| 摘要 |
<p>Provided is an extreme bending insensitive optical fiber. The optical fiber includes a core comprising a maximum refractive index difference ”n1 in the optical fiber, an inner layer comprising a refractive index difference ”n2 that is smaller than the maximum refractive index of the core and decreases in a direction away from the core, the inner layer being positioned outside the core, and a trench layer comprising an inner-circumference refractive index difference ”n3 that is smaller than the refractive index difference of the inner layer and an outer-circumference refractive index difference ”n4 that is a minimum refractive index difference in the optical fiber, the trench layer being positioned outside the inner layer, wherein a refractive index difference of the trench layer gradually decreases from an inner surface to an outer surface of the trench layer, a ratio (”n3/”n4) of the inner-circumference refractive index difference ”n3 to the outer-circumference refractive index difference ”n4 is larger than 0.6 and smaller than 1, a ratio (a+b)/b of a radius 'a' of the core and a thickness 'b' of the inner layer is less than 2.8, and the optical fiber comprises a cutoff wavelength of 1260nm or less, a bending loss ±1 of 1.0dB or less in bending by a radius of 10mm or less at a wavelength of 1550nm, and a ratio (±2/±1) of a bending loss ±2 at 1625nm to the bending loss ±1 at 1550nm being less than 2.7.</p> |
