US 6,275,638 B1Granted

Dispersion-shifted fiber

AssigneeSumitomo Electric Industries, Ltd.

InventorsEisuke Sasaoka, Takatoshi Kato, Yoshio Yokoyama, Akira Urano

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Abstract

A dispersion-shifted fiber includes structure configured to effectively reduce nonlinear optical effects and transmission loss caused by structural mismatching. A core region in the dispersion-shifted fiber includes an inner core and an outer core, which are both glass areas. The inner core is doped with a predetermined amount of fluorine, having an average relative refractive index difference Δn1. The outer core is disposed between the inner core and the cladding region and is doped with a predetermined amount of germanium dioxide, having an average relative refractive index difference Δn2(Δn2>Δn1), such that the viscosity ratio between the inner core and the outer core at a drawing temperature is set within a predetermined range, thereby effectively restraining structural mismatching from occurring at the boundary between these glass regions.

Claims4

Dependent claims

A dispersion-shifted fiber for propagating signal light in a 1.55-μm wavelength band, said dispersion-shifted fiber comprising:

a core region extending along a predetermined reference axis;
and
a cladding region disposed on the outer periphery of said core region,
said core region comprising:
an inner core doped with a predetermined amount of fluorine and having a first average relative refractive index difference Δn1 with respect to a predetermined region of said cladding region;
and
an outer core provided between said inner core and said cladding region, said outer core doped with a predetermined amount of germanium dioxide and having a second average relative refractive index difference Δn2 greater than said first average relative refractive index difference with respect to said predetermined region of said cladding region,
wherein a decrement Anf in said first average relative refractive index difference caused by the fluorine doping in said inner core and an increment Δng in said second average relative refractive index difference caused by the germanium dioxide doping in said outer core have the following relationship:
0.05·Δng≦nf≦0.7·Δng.

6 more elements

Dependencies are inferred from the claim text.