TRENCH-ASSISTED MULTICORE FIBER STRUCTURE WITH INHOMOGENEOUS TRENCH FOR REDECING CUTOFF WAVELENGH

摘要

The present invention discloses a structure of an optical fiber for increasing a transmission capacity per unit area by reducing a gap between cores of a multicore optical fiber. The most significant feature of the present invention is that it is possible to increase the cut-off wavelength of the core by making the refractive index of the trench surrounding the center core lower than the refractive index of the trench surrounding the outer core in the trench type multicore optical fiber including 7 cores. Also, the crosstalk between the center core and the outer core is designed to be very low. Therefore, we optimized the factors that limit the space efficiency by ensuring that the spacing between the cores limited by the crosstalk after the constant distance transmission is larger than the spacing between the cores limited by the increase of the blocking wavelength. According to the present invention, by replacing the single mode optical fiber with the inventive multi-core optical fiber, it is possible to maximize the effect of increasing the transmission capacity per unit area while using the modulation scheme used in the conventional single mode optical fiber, A large-capacity optical transmission system applicable to an optical network can be economically implemented.;