SOLITON CONTROLLING, SWITCHING, AND SPLITTING IN NONLINEAR FUSED-FIBER COUPLERS

We propose an exactly solvable model of soliton-based pulse control th at describes the physically important situation when the soliton perio d is much longer than the length of the coupling region in a nonlinear fiber coupler. This case can occur, e.g., in fused-fiber couplers. We demonstrate that the problem of soliton interaction and switching in such a coupler can be reduced to a linear relation between the fields before and after interaction. The soliton states can be found by solut ion of two Zakharov-Shabat eigenvalue problems associated with a pair of decoupled nonlinear Schrodinger equations. Various regimes of solit on control, switching, and splitting in this model are discussed. In p articular, we show that perfect pulse switching from one arm of the co upler to the other resembles the switching of continuous waves in line ar couplers, whereas the phase-controlled switching of solitons is sim ilar to that in nonlinear directional couplers. We also describe other schemes of soliton control, including pulse compression through fusio n of two fundamental solitons.