Optical fiber for preserving plane of polarization

摘要

An optical fiber (10) for preserving plane of polarization including a core (11); and a clad (12) disposed so as to surround the core, wherein the mode field diameter non-circularity ratio of the optical fiber which is calculated according to the equation: <DF>MFD non-circularity ratio (%)=Ma - Mb DIVIDED <SQRT>Ma<2> + Mb<2> DIVIDED 2</SQRT> x 100 </DF> (where MFD indicates a mode field diameter, and Ma is the maximum value and Mb is the minimum value of the mode field diameter, respectively, in a wavelength region of light used), is about 3.2% or less. The connection loss of the optical fiber may be decreased to about 0.13 dB or less. <IMAGE>