Impact of linear coupling on nonlinear phase noise in two-core fibers

•The nonlinear phase noise is affected by the linear coupling in a two-core fiber.•The linear coupling among fiber cores can reduce the nonlinear phase noise.•The nonlinear phase shift variance is reduced at distance of the coupling length.•Only at the coupling length occurs the reduction of nonlinear phase noise.

We study the effect of linear coupling on nonlinear phase noise in two-core fibers (TCFs). Considering the elementary TCF switching process, we demonstrate reduction of nonlinear phase noise in the propagation of optically amplified pulses through TCFs. Our results show that the reduction occurs just when the first maximum transfer of optical power is carried out between the TCF cores.