An optical fiber tape having low polarization mode dispersion
characteristics and applied to a dense wavelength multiplex (DWDM)
transmission system of a transmission rate from several Gb/s to several
tens of Gb/S. We have found out that the polarization mode dispersion of
an optical fiber tape relates to the loss tangent (tan .delta.)
determined when the dynamic viscoelasticity is measured, and that
particularly, if the loss tangent of when a dispersion shift fiber is
used is made 0.080 or more and the loss tangent of when a single mode
optical fiber is used is made 0.042 or more, the polarization mode
coefficient of dispersion (PMD) is reduced to 0.3 ps/ km preferable to
realize a DWDM transmission system.