Reduced Diameter Optical Fiber and Manufacturing Method

The invention relates to an optical fiber 1 comprising a core 2 and a cladding 3 surrounding the core 2 and having an outer diameter of 125 μm, the optical fiber 1 comprising a cured primary coating 4 directly surrounding the cladding 3 and a cured secondary coating 5 directly surrounding the cured primary coating 4, said cured primary coating 4 having a thickness t1 between 10 and 18 μm and an in-situ tensile modulus Emod1 between 0.10 and 0.18 MPa, said cured secondary coating 5 having a thickness t2 lower or equal to 18 μm and an in-situ tensile modulus Emod2 between 700 and 1200 MPa, wherein said first and second thicknesses and said first and second in-situ tensile moduli satisfy the following equation: 4%