A multimode optical fiber, comprising an optical core and an outer optical cladding surrounding the optical core, the optical core having an α graded-index profile with α ≥ 1, α being a non-dimensional parameter that defines the index profile shape of the optical core, and the optical core having a maximal refractive index n core at its center and an outer radius R core, said optical cladding having at its outer edge a refractive index n Cl, said optical cladding comprising a region of depressed refractive index n trench, called a trench, with a negative refractive index difference Dn t = n trench - n Cl with respect to said optical cladding, said trench having a width w 3, said optical cladding also comprising a region of intermediate cladding, with a refractive index difference Dn 2 with respect to said optical cladding, said intermediate cladding having a width w 2, and being located between, and in contact with, the optical core and the trench, wherein said multimode optical fiber has a mode carrying capacity supporting propagation of at least fifty-four and at maximum sixty-eight LP modes at an operating wavelength λ op comprised between 1050nm and 1070nm, said mode carrying capacity being defined by a specific relationship between the Numerical Aperture NA = n core 2 − n Cl 2 of said optical core at said operating wavelength λ op and said optical core outer radius R core, wherein said optical core has an outer radius 24 μm ≤ R core ≤ 26 μm, a numerical aperture NA between 0.190 and 0.225 at said operating wavelength λ op, wherein said optical core, intermediate cladding and trench satisfy the criterion Cg int < 0.25, where: Cg int = 1000 Dn 2 − 3.00 + 2.21 w 2 + 0.290 w 3 + 0.365 V t Δ core + 0.12 R core − 25 4 with: R core, w 2 and w 3 expressed in microns, V t = π {( R core + w 2 + w 3) 2 - ( R core + w 2) 2} * Dn t a volume of said trench expressed in μm 2, Dn t ≥ − 5.5 × 10 − 3, Δ core = n core 2 − n Cl 2 2 n core 2 expressed in %, and Dn 2, Dn t and Δ core measured at a wavelength λ = 633nm, and wherein the value of a is between 2.01 and 2.05. said optical cladding comprising a region of depressed refractive index n trench, called a trench, with a negative refractive index difference Dn t = n trench - n Cl with respect to said optical cladding, said trench having a width w 3, said optical cladding also comprising a region of intermediate cladding, with a refractive index difference Dn 2 with respect to said optical cladding, said intermediate cladding having a width w 2, and being located between, and in contact with, the optical core and the trench, wherein said multimode optical fiber has a mode carrying capacity supporting propagation of at least fifty-four and at maximum sixty-eight LP modes at an operating wavelength λ op comprised between 1050nm and 1070nm, said mode carrying capacity being defined by a specific relationship between the Numerical Aperture NA = n core 2 − n Cl 2 of said optical core at said operating wavelength λ op and said optical core outer radius R core, wherein said optical core has an outer radius 24 μm ≤ R core ≤ 26 μm, a numerical aperture NA between 0.190 and 0.225 at said operating wavelength λ op, wherein said optical core, intermediate cladding and trench satisfy the criterion Cg int < 0.25, where: Cg int = 1000 Dn 2 − 3.00 + 2.21 w 2 + 0.290 w 3 + 0.365 V t Δ core + 0.12 R core − 25 4 with: R core, w 2 and w 3 expressed in microns, V t = π {( R core + w 2 + w 3) 2 - ( R core + w 2) 2} * Dn t a volume of said trench expressed in μm 2, Dn t ≥ − 5.5 × 10 − 3, Δ core = n core 2 − n Cl 2 2 n core 2 expressed in %, and Dn 2, Dn t and Δ core measured at a wavelength λ = 633nm, and wherein the value of a is between 2.01 and 2.05. R core, w 2 and w 3 expressed in microns, V t = π {( R core + w 2 + w 3) 2 - ( R core + w 2) 2} * Dn t a volume of said trench expressed in μm 2, Dn t ≥ − 5.5 × 10 − 3, Δ core = n core 2 − n Cl 2 2 n core 2 expressed in %, and Dn 2, Dn t and Δ core measured at a wavelength λ = 633nm, and wherein the value of a is between 2.01 and 2.05.