each ring resonator to enable wavelength tuning.

Plasmonic gratings are attracting huge interest in the context of realizing sensors based on surface-enhanced fluorescence. The grating features control the plasmonic modes and consequently have a strong effect on the fluorescence response. Within this framework, we focused on the use of a buffer solution flowing across the grating active surface to mimic a real measurement. The refractive index of the surrounding medium is therefore altered, with a consequent modification of the resonance conditions. The result is a shift in the spectral features of the fluorescence emission accompanied by a reshaping of the fluorescence emission in terms of spectral weight and direction.

Synthetic Aperture Radar (SAR) is a well-known technique for remote sensing applications with great advantages like uninterrupted imaging capabilities even at night or in presence of cloud cover. However, spaceborne SAR sensors face major challenges like cost and size, which are among the great barriers against their applicability for future constellations of low-Earth observation applications. SAR sensors are not compact and require large or medium-sized satellites weighting hundred kilograms or more, which cost hundreds million dollars. To solve these challenges, the recently started SPACEBEAM project, funded by the European Commission, aims at developing a novel SAR receiver approach, i.e., the Scan-on-Receive (SCORE), exploiting a hybrid integrated optical beamforming network (iOBFN) that also realizes the electro-photonic down-conversion of RF signals. The compactness and frequency flexibility of the proposed photonic solution complies with the requirements of future constellations of low-Earth orbit satellites in terms of size, weight, power consumption, and cost. A high-level representation of the SCORE SAR receiver module based on the multi-functional hybrid photonic integrated circuit (PIC), with 12 input RF channels and 3 output beam-formed IF channels, is shown in the submitted PDF document. For this design, we target the development of an X-band SCORE-SAR receiver having a swath width of 50 km (5 times wider than state-of-art spaceborne SAR systems), and enabling 1.5 m spatial resolution in both along-track and across-track directions. During the conference, we will present the design and specifications of the SCORE-SAR receiver at equipment level, where we aim at a hermetically packaged PIC that is also designed for space compliance. We target a flight-design for the RF front-end and control electronics, enabling the electro-photonic frequency down-conversion of the RF signals and the fast control of the PZT-driven iOBFN with

Recent advances in the nanofabrication and modeling of metasurfaces have shown the potential of these systems in providing unprecedented control over light–matter interactions at the nanoscale, enabling immediate and tangible improvement of features and specifications of photonic devices that are becoming always more crucial in enhancing everyday life quality. In this work, we theoretically demonstrate that metasurfaces made of periodic and non-periodic deterministic assemblies of vertically aligned semiconductor nanowires can be engineered to display a tailored effective optical response and provide a suitable route to realize advanced systems with controlled photonic properties particularly interesting for sensing applications. The metasurfaces investigated in this paper correspond to nanowire arrays that can be experimentally realized exploiting nanolithography and bottom-up nanowire growth methods: the combination of these techniques allow to finely control the position and the physical properties of each individual nanowire in complex arrays. By resorting to numerical simulations, we address the near- and far-field behavior of a nanowire ensemble and we show that the controlled design and arrangement of the nanowires on the substrate may introduce unprecedented oscillations of light reflectance, yielding a metasurface which displays an electromagnetic behavior with great potential for sensing. Finite-difference time-domain numerical simulations are carried out to tailor the nanostructure parameters and systematically engineer the optical response in the VIS-NIR spectral range. By exploiting our computational-methods we set-up a complete procedure to design and test metasurfaces able to behave as functional sensors. These results are especially encouraging in the perspective of developing arrays of epitaxially grown semiconductor nanowires, where the suggested design can be easily implemented during the nanostructure growth, opening the way to fully engineered nanowire-based optical metamaterials.

The outbreak of COVID-19 and national measures undertaken to tackle the spread of the virus may cause significant disruption to the provision of education opportunities for learners and teachers. In Italy, most schools did not practice online teaching before the emergency, and in a short time head teachers, teachers, students had to face new technological tools and deal with a new type of teaching. The PPS – “Problem Posing and Solving” – project offered to all Italian teachers and schools, for free, a way of carrying out Online Education through a nationwide integrated Digital Learning Environment (DLE). In this paper we present a case study of a high school that used one DLE for online teaching of the entire school, embedded in a larger DLE at national level. The goal of this research is to present the integrated DLE of the project and the reasons why this case study can represent an effective model for online teaching of a school under different dimensions (technological, human and pedagogical). The results show that the teachers and the school head agree with our point of view. Most teachers are very supportive of using one DLE and think that this facilitates students and collaboration among teachers. Being included in a larger project allows teachers to compare, collaborate and share experiences and materials with teachers from all over Italy, and to have continuous technical and training support.

Many educational institutions have been closed to contain the spread of COVID-19 and teachers took action to continue education through remote learning with the use of technologies. The context of this research is a community of Italian STEM teachers from different secondary schools, within the Ministerial Project PPS for what purpose it was used; and whether this type of resource is related to the participation of the students in the course. Analysis shows that there are teachers who have conducted the entire course with this teaching material. They have used Maple in a meaningful way to propose problem-solving activities, theoretical explanations, interactive resources, explanation of Maple commands and text of exercises and resolution. Representative examples of each category are shown. Student views of worksheets increase when teachers use at least three categories of worksheets within a course. In particular, student participation increases when using the problem solving methodology. This type of resources is very effective for online teaching, where immediate feedback and interactivity are essential to involve students more.

The field of silicon photonics has experienced widespread adoption in the datacoms industry over the past decade, with a plethora of other applications emerging more recently such as light detection and ranging (LIDAR), sensing, quantum photonics, programmable photonics and artificial intelligence. As a result of this, many commercial complementary metal oxide semiconductor (CMOS) foundries have developed open access silicon photonics process lines, enabling the mass production of silicon photonics systems. On the other side of the spectrum, several research labs, typically within universities, have opened up their facilities for small scale prototyping, commonly exploiting e-beam lithography for wafer patterning. Within this ecosystem, there remains a challenge for early stage researchers to progress their novel and innovate designs from the research lab to the commercial foundries because of the lack of compatibility of the processing technologies (e-beam lithography is not an industry tool). The CORNERSTONE rapid-prototyping capability bridges this gap between research and industry by providing a rapid prototyping fabrication line based on deep-UV lithography to enable seamless scaling up of production volumes, whilst also retaining the ability for device level innovation, crucial for researchers, by offering flexibility in its process flows. This review article presents a summary of the current CORNERSTONE capabilities and an outlook for the future.

Fluorescence spectroscopy has been extensively investigated for disease diagnosis. In this framework, optical tissue phantoms are widely used for validating the biomedical device system in a laboratory environment outside of clinical procedures. Moreover, it is fundamental to consider that there are several scattering components and chromophores inside biological tissues and the interplay between scattering and absorption may result in a distortion of the emitted fluorescent signal. In this work, the photophysical behaviour of a set of liquid, tissue-like phantoms containing different compositions was analysed: phosphate buffer saline (PBS) was used as the background medium, low fat milk as a scatterer, Indian ink as an absorber and protoporphyrin IX (PpIX) dissolved in dimethyl formamide (DMF) as a fluorophore. We examined the collected data in terms of the impact of surfactant Tween-20 on the background medium, scattering effects and combination of scattering and absorption within a luminescent body on PpIX. The results indicated that the intrinsic emission peaks are red shifted by the scattering particles or surfactant, whilst the scattering agent and the absorbent can alter the emission intensity substantially. We corroborated that phantoms containing higher surfactant content (>0.5% Tween 20) are essential to prepare stable aqueous phantoms.

Semiconductor nanowire ordered arrays represent a class of bi-dimensional photonic crystals that can be engineered to obtain functional metamaterials. Here is proposed a novel approach, based on a particle swarm optimization algorithm, for using such a photonic crystal concept to design a semiconductor nanowire-based two-dimensional diffraction grating able to guarantee an in-plane coupling for light trapping. The method takes into account the experimental constraints associated to the bottom-up growth of nanowire arrays, by processing as input dataset all relevant geometrical and morphological features of the array, and returns as output the optimised set of parameters according to the desired electromagnetic functionality of the metamaterial. A case of study based on an array of tapered GaAs-AlGaAs core–shell nanowire heterostructures is discussed.

This paper presents a preliminary evaluation of the technical and economic feasibility of a low-enthalpy geothermal system for air conditioning and its integration with other systems, including a photovoltaic plant and an electrical storage system. The pilot building is a research center located in the southern side of the Mediterranean basin (Sardinia, Italy). Preliminarily, the main geological, hydrogeological and geothermal characteristics of the area were analyzed. Then, an energetic assessment of the building and its plants was performed. The hourly production of a photovoltaic plant already designed for the building was assessed. To improve the energy efficiency and the thermal energy self-consumption, an alternative thermal generation plant was proposed to replace the existing air conditioning system: a water-water heat pump coupled with a low-enthalpy geothermal probe (vertical configuration), to be embedded into the ground or placed into an existing groundwater well. The feasibility of electric storage was evaluated by considering a system capacity of 100 kWh to temporarily store and self-consume the electricity overproduced by the photovoltaic plant. A preliminary economic assessment showed the viability of the photovoltaic system. The 100 kWh-capacity electric storage will increase the self-production percentage, but it is not economically affordable. The replacement of the current air-water heat pumps with one water-water heat pump will be economically convenient if coupled with a groundwater geothermal probe, but the solution of a vertical probe embedded into the ground is unsustainable, due to high drilling costs.

Problem solving and computational thinking are the key competences that all individuals need for professional fulfillment, personal development, active citizenship, social inclusion and employment. In mathematics, during contextualized problem solving using Maple, the differences between these two skills become thinner. A very important feature of Maple for problem solving is the programming of animated graphs: an animation obtained by generalizing a static graph, choosing the parameter to be varied and its interval of variation. The first objective of this research is to analyze the computational thinking processes behind the creation of animated graphs for the resolution of a contextualized problem. To this end, we selected and analyzed some resolutions of problems carried out by fourth-grade students of upper secondary schools in Italy (grade 12). The paper shows some examples in which different processes of computational thinking have emerged, which reflect resolutive strategies and different generalization processes. From the analysis it emerged that all the processes underlying the mental strategies of the computational thought useful for solving problems are activated in the creation of animated graphs. In the second part of the article we discuss examples of animations created during training activities with secondary school teachers, and how animations can support the learning of scientific concepts. It is very important to train the teachers in this regard, both to understand the processes that the students would activate during the creation of animated graphics and to enrich the theoretical or practical explanations with animated representations.

Metasurfaces made of arrays of vertically aligned semiconductor nanowires are suitable platforms for light management in optical and photonic applications. Here we report a design approach aimed at engineering the optical behavior of semiconductor nanowire ensembles randomly displaced on the substrate, in order to enhance modulation effects in their optical reflectance response. By resorting to analytical and numerical simulations we demonstrate that the combined implementation of a multi-shell layering together with a tapered designing on the individual nanowire offer new opportunities to tailor the optical reflectance oscillations in this kind of architectures. The simulation insights were compared to experimental results reported for self-assembled GaAs nanowires and GaAs/AlGaAs core-shell nanowires. The proposed approach is especially promising for epitaxially grown semiconductor nanowires, where the suggested design modifications can be easily implemented during the nanostructure growth.

Fluorescence spectroscopy has been extensively investigated for disease diagnosis. In this framework, optical tissue phantoms are widely used for validating the biomedical device system in laboratory environment outside clinical procedures. Moreover, it is fundamental to consider that there are several scattering components and chromophores inside biological tissues and the interplay between scattering effects and absorption can result in a distortion of the emitted fluorescence signal. In this work, the photophysical behaviour of a set of liquid tissue like phantoms containing different compositions was analysed: phosphate buffer saline (PBS) was used as background medium, low fat milk as a scatterer, India ink as an absorber and PpIX dissolved in dimethyl formamide (DMF) as fluorophore. We examined the collected data in terms of the impact of surfactant Tween-20 on the background medium, scattering effects and combination of scattering and absorption within a luminescent body on PpIX. The results indicated that the intrinsic emission peaks are red-shifted by the scattering particles or surfactant, whilst the scatterer and absorber can alter the emission intensity substantially. We corroborated that phantoms containing higher surfactant content (< 0.5% Tween 20) are essential to prepare a stable aqueous phantoms.

A specific and robust design-routine for the optimization of Grating-Couplers (GCs) has been created resorting to the well-known Particle Swarm Optimization (PSO) algorithm implemented inside a commercial software based on the Finite Difference Time Domain (FDTD) method. The combination of the PSO algorithm and the FDTD method can represent a powerful tool for optimizing several GC structures through a well-defined model that governs the GC performances as a function of their structural parameters. The final output of our design-routine is a file, which can be directly imported inside lithographic control interfaces for the writing steps. To validate our design-routine, a comparison between our results and two ‘gold’ structures, reported in literature, is proposed. As an application, the optimization of a GC for planar Fiber-to-GC coupling, which is interesting from a photonics packaging prospective, is provided. The aim is to show the recovering of the 0.6 dB higher insertion-losses related to this scheme respect to the bulkier vertical Fiber-to-GC geometry used as the standard-configuration for grating-coupling.

In an Italian and European context, one of the fundamental skills in Mathematics is the ability to solve problems in everyday situations, often linked to everyday life. For this reason, the problem posing and solving methodology plays a fundamental role in the process of teaching and learning Mathematics. This paper presents the results of the immersive experience "Mathematical Exploration with Problem Posing and Solving", included in the teacher training activities proposed by the national PP&S - Problem Posing & Solving - Project of the Italian Ministry of Education, which aims at enhancing the teaching and learning of Mathematics by using new methodologies and technologies. In particular, the focus will be on the work and considerations of the 50 teachers who took part in the project, from both primary and secondary school. They were guided through the individual step-by-step creation of a contextualized problem, following a process guided through stimulus-based questions. This immersive experience brought about the production of valid problems and was full of very stimulating teachers' considerations on the various phases of the problem posing and solving.

Random assemblies of vertically aligned core&ndash, shell GaAs&ndash, AlGaAs nanowires displayed an optical response dominated by strong oscillations of the reflected light as a function of the incident angle. In particular, angle-resolved specular reflectance measurements showed the occurrence of periodic modulations in the polarization-resolved spectra of reflected light for a surprisingly wide range of incident angles. Numerical simulations allowed for identifying the geometrical features of the core&ndash, shell nanowires leading to the observed oscillatory effects in terms of core and shell thickness as well as the tapering of the nanostructure. The present results indicate that randomly displaced ensembles of nanoscale heterostructures made of III&ndash, V semiconductors can operate as optical metamirrors, with potential for sensing applications.

Problem solving, i.e. the ability to model concrete situations in mathematical terms and to solve the problems connected to them, plays an important role in teaching and learning Mathematics to and by students at every level of education and is one of the basic skills for the training of citizens. By learning problem solving in Mathematics, students acquire ways of thinking, creativity, curiosity, collaborative skills and confidence in unfamiliar situations, from which they will benefit also outside the Mathematics classroom. The use of digital technologies helps in both representing and exploring mathematical tasks. Technologies also provide a range of tools and opportunities to structure and support learning environments in which students continually interact to build knowledge and solve problems. The national PP&S - Problem Posing & Solving - Project of the Italian Ministry of Education aims to enhance the teaching and learning of Mathematics and Informatics using new methodologies and technologies. One of the methodologies is problem solving through the use of an Advanced Computer Environment (ACE). An ACE is a system that allows one to perform numerical and symbolic calculation, make graphical representations in 2 and 3 dimensions and create mathematical simulations through interactive components. Moreover, it is able to support students in reasoning processes, in the formulation of exit strategies and in the generalization and re-adaptation of the solution in different contexts. The goal of this paper is to discuss the results of an immersive workshop, entitled "Mathematical Exploration with Problem Posing and Solving", involving 50 secondary school Maths teachers, who were invited to reflect on the role of an ACE in learning and teaching Mathematics through problem posing and solving. During the workshop were presented the problem solving methodology used in the PP&S project and an example of a contextualized problem solved with the use of an ACE. The results emerged from the analysis of the questionnaires (initial and final) compiled during the workshop and a study of the works delivered by the teachers, who were asked to design a problem, its resolution and generalization through the use of an ACE. They are useful to understand teachers' reflections on the methodologies proposed and on the impact of new technologies on teaching.

Enhancing language skills is a duty for many institutions, schools and universities; Information and Communications Technology is nowadays supporting language teaching, heading also to the integration of foreigners. According to previous studies, the use of a Technology Enhanced Learning Environment can foster language competences through online tests. The goal of this paper is to show and discuss different typologies of automatically evaluated questions useful to learn languages and designed with an Automatic Assessment System, already successfully used for teaching STEM disciplines: Science, Technology, Engineering and Mathematics. This work has been carried out thanks to the collaboration between the Department of Mathematics and the Department of Foreign Languages. Five different typologies of questions are analysed: "Combining sentence elements" asks to combine given elements to form at least three correct and meaningful sentences; "Find the mistake" asks whether a sentence is grammatically correct and to explain why; "The Target puzzle" asks to join words together using precise links; "Scrambled text" asks the student the correct sequence of sentences in a scrambled text; "The Encrypted Crossword puzzle" is a crossword puzzle without definition clues. Linguists consider these question types effective to develop language competences and have already used them profitably in traditional teaching and language learning. To engage the learner and increase motivation, we will develop an implementation where the questions are self-evaluated, always available, with immediate and interactive feedback. These tools could be used in online language courses and in all those teaching activities that are carried out remotely by the student alone. All questions are outlined with the explanation of the grading code and a triplet of descriptors; they describe the Performance, Requirements and Objectives of each question and allow further studies on automatic detection of the relatedness between different language learning objects, in order to construct adaptive language tests.

The phenomenon of globalization that concerns the modern era, pushed by technological evolution, has led to several changes in the field of education. Not only are education policies of the single States adapting by directing towards European models: the possibility for a student to choose a university is increasing all over the world, too. In order to facilitate students who want to enroll at a European university and who come from countries with less than 12 years of compulsory schooling, our University designed the Foundation Programme. This is an additional year that allows to earn 60 ECTS to reach the 12 years of schooling, a basic requirement for university access in Europe. The main feature of this project is that it is delivered online; this allows to reduce the costs of enrollment and allows students to attend it directly from home in their country. The design, structure and methodologies of the project are described and discussed in this article.

We compare the simulated optical insertion-losses and fabrication-tolerances of a micro-optical bench (MOB) for laser hybrid-integration on the 220nm Silicon-on-Insulator (SOI) photonic-platform to standard fiber-to-grating coupling. Our millimeter-scale two-dimensional finite difference time domain (2D-FDTD) simulation captures (i) aberration, (ii) reflection, (iii) diffraction, and (iv) wave-guiding effects in a single-shot and completely self-consistent way, indicating that light from a laser-diode can be coupled to the SOI photonic integrated circuit (PIC) with a 2.8dB insertion-loss at 1550nm. This insertion loss is just 1.0dB higher than for a standard Fiber-to-PIC grating-coupler, and is due to a combination of interface-reflections and aberration-effects from the micro-optical elements in the MOB. We use further 2D-FDTD simulations to investigate the alignment and manufacturing tolerances of the MOB, and show that these are compatible with practical photonic-packaging processes for mass-manufacture.

This paper presents a model for school remedial, focusing on improving the digital materials sharing process for the diversification of tutoring strategies. The model involves the characterization of materials for automatic assessment shared within a community of tutors. The characterization expects materials to be linked with natural language descriptors explicating their intended instructional objectives. The possibility of implementing a recommendation system on the basis of natural language processing techniques is discussed taking in consideration an analysis of the application of the model within a local-scale project. Clustering techniques searching for materials that have the same educational purposes but involve the activation of different cognitive processes are proposed, in order to continuously extend the database of shared materials in favour of the effectiveness of ongoing tutoring actions. The results collected from questionnaires submitted to students, tutors, and teachers involved in the project are shown, and clustering data are discussed highlighting the feasibility of the application of the model.

Supporting students in the transition from secondary school to university is an important action to be taken in order to increase the number of people with tertiary education degrees; it has positive consequences on the citizens’ working perspective and on the national economic growth. To this purpose, in the academic year 2014/2015 the University of Turin started the Project Orient@mente, a platform of self-paced open online courses aimed to guide students in the choice of a scientific university program. This paper focuses on the design of the Realignment Course in Mathematics, provided by the platform and aimed at the self-paced review and integration of knowledge that students are required to acquire during secondary school. Materials are created and structured according to the User Experience Design for Learning, with the aim of providing a valuable learning experience to students. Contents are delivered through an accessible learning management system integrated with an advanced computing environment and an automatic assessment system. Data from the usage of the activities and from the results of the online tests are analyzed in order to validate the design choices and the coherent structure of the course.

Computer codes are widely used to predict heat transfer fields. Modeling is accomplished in multidimensional media with homogenous or not homogenous thermal conductivity, with or without volume heat sources and enthalpy flux. This paper compares the analytical solution of temperature fields in a few physical cases such as aliment cakes, capacitors, gas turbine blades, tanks with infinite element computer results and experimental results. The analytical solution of heat transfer partial differential equations presented in this paper appears in the form of the sum of effects. One of them is an infinite series in term of eigenvalues that is easily managed through mathematical commercial codes available even for palmar calculations. A comparison with experimental results shows that the concept of analytical solution has application in many physical phenomena without going to the complexity of computer code modeling.

Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize the experimental findings in the long wavelength regime, whereas numerical simulations fully reproduce the experimental outcomes in the entire frequency range. The impact of the refractive index of the medium surrounding the nanostructure assembly on the reflectance was estimated. In view of the present results, sensing schemes compatible with microfluidic technologies and routes to innovative nanowire-based optical elements are discussed.

We report on the optical and photo-physical properties of a fluorinated poly(p-phenylenevinylene) derivative, namely poly(2-methoxy-5-[(2-ethylhexyl)oxy]-1,4-phenylenedifluorovinylene) (MEH-PPDFV) and we compare them with those of the well-known non fluorinated reference system, poly(2-methoxy-5-[(2-ethylhexyl)oxy]-1,4-phenylenevinylene) (MEH-PPV) synthesized with the same procedure. Remarkable blue-shifts of absorption and emission spectra of MEH-PPDFV with respect to MEH-PPV are observed, due to the larger distortion from planarity of the fluorinated species. In addition, the blue-shift for optical transitions in absorption spectra is more pronounced than in emission ones, since the molecule conformation in the excited states is more planar than in the ground one. Microsecond photo-induced absorption spectra of MEH-PPDFV reveal three bands possessing spectral properties and/or kinetics different from those observed for MEH-PPV. The assignment of these transitions is provided in terms of free and trapped polarons as well of triplet excitons. Free-polarons have an intrinsic decay constant of 3 μs, while the trapping dynamics has a longer kinetics of 40 μs. The triplet exciton, instead, shows a monoexponetial decay behavior of constant about 10 μs.

Grating couplers are widely used optical interfaces in integrated photonics, especially on the Silicon-On-Insulator (SOI) platform. Their design has been optimized for coupling light between a Photonic Integrated Circuit (PIC) and a single-mode fiber, a µlens for free space transport, or even a second PIC in the same SOI platform. In this work, we co-design matching pairs of grating-couplers on distinct SOI and InP photonic platforms for optimized PIC-to-PIC coupling. By matching the scattering strengths of the two grating-couplers, we show that a PIC-to-PIC insertion loss of 3dB can be achieved. We also investigate how the design parameters impact the coupling efficiency and the bandwidth, ending up with a tolerance analysis. The proposed coupling approach between two different waveguide materials has prospective applications for the hybrid-integration of SOI and InP photonic platforms for communication technologies.