Blog

  • Multimode Photonics Workshop 2022
    Discover how controlling self-organization phenomena in multimode photonics systems is the keystone for the next generation of internet and computing technologies. 22 – 25 August 2022 At Department of Information Engineering, Electronics, and Telecommunications, Sapienza University of Rome, Via Eudossiana Read More …
  • Thermalization of orbital angular momentum beams in multimode optical fibers
    We report on the thermalization of light carrying orbital angular momentum in multimode optical fibers, induced by nonlinear intermodal interactions. A generalized Rayleigh-Jeans distribution of asymptotic mode composition is obtained, based on the conservation of the angular momentum. We confirm Read More …
  • Multimode soliton collisions in graded-index optical fibers
    In this work, we unveil the unique complex dynamics of multimode soliton interactions in graded-index optical fibers through simulations and experiments. By generating two multimode solitons from the fission of an input femtosecond pulse, we examine the evolution of their Read More …
  • Statistical mechanics of beam self-cleaning in GRIN multimode optical fibers
    Since its first demonstration in graded-index multimode fibers, spatial beam self-cleaning has attracted a growing research interest. It allows for the propagation of beams with a bell-shaped spatial profile, thus enabling the use of multimode fibers for several applications, from Read More …
  • Multiphoton ionization of standard optical fibers
    Atoms ionization by the simultaneous absorption of multiple photons has found applications in fiber optics, where it leads to unique nonlinear phenomena. To date, studies of the ionization regime have been limited to gas-filled hollow-core fibers. Here, we investigate multiphoton Read More …
  • Helical plasma filaments from the self-channeling of intense femtosecond laser pulses in optical fibers
    We experimentally and numerically study the ignition of helical-shaped plasma filaments in standard optical fibers. Femtosecond pulses with megawatt peak power with proper off-axis and tilted coupling in the fiber core produce plasma skew rays. These last for distances as Read More …
  • Femtosecond nonlinear losses in multimode optical fibers
    Multimode optical fibers are attracting a growing interest for their capability to transport high-power laser beams, coupled with novel nonlinear optics-based applications. However, optical fiber breakdown occurs when beam intensities exceed a certain critical value. Optical breakdown associated with irreversible Read More …
  • Multimode solitons in step-index fibers
    We experimentally generate multimode solitons in step-index fibers, where nonlinearity compensates for both chromatic and modal dispersion. These solitons are subject to Raman self-frequency shift, and their energy is gradually transfered to the fundamental fiber mode. We compare multimode soliton Read More …
  • Spatiotemporal beam self‑cleaning for high‑resolution nonlinear fuorescence imaging with multimode fber
    Beam self-cleaning (BSC) in graded-index (GRIN) multimode fbers (MMFs) has been recently reported by diferent research groups. Driven by the interplay between Kerr efect and beam self-imaging, BSC counteracts random mode coupling, and forces laser beams to recover a quasi-single Read More …
  • Conditions for walk-off soliton generation in a multimode fiber
    It has been recently demonstrated that multimode solitons are unstable objects which evolve, in the range of hundreds of nonlinearity lengths, into stable single-mode solitons carried by the fundamental mode. We show experimentally and by numerical simulations that femtosecond multimode Read More …
  • Experimental observation of self-imaging in SMF-28 optical fibers
    Spatial self-imaging, consisting of the periodic replication of the optical transverse beam profile along the propagation direction, can be achieved in guided wave systems when all excited modes interfere in phase. We exploited material defects photoluminescence for directly visualizing self-imaging Read More …
  • 3D time-domain beam mapping for studying nonlinear dynamics in multimode optical fibers
    Characterization of the complex spatiotemporal dynamics of optical beam propagation in nonlinear multimode fibers requires the development of advanced measurement methods, capable of capturing the real-time evolution of beam images. We present a new space–time mapping technique, permitting the direct Read More …
  • Singlemode spatiotemporal soliton attractor
    January 29th, 2021 Experimental and numerical studies of spatiotemporal femtosecond soliton propagation over up to 1 km spans of parabolic graded-index (GRIN) fibers reveal that initial multimode soliton pulses naturally and irreversibly evolve into a singlemode soliton. This is carried Read More …
  • Managing Self-Phase Modulation in Pseudolinear Optical Transmission Systems
    January 13th, 2021 We propose a new semi-analytical model, describing the bandwidth evolution of pulses propagating in dispersion managed (DM) transmission systems using multimodal graded-index fibers (GRIN) with parabolic index. The model also applies to monomodal fiber DM systems, representing Read More …
  • Giving light a new twist: rainbow spiral emission
    October 1st, 2020 We demonstrate a new practical approach for generating multicolour spiral-shaped beams. It makes use of a standard silica optical fibre, combined with a titled input laser beam. The resulting breaking of the fibre axial symmetry leads to Read More …
  • Upconversion luminescence in optical fibers
    September 25th, 2020 We experimentally demonstrate a previously unforeseen nonlinear effect in optical fibers: up-conversion luminescence generation excited by multiphoton absorption of femtosecond infrared pulses. We directly estimate the average number of photons involved in the up-conversion process, by varying Read More …
  • Distributed Kerr Lens Mode-Locking in Multimode Fiber Laser
    July 20th, 2020 We introduce a mechanism of stable spatiotemporal soliton formation in a multimode fiber laser. This is based on spatially graded dissipation, leading to distributed Kerr-lens mode locking. Our analysis involves solutions of a generalized dissipative Gross-Pitaevskii equation. Read More …
  • Nonlinear beam self-imaging
    May 14th, 2020 Beam self-imaging in nonlinear graded-index multimode optical fibers is of interest for many applications, such as implementing a fast saturable absorber mechanism in fiber lasers via multimode interference. We obtain a new exact solution for the nonlinear Read More …
  • High-energy soliton fission
    May 2nd, 2020 The process of high-energy soliton fission is experimentally and numerically investigated in a graded-index multimode fiber. Fission dynamics is analyzed by comparing numerical observations and simulations. A novel regime is observed, where solitons produced by the fission Read More …
  • Online school on: Machine learning photonics
    Online school on: Machine learning photonics Lake Como School of Advanced Studies Dates: March 15-19, 2021 The school brings together experts in emerging photonic technologies, machine learning techniques, and fundamental physics who will share with young researchers their knowledge and Read More …