DAY 1: Monday, 1st July 2019
|09:00 – 09:30||Introduction by Professor Marco Romagnoli, CNIT (Italy)|
Professor Romagnoli will open the school with an introduction about the school, the host institute, and ePIXfab.
|09:30 – 10:30||Passive Silicon Photonics by Professor Andrea Melloni, Politecnico di Milano (Italy)|
The analysis and design of advanced and complex photonic integrated circuits is an art that have to consider subtle aspects, technological details, tricks and skills that expert in the field accumulate in years of activity. The lecture assumes a certain level of confidentiality with integrated optic theory and provides a panorama of the potentials and limits of the silicon photonic platform to implement passive functionalities. Aspects apparently trivial or negligible that can have a large impact on the overall performance of the entire circuit will be considered with detail.
The topics include aspects related to the index contrast and effective and group index with a comparison between technologies, backscatter, crosstalk and attenuation. Rings resonators will be treated in detail, starting from an historical survey and going through theory and applications. The state of the art of passive devices will be shown and the hoary problem of the coupling with silicon waveguide discussed. The effect of tolerances will be introduced and simple consideration on robust design, statistical analysis and yield estimation mentioned.
Several arguments have the scope to trigger further interests and are propaedeutic to the other lectures.
|11:00 – 12:00||Silicon Photonics Modulators by Dr. Laurent Vivien C2N, CNRS, Univ. Paris-Sud, Univ. Paris Saclay (France)|
Silicon photonics has been the subject of intense research activities as a compelling technology paving the way for next generation of energy-efficient high-speed computing, information processing and communications systems. The vision is to provide a mature integration platform supported by the CMOS manufacturing infrastructure to cost-effectively produce integrated optoelectronic circuits for a wide range of applications, including telecommunications, optical interconnects, spectroscopy, Quantum photonics, biological and chemical sensing…
This lecture will be focus on optical modulation in silicon photonics platform. Basic optical properties, state of the art, device integration, … will be introduced during the lecture as follows:
- Light modulation in silicon platform
- Physical effects and figures of merit
- Experimental results
- Trends in modulation
|12:00 – 13:00||Silicon Photonics Detectors by Dr. Laurent Vivien C2N, CNRS, Univ. Paris-Sud, Univ. Paris Saclay (France)|
This lecture will be focus on the development of waveguide photodetectors in silicon photonics platform. Basic optical properties, state of the art, device integration, … will be introduced during the lecture as follows:
- Light detection
- Material choice
- Experimental results
- Conclusion and trends
|14:00 – 15:00||Lasers in Silicon Photonics (Wafer Bonding) by Dr. Bertrand Szelag, CEA LETI(France)|
In this lecture, I will introduce the main achievements in the field of integrated hybrid laser on silicon through molecular bonding. The basics of the different bonding techniques will be presented with a focus on their advantages and drawbacks. Hybrid laser integration on silicon photonic platform will be extensively discussed with a focus on large scale integration capable fabrication.
|15:00 – 16:00||Lasers in Silicon Photonics (Transfer Printing) by Professor Gunther Roelkens, Ghent University-imec (Belgium)|
In this lecture I will introduce the micro-transfer-printing technique as an enabling heterogeneous integration technology for silicon photonics. After discussing the basics of the technique and the advantages/disadvantages compared to other integration approaches such as flip-chip integration and wafer bonding, I will discuss several demonstrations of the technique, focused on III-V-on-silicon photonic devices.
|16:30 – 17:30||Lasers in Silicon Photonics (Direct Epitaxy) by Dr. Chen Siming, University College London (UK)|
The available of silicon-based laser is the key technology for the whole silicon photonics industry. But the indirect bandgap of silicon is a severe limitation, and, despite recent advances, Group IV-based light emitters will not, in the foreseeable future, outperform their III-V counterparts. Much effort has been directed toward hybrid integration of III-V lasers with silicon photonics platforms. Although impressive results have been achieved, on a longer term, the direct epitaxial growth of III–V semiconductor lasers on silicon remains the ‘holy grail’ for full-scale deployment of silicon photonics with reduced cost and added ﬂexibility. Semiconductor lasers with active regions made from quantum dots (QDs) have shown superior device performance over conventional quantum well (QW) counterparts and offer new functionalities. Furthermore, there are other advantages of QDs for monolithic III–V-on-Si integration over QWs, such as QD devices being less sensitive to defects. It is, therefore, not surprising that the past decade has seen rapid progress in research on direct growth of III–V QD lasers on Si, with a view to leveraging the beneﬁts of QD gain region technology while beneﬁtting from the economics of scale enabled by direct growth.
In this lecture, we summarise recent achievements for III–V QD lasers epitaxially grown on Si substrates and describes how QD technology has opened up new avenues in monolithic III–V-on-Si integration technology, enabling efﬁcient and reliable Si-based lasers for Si photonics.
|17:30 – 18:00||ePIXfab and European Open-Access Silicon Photonics by Dr. Abdul Rahim (ePIXfab-Ghent University)|
This short presentation will introduce the activities and mission of ePIXfab – the European Silicon Photonics Alliance to the participants of the school. Moreover, a summary of various open-access silicon photonics platforms, their access mechanism and the latest developments made by these platforms will also be a part of the presentation.
10:30-11:00: Coffee Break
13:00-14:00: Lunch Break
16:00-16:30: Coffee Break
DAY 2: Tuesday, 2nd July 2019
|09:30 – 10:30||Nonlinear optics: moving from fiber to integrated approaches by Professor Camille Sophie Brès, EPFL (Switzerland)|
Nonlinear wavelength conversion in waveguides enables large bandwidth all-optical signal processing at the femtosecond time scale, optical amplification and lasing, and also distant light generation and emission of non-classical state of light. Following fiber-optic platforms, integrated photonics has recently enabled many such studies, owing to the high optical confinement and the large nonlinear index of many integrable materials. It appears today as a possible solution to decrease required pump powers for the design of more practical devices. The potential integration of optical and electrical functionalities on the chip level leveraging CMOS fabrication technology has also been an undeniable driving force.
In this talk, we will cover some fundamentals of nonlinear optics in fibers and integrated waveguides (the Kerr effect and nonlinear scattering effects) and consider important parameters that favor or hinder such interactions. We will also look at studies and demonstrations performed in both fiber and CMOS platforms to see how performances compare and have evolved, and where nonlinear integrated optics can take us.
|11:00 – 12:00||Photonic wire bonding and Hybrid Integration on the Silicon Platform: From High-Speed Communications to THz Signal Processing by Professor Christian Koos, KIT (Germany)|
Silicon represents an excellent material system for photonic integration when considered from a technological point of view, enabling large-scale fabrication by highly optimized CMOS processes along with monolithic co-integration of photonic and electronic circuits. From a functional point of view, however, the silicon photonic platform falls short of distinct material properties that would are key to certain applications. Hybrid photonic integration can overcome these deficiencies by combining silicon photonic circuits with complementary material systems.
This lecture will give an overview on different hybrid integration concepts, comprising package-level multi-chip assemblies that rely on 3D-printed optical structures, hybrid on-chip integration of organic materials using back-end-of-line (BEOL) processes, as well as combinations of silicon waveguides and plasmonic nanostructures that open new perspectives for THz signal processing.
|12:00 – 13:00||Integrated Brillouin photonics by Professor Ben Eggleton, University of Sydney (Australia)|
A recent renaissance in Brillouin scattering research has been driven by the increasing maturity of photonic integration platforms and nanophotonics. The result is a new breed of chip-based devices that exploit acousto-optic interactions such as lasers, amplifiers, filters, delay lines and isolators. I will overview Brillouin scattering in integrated waveguides and resonators, covering key concepts such as the stimulation of the Brillouin process, in which the optical field itself induces acoustic vibrations, the importance of acoustic confinement, methods for calculating and measuring Brillouin gain, and a diversity of materials platforms and geometries. I will review emerging applications in microwave photonics, signal processing and sensing, and conclude with a perspective for future directions.
|15:00 – 16:00||Plasmonics Communications by Professor Juerg Leuthold, ETH (Switzerland)|
Plasmonics is increasingly attracting the attention of the communications community as it promises ultra-compact size, fast speed and lowest power consumption. And indeed, devices with 500 GHz bandwidth on the micrometerscale with fJ/bit operation have already been demonstrated. Yet, plasmonics also offers challenges such as high losses and critical fabrication tolerances.
In this lecture we will start with an introduction into the plasmonic fundamentals. In a second step we will give an overview on plasmonic concepts and devices. The lecture will end with a visionary outlook on what plasmonics might enable in the future.
|15:00 – 16:00||Transceivers System architecture and modulation formats by Professor Jeremy Witzens, RWTH Aachen (Germany)|
In this first lecture I will cover general aspects of electro-optic transceiver system architectures and of modulation formats. After covering general aspects related to signal integrity, compensation techniques such as pre-emphasis and equalization, and aspects related to forward error-correction and latency in the context of simple on-off keying, I will cover more complex modulation schemes including pulse amplitude modulation, direct detection discrete multitone, and coherent encoding formats. This will be followed by a discussion of analog and digital receiver architectures and their applicability to different application spaces.
|16:30 – 17:30||Transceiver in silicon PICs by Professor Jeremy Witzens, RWTH Aachen (Germany)|
In this second lecture on electro-optic transceivers I will cover specifically their implementation in silicon photonics PICs and compare it to the state of the art of other transceiver technologies. After covering aspects related to the chip-scale, the lecture will also cover packaging related aspects such as thermal management in compact form factors.
|17:30 – 18:00||European Photonics Industry Consortium (EPIC) Presentation by Dr. Jose Pozo (EPIC)|
10:30-11:00: Coffee Break
13:00-14:00: Lunch Break
16:00-16:30: Coffee Break
DAY 3: Wednesday, 3rd July 2019
|09:30 – 10:30||Integrated linear & nonlinear photonics for ultra-high capacity communications by Professor Leif Katsuo Oxenløwe, Denmark Technical University (Denmark)|
Photonic integration has obvious benefits on e.g. energy consumption of transceivers, and allows for advanced multiplexing, novel quantum key distribution schemes and high-dimensional quantum information processing. In addition, exploiting the nonlinear response of optical chips, enables broadband WDM sources, terabit per second optical signal processing speeds allowing for ultra-broadband processing of hundreds of data channels simultaneously on a single chip. This presentation will describe recent advances using integrated photonics for ultra-high capacity optical communication systems.
|11:00 – 12:00||Silicon Photonics for Sensor Applications by Professor Roel Baets, Ghent University – imec (Belgium)|
While telecom and datacom applications have been the main driving force behind the development of silicon photonics in the past decade, many examples are emerging at the research level in which the same technology base is used for sensing applications. These applications span a vast and diverse range of sensing modalities. The lecture will start with an overview of these modalities with emphasis on the requirements from the sensing point of view. This includes the choice of an appropriate wavelength range, which is not necessarily compatible with the transparancy window of SOI-waveguides. Therefore a lot of effort is spent on the development of PIC-platforms that can enable both shorter and longer wavelenth ranges. As long as these platforms make use of the same silicon technology base one can see them as variations of a theme in the general field of silicon photonics. Because sensing applications are typically of an analog nature the requirements of a platform (in terms of losses, spurious reflections, temperature sensitivity etc) will typically be different from those in digital applications.
The lecture will finish with a more detailed description of specific sensor cases, such as Laser Doppler Vibrometry and Raman spectroscopy on a chip. Refractive index biosensing, LIDAR and mid-IR spectroscopy are discussed in other lectures.
|12:00 – 13:00||Thick SOI platforms by Dr. Matteo Cherchi, VTT (Finland)|
Even though it may seem a wreck from last century, micron-scale silicon photonics comes with unique properties, including an unusual combination of tight confinement and low propagation losses (≈ 0.1 dB/cm), high power handling, tolerance to fabrication imperfections, low-polarization dependence (including zero-birefringence waveguides), broadband low-loss coupling to optical fibres, and waveguides that are single-mode and low-loss across the whole transparency range of silicon (1.2 ÷ 7 µm). For example, they enable long, compact and low-loss delay lines, mid-infrared sensors, integrated all-silicon Faraday rotators, compact low-loss thermo-optic switches with low power consumption, and ultra-broadband directional couplers. On the other hand, relatively large waveguide cross-sections typically limit the maximum achievable speed of devices like modulators and detectors. I will present the historic development of the micron-scale platform from the very early days of silicon photonics till our recent developments and plans to extend its range of applications.
|14:00 – 15:00||Transceiver Electronic ICs by Professor Johan Bauwelinck, Ghent University – imec (Belgium)|
High-speed electronic integrated circuits are essential to the development of new fiber-optic communication systems. The exponentially increasing data consumption is expanding the application domain of optical communication and driving the development of faster and more efficient transceivers. Fiber-optic communication networks operate on very different scales from very short interconnects in datacenters to very long links between cities, countries or continents. While each application operates on a very different scale with very different requirements (capacity, signal format, cost, power…), they share one thing, their need for application-specific high-speed electronic transceiver circuits such as driver amplifiers, transimpedance amplifiers, equalizers and clock-and-data recovery circuits. As a consequence of the increasing speeds, close integration and co-design of photonic and electronic devices have become a necessity to realize high-performance sub-systems, while such co-design also enables the design of new electro-optic architectures to create and process optical signals more efficiently. This presentation will introduce the basic concepts and illustrate a number of recent and ongoing developments in IDLab, an imec research group.
|15:00 – 16:00||Graphene integrated photonics by Professor Marco Romagnoli, CNIT (Italy)|
In present optical communications systems, integrated photonics is an established technology that combines high performances, miniaturization, low cost and in some case large volume manufacturing. Si Photonics and III-V compound semiconductor are the two platforms used for high performance transceivers. Those two platforms operate in O and C bands with III-Vs providing in a single platform modulator, detector and light source whereas in Si Photonics the light source is external or hybrid but its the integration is not established yet. Nevertheless both SiGe and p-n junction based modulators and Ge p-i-n photodetectors are already validated in products. Graphene is a novel technology that, similarly to III-V’s exhibits both electro-absorption and electro-refraction to be used for light modulation and absorption or additionally photothermal effect for photodetection. Graphene can be integrated on any type of waveguide and therefore is more suitable for the Si platform because of the low initial cost of the wafer. Contrary to modulators in Silicon Photonics graphene does not need implantations because the doping concentration is obtained with a bias voltage. Graphene-based photodetectors can remove the need of Ge epitaxy, replacing the Ge p-i-n photodetectors with a single or double layer of graphene. Graphene photodetectors are not spectrally limited, unlike Ge p-i-n photodetector, that operate below ∼1,600 nm. Graphene-based photodetectors can reach, in principle, speeds of several hundreds of GHz, as a consequence of the high carrier mobility of the material. From fabrication point of view graphene devices are made in post processing not necessarily on expensive SOI wafers which are necessary for Ge epitaxy and for p-n junctions. Graphene Photonics can be realized on SiN or silica waveguides that being wider than Si nanowires will use more relaxed litho nodes. All these factors contribute to simplification of the technology and cost reduction. A more extensive discussion on the perspective of Graphene Photonics can be found in Nat. Rev. Mat. 3, 10 (2018).
|16:30 – 17:30||Mid-IR Silicon Photonics by Dr. Milos Nedeljkovic, University of Southampton (UK)|
The mid-infrared (mid-IR) wavelength range is highly useful for sensing because many gases, chemicals, and biomolecules are identifiable because they strongly absorb light at specific MIR wavelengths. Silicon photonics is attracting interest for the creation of integrated mid-infrared systems for sensing and spectroscopy, but to achieve this new waveguide platforms, light sources, detectors, and passive components will be required.
This lecture will provide an overview of emerging group-IV mid-IR material platforms, and discuss both recent progress in mid-IR silicon photonics devices and some of the remaining challenges.
10:30-11:00: Coffee Break
13:00-14:00: Lunch Break
16:00-16:30: Coffee Break
DAY 4: Thursday, 4th July 2019
|09:30 – 10:30||Advanced Packaging for Silicon Photonics by Professor Giovan Battista Preve, Scuola Superiore Sant’Anna (Italy)|
The only way to make silicon photonics technology completely exploitable at industrial level for volume production is to solve the manufacturing bottlenecks that nowadays limit the applicability of the technology, in particular related to the multiple optical interconnection and the III-V chip integration.
This presentation will give a survey, based principally on the work made at Inphotec labs, on the problems and the challenges related to the packaging of silicon photonic devices and their impact on process automation.
It will give some update to what we are currently doing and developing in our labs utilizing a custom state of the art pigtailing-automated bench, robotics, including their present limitations.
|11:00 – 12:00||Heterogeneous Integration for nonlinear optics by Professor Marc Sorel, University of Glasgow (Scotland)|
We will review recent progress on heterogeneous integration for non-linear optics applications, which will include dispersion engineered waveguides on AlGaAs-on-insulator, vertical integration of AlGaAs microdisks
|12:00 – 13:00||Control Systems for Silicon Photonics Chips by Professor Francesco Morichetti, Politecnico di Milano (Italy)|
The complexity scaling of silicon photonics circuits is raising novel needs related to control. Reconfigurable and programmable architectures need fast, accurate and robust procedures for the tuning and stabilization of their working point, counteracting temperature drifts originated by environmental fluctuations and mutual thermal crosstalk from surrounding integrated devices.
In this lecture, recent achievements on the automated tuning, control and stabilization of integrated photonics architectures are reviewed. Specific focus will be given to the development of on-chip light monitors embedded in key spots of the circuit, low-energy consumption amplitude and phase actuators, advanced techniques for the mitigation of thermal crosstalk, labelling strategies to identify coexisting optical signals inside the photonic circuit, and tuning and locking algorithms.
Several examples of applications are presented that include the automatic reconfiguration and feedback controlled stabilization of switch fabrics based on Mach-Zehnder interferometers (MZIs); wavelength locking platforms enabling feedback-control of silicon microring resonators for the realization of wavelength-division-multiplexing transmitters and reconfigurable hitless filters; on-chip manipulation of spatial modes by using self-configuring meshes of silicon photonics MZIs.
|14:00 – 15:00||Photonics switching using silicon photonics by Dr. Francesco Testa, Ericsson (Italy)|
Silicon photonics switch matrices are considered key devices for the implementation of future optical networking systems thanks to their special characteristics of large bandwidth, very high miniaturization, low loss and low cost. New applications of silicon photonics switch matrices have been proposed to enhance the functionalities of traditional optical transport nodes and to introduce optical switching in 5G wireless systems. Another important application proposed and investigated in many research groups is in intra-data center optical networking. The different switching network architectures will be presented and discussed together with the switch matrix implementations details. Recent advances in the realization of switch matrices prototypes will be reviewed. The design of the switch element types used in silicon photonics will be treated and the performances of the switch matrix will be discussed. Finally, perspectives and future research directions will be suggested.
|15:00 – 16:00||LiDAR using Silicon Photonics by Dr. Jerome Bourderionnet, Thales Research & Technology (France)|
|16:30 – 17:30||Lab Visits|
|17:30 – on wards||Poster Session|
10:30-11:00: Coffee Break
13:00-14:00: Lunch Break
DAY 5: Friday, 5th July 2019
|09:30 – 10:30||Biosensors in Silicon Photonics by Professor Laura Lechuga, ICN2 (Spain)|
Portable point-of care (POC) devices will be a milestone for the achievement of universal Healthcare and Environmental protection. Silicon photonics based-biosensors are the most suitable candidates to achieve this ambitious objective and have made significant progress in the last years. They consist of compact waveguides contained on chips that can be easily miniaturized and fabricated in arrays of identical sensors for multiplexed analysis. They present undisputed advantages such as robustness, reliability, high sensitivity and low power consumption.
This lecture will provide an overview of the different types of Silicon Photonic biosensors operating in a label-free scheme under the evanescent wave mechanism, including most relevant configurations as interferometers, micro-ring resonators, photonic crystals, and subwavelength waveguides based on, among others. The working principle, design, fabrication and performance of each sensor type will be discussed. We will also describe the biofunctionalization techniques as well the integration in full-compact lab-on-chip photonic sensing platforms, including microfluidics and optical sub-systems for light in-coupling and read-out. The crucial aspect of the applicability of those biosensor devices for diagnostics in real environments will be shown to demonstrate their impact in Health and Society.
|11:00 – 12:00||Quantum Applications of Silicon Photonics by Professor Lorenzo Pavesi, University of Trento (Italy)|
This talk introduces the use of Silicon Photonics as a platform to quantum photonics. After a brief introduction to the quantum states of light, I will introduce the preferred methods to generate entangled photon states or heralded single photons in silicon photonics. Then few examples of quantum circuits will be discussed: a chip size quantum random number generator for secure quantum communication, an integrated source of heralded single photons for the sensing in the MIR and an on-chip photonic molecule.
|12:00 – 13:00||Silicon Single Photon Detector by Professor Angelo Gulinatti, Politecnico di Milano (Italy)|
Both academic and industrial players are looking at silicon photonics for the implementation of many quantum technologies (e.g. quantum key distribution, boson sampling, quantum gates, etc.). Indeed, the silicon photonics provides a unique combination of scalability and low losses that is needed to transform small-scale laboratory-experiments into disruptive technologies. However, the implementation of many quantum technologies requires the detection of single photons, usually with extreme challenges in terms of detection efficiency and timing jitter.
Today, the Superconducting Nanowire Single-Photon Detector (SNSPD) provides the best combination of performance. Some examples of hybrid integration in a silicon photonic platform have also been demonstrated. However, these detectors are operated at cryogenic temperatures (1 – 3 K) with obvious drawbacks in terms of cost, complexity and scalability.
Being operated at (close to) room temperature, silicon Single-Photon Avalanche Diodes (SPADs) may represent the key to make quantum technologies widely available and to bring them out of the lab. While SPADs can potentially be integrated in a silicon photonics platform they are currently coupled with silicon photonics chips through bundle of fibers.
In this presentation I will discuss the operation, the design and the state of the art of silicon SPADs. I will analyze their use in combination with silicon photonics chips and the path toward the integration of SPADs in a silicon photonics platform.