Patent ID: 6813430
Filing Date: 2004-11-02
Classification: G02B

Abstract:
A dispersion-compensating optical fiber wherein,a core and a cladding provided around an outer periphery of said core are provided, said core is provided with a central core portion having a refractive index higher than said cladding, an intermediate core portion provided around an outer periphery of said central core portion having a refractive index lower than said cladding, and a ring core portion provided around an outer periphery of said intermediate core portion having a refractive index higher than said cladding, at a wavelength of 1.55 &mgr;m, chromatic dispersion is âˆ’40 ps/nm/km or less and âˆ’65 ps/nm/km or more, chromatic dispersion slope is negative, effective area is 18 &mgr;m2 or more, bending loss is 50 dB/m or less, and a cutoff wavelength is provided that allows substantially single-mode propagation, when combined with a single-mode optical fiber for transmission in which, at a wavelength of 1.55 &mgr;m, effective area is 40 &mgr;m2 or more, chromatic dispersion is positive, and a cutoff wavelength is provided that allows substantially single-mode propagation to form a hybrid transmission line, chromatic dispersion of the hybrid transmission line is âˆ’0.5 ps/nm/km or more and +0.5 ps/nm/km or less at a used wavelength band over a continuous range of at least 0.06 &mgr;m or more selected from a wavelength range of 1.45-1.63 &mgr;m, and when radii and relative refractive index differences of the central core portion, the intermediate core portion and the ring core portion based on the cladding are expressed as (a,&Dgr;1), (b,&Dgr;2) and (c,&Dgr;3), Respectively, conditions of (A) through (D) below are satisfied: (A) 0.95&lE;&Dgr;1&lE;1.35; (B) âˆ’3.5&lE;V2/V1<0 and 0.5&lE;V3/V1&lE;4.5 when V1=&Dgr;1, V2=&Dgr;2Ã—{(b/a)2âˆ’1} and V3=&Dgr;3Ã—{(c/a)2âˆ’(b/a)2}; (C) &agr;, expressed with &agr;=âˆ’y{xâˆ’1}/&Dgr;1, is such that 0.10&lE;&agr;&lE;0.45 when x=C-band, y=&Dgr;3/&Dgr;2; and, (D) the value resulting from dividing chromatic dispersion slope at a wavelength of 1.55 &mgr;m by chromatic dispersion is 0.0025 nmâˆ’1 or more and 0.0035 nmâˆ’1 or less.