| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical fiber which is suitably used as an optical transmission path of an optical communication system and can improve an OSNR. <P>SOLUTION: In an optical fiber which has a core portion and a cladding portion, when an effective cross section is represented by Aeff and a mode field diameter is represented by MFD, a k value represented by k=4Aeff/(πMFD<SP POS="POST">2</SP>) is 1.08 or more, wavelength dispersion is +19.0 ps/nm/km or more and +21.9 ps/nm/km or less, and the mode field diameter MFD is 10.3 μm or more and 13.0 μm or less, at a wavelength of 1,550 nm. When a position in the radial direction of which a refractive index becomes the minimum value N<SB POS="POST">1</SB>in the core portion is represented by r<SB POS="POST">1</SB>, a position in the radial direction of which a refractive index becomes the maximum value N<SB POS="POST">2</SB>in the core portion is represented by r<SB POS="POST">2</SB>, and a radius of the core portion is represented by r<SB POS="POST">3</SB>, the relationship becomes r<SB POS="POST">1</SB><r<SB POS="POST">2</SB><r<SB POS="POST">3</SB>, R=r<SB POS="POST">3</SB>/r<SB POS="POST">2</SB>is more than 1.0 and 5.4 or less, and a specific refractive index difference Δ<SB POS="POST">12</SB>between the maximum value N<SB POS="POST">2</SB>and the minimum value N<SB POS="POST">1</SB>of the refractive index in the core portion is 0.05% or more. <P>COPYRIGHT: (C)2013,JPO&INPIT |
