SHAPE-CHANGING COLLISIONS OF COUPLED BRIGHT SOLITONS IN BIREFRINGENT OPTICAL FIBERS

We critically review the recent progress in understanding soliton Apropagation in birefringent optical fibers. By constructing the most Ageneral bright two-soliton solution of the integrable coupled Anonlinear Schrodinger equation (Manakov inudel) we point out that Asolitons in birefringent fibers can in general change their shape after interaction due to a change in the intensity distribution among Athe modes even though the total energy is conserved. However, the Astandard shape-preserving collision (elastic collision) property of Athe (I -I- l)-dimensional solitons is recovered when restrictions are Aimposed on some of the soliton parameters. As a consequence the Afollowing further properties can be deduced using this shape-changing Acollision. (i) The exciting possibility of switching of solitons between Aorthogonally polarized modes of the birefringent fiber exists. (ii) When additional effects due to periodic rotation of birefringence Aaxes are considered, the shape changing collision can be used as a Aswitch to suppress or to enhance the periodic intensity exchange Abetween the orthogonally polarized modes. (iii) For ultra short optical soliton pulse propagation in non-Kerr Amedia, from the governing equation an integrable system of coupled Anonlinear Schrodinger equation with cubic-quintic terms is identified. AIt admits a nonlocal Poisson bracket structure. (iv) If we take into account the higher-order terms in the coupled Anonlinear Schrodinger equation then their effect on the shape changing Acollision of solitons, during optical pulse propagation, can be Astudied by using a direct perturbational approach.