single mode fiber optic, optical box, and fiber optic system for commuter residence (ftth)

摘要

single-mode optical fiber. the present invention relates to a single-mode optical fiber which includes, from the center to the periphery, a central core, an intermediate shell, a depression and an external optical shell. the central core has a radius r ~ 1 ~ and a positive index difference 30 n ~ 1 ~ with the optical shell; the intermediate shell has a radius r ~ 2 ~ and a positive index difference 30 n ~ 2 ~ with the optical shell, where 30 n ~ 2 ~ is less than the index difference 30 n ~ 1 ~ from the core. the depression has a radius r ~ 3 ~ and a negative index difference 30 n ~ 3 ~ with the optical shell. the optical fiber has a modal field diameter (mfd) between 8.6 pm and 9.5 pm at a wavelength of 1310 nanometers, and for a wavelength of 1550 nanometers, the fiber has less curvature losses than 0.15 x 10 ^ -3 ^ db / curve for a radius of curvature of 5 mm and a cable cut-off wavelength of less than or equal to 1260 nanometers, measured as the wavelength at which the attenuation of the lp11 mode is greater than or equal to 19.3 db after propagation through twenty-two meters of fiber. this fiber can be used in a difficult environment, such as miniaturized optical boxes.