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Multimode Photonics

Discover how controlling self-organization phenomena in multimode photonics systems is the keystone for the next generation of internet and computing technologies

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CIVIS focus area
Digital and Technological transformation
Open to
  • Phd
Field of studies
  • Computer Science and IT
  • Engineering & Technology
  • Natural Sciences and Mathematics
  • Short-term
Course dates
22 - 25 August 2022

The recent use of multimode fibers within ultrafast lasers unveils a rising paradigm, where nonlinear processes such as beam self-cleaning can promote a wealth of spatiotemporal pulses and patterns, overcoming the adverse effects of the intermodal dispersion. The development of the next generation of telecommunication systems and ultrashort fiber laser sources will lead to a huge versatility in terms of system capacity, spectral coverage, and energy scalability, thus meeting an extended range of applications.

However, the fundamental understanding of nonlinear multimode propagation is still in its infancy. In this meeting, we will combine the complementary expertise from national and international leading scientists in optical fiber transmission, optical frequency combs and lasers, covering experimental, numerical, and theoretical aspects.

Multimode fiber systems will open the way to new spatial division multiplexing and laser architectures, whose performance can be developed in an unequalled manner, in particular in terms of information capacity, optical power and spectral coverage. New mode-locking techniques, as well as the generation of frequency combs that can be transposed in the infrared as well as in the visible range, will be exposed. Novel intracavity control schemes and numerical simulation techniques based on artificial intelligence will be discussed, which will permit to unbridle the full potential of nonlinear spatiotemporal coupling among different degrees of freedom.

Multimode (MM) optical fibers were used in optical telecommunications in the early 1980s, but considering the poor output radiation quality that resulted from the large number of propagation modes involved, they were mostly replaced by single-mode (SM) fibers. In particular, it has long been thought that ultrashort optical pulses required single transverse mode propagation in optical fibers and waveguides, owing to the expected impact of the large intermodal dispersion. Surprisingly, MM fibers are now experiencing a huge revival of research interest.

Indeed, recent advances are building up a new paradigm, in which well-designed nonlinear coupling processes in multimode (MM) waveguides, such as beam self-cleaning can promote the self-formation of spatiotemporal pulses and patterns, thus overcoming the adverse effects of the intermodal dispersion.

The increased interest for MM fibers is due in great part to their power upscaling possibilities, for which standard single-mode fibers cannot compete. Furthermore, novel efficient wavelength conversion processes specific to MM fibers pave the way for extending the wavelength range of coherent sources, which could become an alternative to supercontinuum generation in single mode (SM) fibers.

MM fibers have become again the object of active research, from fundamental prospects to the practical means to overcome the reached limits of single-mode fiber systems. Likewise in the telecom domain, MM fibers are considered as an efficient way to circumvent the current transmission limit of SM fibers and potential capacity crunch of our internet, by using spatial-domain multiplexing (SDM) as a potent signal multiplexing layer. SDM is a challenging technology that requires fine modal control and currently drives significant research efforts from high-tech companies.

To summarize, two major keys appear to enable this novel MM fiber paradigm: nonlinearity and control. Nonlinearity drives self-organization possibilities, such as beam self-cleaning, spatiotemporal optical solitons, and enhanced wavelength coverage. Nonlinearity implies high peak power, which is scalable through the design of optical waveguides. Control refers to the way a beam can be launched with a specific modal composition, selected, reshaped, and analyzed.

In the workshop, talks will describe how nonlinearity and control can be combined, in what we believe to be the most relevant physical system: the multimode fiber laser. In particular, the use of artificial intelligence could be the key for tackling the inherent complexity of using these two enabling keys, and unveil a wide range of new spatiotemporal dynamics with a high potential of applications. Talks shall address these issues and prospects from experimental, numerical and theoretical standpoints, benefitting from the complementarity expertise of top national and international researchers.

Presentations will review spatiotemporal nonlinear optics within multimode comb sources, fiber lasers and transmissions, considering the crossroad between fundamental and applied problems belonging to different research areas. The workshop will combine experiments with their analytical/numerical analysis: such a symbiotic description will provide appropriate interpretations of the experimental results, and inspire new ideas with the scope of identifying, explaining and controlling the key mechanisms of beam shaping and control in dissipative fiber lasers and comb sources, and transmission structures.

Self-organization effects in multimode systems involve fundamental aspects of nonlinear science, complexity, dissipative systems, optical pattern formation and their associated concepts and tools. From the application point of view, breakthrough advances are expected in high-power beam delivery from a fiber laser oscillator, and subsequent applications such as lidar or supercontinuum generation.

Main topics addressed

  • Multimode optical frequency comb sources
  • Spatial division multiplexing transmissions
  • Machine learning photonics
  • Multimode fiber lasers
  • Biomedical multi-photon nonlinear imaging
  • Fiber lasers for cultural heritage preservation
  • Green photonics
  • Nonlinear science and complex systems

Learning outcomes

Students will gain a strongly interactive learning experience of the state-of-the-art and applications for an emerging research field, jointly with the top experts at the world level.

Duration of the course: 4 days Format: Physical
Individual workload: 8 hours Location: Rome, Italy
CIVIS scholarships: 15 Language: English
Contact point: ECTS: 1*

*Recognition of ECTS depends on your home university. 


The CIVIS Workshop "Multimode Photonics" is organised into 4-morning sessions (9:00-13:00) and 4-afternoon sessions (15:00-19:00). It involves a series of seminars by national and international speakers, world leaders in the field and local stakeholders in Italy. The Workshop is hosted by Sapienza Università di Roma and it will take place over four days. 


This CIVIS workshop is open to PhD students at one of CIVIS member universities, to be selected by means of an application procedure.

The workshop is also open to applications from PhD students at other universities. CIVIS Students are entitled to apply for one of the 15 studentships to cover travel and accommodation costs. Registration to the workshop is free for CIVIS students, while it amounts to 350 euros for other students. Registration payment instructions will be sent to the selected students. Registration fees include coffee breaks, lunches, social dinner and excursions in Rome.

Application process

Interested students should send their CV, a motivation letter and a 1-page summary of a poster presentation (optional) by 31 May 2022 to


The course evaluation will be based on a multiple-choice questionnaire on the content of the lectures.

General Eligibility Criteria for CIVIS Courses

Applicants need to be enrolled at their home university in order to be eligible for selection and participation.  If uncertain about your status at your home university (part-time or exchange students etc) please check with your home university’s website or International Office. 

Applicants who will be receiving other Erasmus funds for the duration of the course are not entitled to funding. Participation in the course may still be possible under “zero-grant” status, but applicants should contact their home university in order to confirm this. 

A list of links and contacts for each university can be found in this Q&A.

GDPR Consent

The CIVIS alliance and its member universities will treat the information you provide with respect. Please refer to our privacy policy for more information on our privacy practices. By applying to this course you agree that we may process your information in accordance with these terms.

  • M. Zitelli, Sapienza Università di Roma, Italy: Multimode soliton dynamics
  • S. Wabnitz, Sapienza Università di Roma, Italy: Exotic multimode nonlinear optics and applications
  • C. Antonelli, Università dell'Aquila, Italy: Modelling propagation in fibers for space-division multiplexed transmission
  • M. Haelterman, Université libre de Bruxelles, Belgium: The nonlinear passive optical resonator: a historical perspective
  • V. Couderc, Université de Limoges, France: Second harmonic generation in multimode optical fibers
  • G. Genty, Tampere University, Finland: Machine learning applications to nonlinear fiber systems
  • M. Guasoni, Southampton University, UK: Four-wave mixing phenomena in multimode optical fibers
  • M. Sorel, Glasgow University, UK: AlGaAs platform for multimode nonlinear optics
  • D. Lin, Southampton University, UK: Structured light generation in multicore fiber and few-mode fiber amplifiers and lasers
  • K. Krupa, Polish Academy of Sciences, Poland: Spatiotemporal nonlinear dynamics in multimode fibers and its applications
  • A. Picozzi, Université de Bourgogne, France: Wave turbulence in multimode fibers and the role of disorder
  • D. Psaltis, EPFL, Switzerland: Imaging and computing with multi-mode fibers
  • F. Tani, Max-Planck-Institut, Germany: Spatio-temporal dynamics in hollow-core fibres
  • R. Morandotti, INRS, Canada: Multimode optics for affordable quantum technologies
  • F. Wise, Cornell University, USA: Spatiotemporal Dynamics of Multimode Optical Pulse Generation: Toward High-Performance Ultrafast Lasers
  • D. Christodoulides, University of Central Florida, USA: Optical thermodynamics of highly-multimoded nonlinear optical systems
  • A. Mafi, University of New Mexico, USA: Anderson Localization and Disordered Optical Fibers
  • S. Ramachandran, Boston University, USA: Nonlinear Optics meets Topological Photonics: Influence of Angular Momentum and Chirality on Fiber Nonlinear Optics
  • S. Babin, Russian Academy of Sciences, Russia: Spatio-spectral effects at Raman lasing in multimode and multicore fibers
  • Vilma Basilissi, Istituto Centrale per il Restauro, and Laura Rivaroli, Bologna University, ItalyOptical instruments for the study of Cultural Heritage: requirements and needs to improve the conservation field
  • M. Leonetti, Italian Institute of Technology, ItalyApplications of disordered photonics: a journey from transverse Anderson localization to analog optical computation