Interaction between the breather and breather-like soliton, and breather-to-soliton conversions of a variable-coefficient coupled Hirota system in an inhomogeneous optical fiber

Optical fibers are used in the optical sensing and optical fiber communication. In this paper, we investigate a variable-coefficient coupled Hirota system which describes the vector optical pulses in an inhomogeneous optical fiber. With respect to the slowly varying normalized envelopes of the electric fields, we construct the one-fold solutions which describe the two breatherlike solitons and one breather, and two-fold solutions which describe the four breather-like solitons and two breathers. We obtain the one- and two-fold breather-to-soliton conversion conditions which are both related to alpha(t) and beta(t), the coefficients of the group velocity dispersion and third-order dispersion. Based on the one-fold breather-to-soliton conversion condition, we present several types of the nonlinear waves and the corresponding relations on alpha(t) and beta(t). Interaction between the Akhmediev breather/Kuznetsov-Ma breather and breatherlike soliton is shown. Maximum amplitudes of the Akhmediev breather/Kuznetsov-Ma breather and breather-like soliton are related to delta(t), where delta(t) denotes the coefficient of the nonlinear terms corresponding to the self-phase modulation and cross-phase modulation. When alpha(t) and beta(t) meet the one-fold breather-to-soliton conversion condition, interaction between the periodic wave/anti-dark/multi-peak/M-shaped soliton and breather-like soliton is presented. Interaction between the two-Kuznetsov-Ma breather and two-breather-like soliton is shown. Maximum amplitudes of the two-Kuznetsov-Ma breather and two-breather-like soliton are related to delta(t). When alpha(t) and beta(t) meet the two-fold breather-to-soliton conversion conditions, interaction between the two-anti-dark and two-breather-like soliton is shown.

Automated summary

This study investigates a variable-coefficient coupled Hirota system describing vector optical pulses in optical fibers. Conversion conditions for breather-to-soliton are obtained, and interactions between different types of waves are presented.