Abstract: Few mode optical fibers for mode division multiplexing. The Few Mode Fiber supporting 25 or 30 LP guided modes and includes a graded index core with a ?-profile, a radius R1 (at 0 refractive index difference) between 21.5 and 27 ?m and a maximum refractive index difference Dn1 between 12.5×10?3 and 20×10?3, and an end of the ?- profile at a radius R1b, with index difference Dn1b; a trench surrounding the core with radius R3 between 30 and 42 ?m and refractive index difference Dn3 between ?15.10?3 and ?6.10?3, an intermediate depressed trench with a radius R2, with R1b<R2<R3 and a refractive index difference Dn2, with Dn3<Dn2<0, wherein: for |Dn1b?Dn2|>=0.5×10?3, Min(Dn1b, Dn2)??1.5×10?3, and for |Dn1b?Dn2|<0.5×10?3, Dn2 is between ?5×10?3 and ?3.5×10?3.