Modulation Instabilities in Asymmetric Fiber Coupler

Abstract

We study modulation instability (MI) in an asymmetric two-core fiber coupler. The analysis is performed for the MI gain and MI bandwidth. Effects of the parameters, input power and nonlinear coefficients on the MI are investigated. The results show that input power and nonlinear coefficients of two cores influence the MI gain and MI bandwidth. When nonlinear coefficients of two cores are both negative, better modulation stability can be obtained than other situations. In particular, if the negative nonlinear coefficients are equal, the modulation instabilities will not appear.