• Photonics Research
  • Vol. 9, Issue 12, 2443 (2021)
Mario Ferraro1,*, Fabio Mangini2, Mario Zitelli1, Alessandro Tonello3..., Antonio De Luca4,5, Vincent Couderc3 and Stefan Wabnitz1,6|Show fewer author(s)
Author Affiliations
  • 1Department of Information Engineering, Electronics, and Telecommunications, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy
  • 2Department of Information Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy
  • 3Université de Limoges, XLIM, UMR CNRS 7252, 123 Avenue A. Thomas, 87060 Limoges, France
  • 4Physics Department, University of Calabria, I-87036 Arcavacata di Rende, CS, Italy
  • 5CNR Nanotec-Institute of Nanotechnology, S.S. Cosenza, I-87036 Rende, CS, Italy
  • 6CNR-INO, Istituto Nazionale di Ottica, Via Campi Flegrei 34, I-80078 Pozzuoli, NA, Italy
  • show less
    DOI: 10.1364/PRJ.425878 Cite this Article Set citation alerts
    Mario Ferraro, Fabio Mangini, Mario Zitelli, Alessandro Tonello, Antonio De Luca, Vincent Couderc, Stefan Wabnitz, "Femtosecond nonlinear losses in multimode optical fibers," Photonics Res. 9, 2443 (2021) Copy Citation Text show less

    Abstract

    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 modifications of the refractive index, triggered by multiphoton absorption, has been largely exploited for fiber material micro-structuration. Here we show that, for light beam intensities slightly below the breakdown threshold, nonlinear absorption strongly affects the dynamics of a propagating beam as well. We experimentally analyze this subthreshold regime and highlight the key role played by spatial self-imaging in graded-index fibers for enhancing nonlinear optical losses. We characterize the nonlinear power transmission properties of multimode fibers for femtosecond pulses propagating in the near-infrared spectral range. We show that an effective N-photon absorption analytical model is able to describe the experimental data well.
    εn02+2n0n2|E|2gn02r2+in0αNk0|E|2N2.

    View in Article

    P=2π|E|2rdr

    View in Article

    dPdz=αN2N1PN(πa2)N1,

    View in Article

    a(z)=a0cos2(gz)+Csin2(gz).

    View in Article

    C=1pk02a04g,

    View in Article

    ε=(n0+n2|E|2+iαN2k0|E|2N2gr22n0)2,g=2n0Δrc2,(A1)

    View in Article

    1rr(rEr)+2ikEzk2r2gE+2n2n0k2|E|2E+ikαN|E|2N2E=0,(A2)

    View in Article

    E(z,r)=A(z)eσr2.(A3)

    View in Article

    4σ(σr21)Aeσr2+2ik(dAdzr2Adσdz)eσr2k2r2gAeσr2+2n2n0k2|A|2Ae3σr2+ikαN|A|2N2Ae(2N1)σr2=0.(A4)

    View in Article

    2i(12σdAdzA2σ2dσdz)kgA2σ2+2n2n0k|A|2A16σ+iαN|A|2N2A12(2N1)σ=0.(A5)

    View in Article

    2i(σdAdzAdσdz)kgA+23n2n0kσ|A|2A+iαNσ2N1|A|2N2A=0.(A6)

    View in Article

    σ=σ+iσ;A=|A|eiϕdAdz=eiϕ(d|A|dz+i|A|dϕdz),(A7)

    View in Article

    2i[(σ+iσ)(d|A|dz+i|A|dϕdz)|A|(dσdz+idσdz)]kg|A|+23n2n0k(σ+iσ)|A|3+iαN2N1(σ+iσ)|A|2N1=0.(A8)

    View in Article

    Re:2σd|A|dz2σ|A|dϕdz+2|A|dσdzkg|A|+23n2n0σk|A|3αN2N1σ|A|2N1=0,(A9)

    View in Article

    Im:2σd|A|dz2σ|A|dϕdz2|A|dσdz+23n2n0σk|A|3+αN2N1σ|A|2N1=0.(A10)

    View in Article

    d|A|dz=|A|[ddzln|σ|kgσ2|σ|2αN2(2N1)|A|2N2],(A11)

    View in Article

    d|A|dz=|A|[f(z)αN2(2N1)|A|2N2],(A12)

    View in Article

    P=2π|E|2rdr(A13)

    View in Article

    f(z)=1adadz,(A14)

    View in Article

    P(z)=π|A|2a2.(A15)

    View in Article

    dPdz=αN2N1PN(πa2)N1,(A16)

    View in Article

    P(z)=Pp{1+N12N1αNPpN10zdz[πa2(z)]N1}1N1.(B1)

    View in Article

    0zdz[πa2(z)]N1gzπ0π/gdz[πa2(z)]N1.(B2)

    View in Article

    P(z)=Pp[1+N12N1IN1αN(Ppπa02)N1z]1N1,(B3)

    View in Article

    IN=1π0πdy[cos2y+Csin2y]N,(B4)

    View in Article

    Mario Ferraro, Fabio Mangini, Mario Zitelli, Alessandro Tonello, Antonio De Luca, Vincent Couderc, Stefan Wabnitz, "Femtosecond nonlinear losses in multimode optical fibers," Photonics Res. 9, 2443 (2021)
    Download Citation