The invention relates to a low-attenuation and large-effective-area single-mode
optical fiber. The single-mode
optical fiber comprises a core layer and wrapping
layers and is characterized in that the
radius r1 of the core layer is 4.8 micrometers-6.5 micrometers, and the relative
refraction index
delta1 of the core layer is 0.10%-0.24%; the core layer is wrapped with the inner wrapping layer, the sunk inner wrapping layer, the transitional outer wrapping layer and the outer wrapping layer in sequence from inside to outside; the
radius r2 of the inner wrapping layer of the
optical fiber is 8.5 micrometers-15 micrometers, the relative
refraction index
delta2 of the inner wrapping layer of the optical
fiber is -0.3%--0.05%, the
radius r3 of the sunk inner wrapping layer is 14 micrometers-22 micrometers, the relative
refraction index
delta3 of the sunk inner wrapping layer is -0.45%--0.2%, the radius r4 of the transitional outer wrapping layer is 35 micrometers-50 micrometers, and the relative refraction index delta4 of the transitional outer wrapping layer is -0.25%--0.05%; the outer wrapping layer is a pure
silica glass layer. The attenuation parameter of the optical
fiber is decreased; through reasonable design of
all fiber core layer sections of the optical
fiber, the optical fiber has an effective area larger than or equal to 100 square micrometers. The overall performance parameters of cutoff
wavelength, bending loss and chromatic dispersion of the optical fiber are good in an application
wave band, and a multilayer stepped sunk wrapping layer structure is adopted for the section of the optical fiber and well reduces the bending loss of the optical fiber.