Patent ID: 7519255

Claim:
An optical fiber, comprising: an inner core portion having a first refractive index; an outer core layer formed on an outer circumference of the inner core portion, the outer core layer having a second refractive index lower than the first refractive index; and a cladding layer formed on an outer circumference of the outer core layer, the cladding layer having a third refractive index higher than the second refractive index and lower than the first refractive index, wherein an outer diameter of the inner core portion is enlarged, the second refractive index decreased, and a center core portion is formed at a center of the inner core portion, with a refractive index lower than the first refractive index, so that an effective core area is increased while maintaining a wavelength dispersion and bending loss, wherein the wavelength dispersion is 12 ps/nm/km to 22 ps/nm/km at a wavelength of 1,550 nanometers, the bending loss is equal to or smaller than 15 dB/m when the optical fiber is wound 16 times with a diameter of 20 millimeters at a wavelength of 1,550 nanometers, the effective core area is 140 μm 2 to 200 μm 2 at a wavelength of 1,550 nanometers, and a dispersion slope is equal to or smaller than 0.066 ps/nm 2 /km.