US 7,321,711 B2
Optical fiber and optical transmission line and optical communication system including such optical fiber
Naomi Kumano, Chiyoda-ku (Japan)
Assigned to The Furukawa Electric Co., Ltd., Tokyo (Japan)
Filed on Sep. 18, 2006, as Appl. No. 11/522,315.
Application 11/522315 is a division of application No. 11/022817, filed on Dec. 28, 2004, granted, now 7,123,803.
Application 11/022817 is a division of application No. 10/365613, filed on Feb. 13, 2003, granted, now 6,856,744.
Claims priority of provisional application 60/391948, filed on Jun. 28, 2002.
Claims priority of provisional application 60/396737, filed on Jul. 19, 2002.
Claims priority of application No. 2002-035526 (JP), filed on Feb. 13, 2002; application No. 2002-057482 (JP), filed on Mar. 04, 2002; application No. 2002-214742 (JP), filed on Jul. 24, 2002; and application No. 2002-337107 (JP), filed on Nov. 20, 2002.
Prior Publication US 2007/0009218 A1, Jan. 11, 2007
Int. Cl. G02B 6/16 (2006.01)
U.S. Cl. 385—123  [385/126] 22 Claims
OG exemplary drawing
 
1. An optical fiber comprising a core and cladding, characterized by:
a dispersion “D” of not less than 2 ps/nm/km and not more than 8 ps/nm/km (2≤D≤8) over a wavelength range of 1400 to 1700 nm and,
at least one extreme value of dispersion within said wavelength range,
the optical fiber further comprising:
a plurality of glass layers inside of the cladding having a reference refractive index, wherein
one of two adjacent layers differs in composition from the other,
first, second, third and fourth layers from the center to outside have relative refractive index differences of Δ1, Δ2, Δ3 and Δ4 from said reference refractive index of said cladding (0), respectively, and satisfy the following condition, Δ134>0Δ2.