US Patent 7483614 Optical fiber and optical device using the same

There is disclosed an optical fiber wherein an absolute value of the fourth order dispersion β4 of fourth derivative β4 of propagation constant β with respect to angular frequency ω at a mean zero dispersion wavelength λ0 in an overall length is not more than 5×10−56 s4/m and wherein a fluctuation of a zero dispersion wavelength along a longitudinal direction is not more than ±0.6 nm.