Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.0×10?3. For the inner cladding layer, the diameter is 15-17 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 24-33 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.0×10?3. For the inner cladding layer, the diameter is 15-17 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 24-33 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.5×10?3. For the inner cladding layer, the diameter is 16.5-20 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 33-40 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: In one aspect of the invention, the bend insensitive single-mode optical fiber includes a core layer and cladding layers having an inner cladding layer, a trench cladding layer and an outer cladding layer sequentially formed surrounding the core layer from inside to outside. For the core layer, the diameter is 7-7.9 ?m, and the relative refractive index difference ?1 is between 4.6×10?3 and 6.5×10?3. For the inner cladding layer, the diameter is 16.5-20 ?m, and a relative refractive index difference ?2 is between ?3×10?4 and 3×10?4. For the trench cladding layer, the diameter is 33-40 ?m, and the relative refractive index difference ?3 is between ?2.9×10?3 and ?7.3×10?3, changes in a gradient manner and increases gradually from outside to inside, where a relative refractive index difference ?32 at an outermost interface is smaller than a relative refractive index difference ?31 at an innermost interface.

Abstract: A multimode fiber including a core and a cladding. The core has a radius (R1) of 24-26 ?m, the refractive index profile thereof is a parabola, and the maximum relative refractive index difference (?1) is 0.9-1.1%. The cladding surrounds the core and includes from inside to outside an inner cladding, a middle cladding, and an outer cladding; a radius (R2) of the inner cladding is 1.04-1.6 times that of the core, and a relative refractive index difference (?2) thereof is ?0.01-0.01%; the middle cladding is a graded refractive index cladding whose radius (R3) is 1.06-1.8 times that of the core, and a relative refractive index difference thereof is decreased from ?2 to ?4; and a radius (R4) of the outer cladding is 2.38-2.63 times that of the core, and a relative refractive index difference (?4) thereof is between ?0.20 and ?0.40%.

Abstract: A multimode fiber including a core and a cladding. The core has a radius (R1) of 24-26 ?m, the refractive index profile thereof is a parabola, and the maximum relative refractive index difference (?1) is 0.9-1.1%. The cladding surrounds the core and includes from inside to outside an inner cladding, a middle cladding, and an outer cladding; a radius (R2) of the inner cladding is 1.04-1.6 times that of the core, and a relative refractive index difference (?2) thereof is ?0.01-0.01%; the middle cladding is a graded refractive index cladding whose radius (R3) is 1.06-1.8 times that of the core, and a relative refractive index difference thereof is decreased from ?2 to ?4; and a radius (R4) of the outer cladding is 2.38-2.63 times that of the core, and a relative refractive index difference (?4) thereof is between ?0.20 and ?0.40%.