Raman induced destabilisation of asymmetric coupled solitary waves in nonlinear twin-core fibres

• Published in: Optics communications Vol. 218; no. 4; pp. 255 - 271
• Main Authors: Ingledew, Georgina, Smyth, Noel F., Worthy, Annette L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2003; Elsevier Science
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Integrated optics. Optical fibers and wave guides; Nonlinear optics; Optical and optoelectronic circuits; Optical solitons; nonlinear guided waves; Optics; Physics; Propagation, scattering, and losses; solitons; Raman scattering; Soliton; Stimulated raman scattering; cars; Twin-core fibre; 42.65.−k; Twin-core fibre; Raman scattering; 42.65.Tg; 42.65.Dr; Soliton; 42.81.Qb; Nonlinear optics; 42.81.Dp; Optical fibers; Solitary wave; Nonlinear equations; Pulse propagation; Theoretical study; Schroedinger equation
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/S0030-4018(03)01206-9

The evolution of pulses in both single core fibres and in nonlinear fibre couplers when the effect of Raman scattering is included is studied using an approximate technique based on conservation and moment equations. It is found that in order to obtain good agreement with numerical solutions, the effect of the dispersive radiation shed by the pulses as they evolve must be included. The dominant contribution of Raman scattering to this shed radiation is shelves of low frequency radiation lying behind the pulses. Indeed it is found that these shelves of radiation are the main effect driving the evolution of the pulses. The most dramatic effect of the mass, momentum and energy shed by the pulses to these shelves is the de-stabilisation of the asymmetric coupled solitary wave state in a nonlinear fibre coupler, which corresponds to the loss of the switching characteristics of the coupler.