Soliton Dynamics in a Semilinear Dual Core Bragg Grating System with Phase Mismatch

This thesis is concerned with the dynamics of Bragg grating solitons in a linearly coupled dual-core system, where Bragg gratings are written on both cores with a phase mismatch, and one core has Kerr-type nonlinearity, while the other is linear. The investigation starts with the derivation of the mathematical model, which describes the present system using nonlinear coupled-mode theory. Phase mismatch between the gratings has been taken into account by considering the random phase shifts in the gratings. The existence of Bragg grating solitons with zero-velocity (quiescent solitons) and non-zero velocities (moving solitons) is investigated by systematic linear spectrum analysis. In the case of quiescent solitons, the system's linear spectrum changes significantly depending on the zero and non-zero values of the relative group velocity in the linear core c. When c=0, the linear spectrum shows three disjoint bandgaps, and stationary solutions of the quiescent gap solitons exist in all bandgaps. However, only the central gap contains the stationary solutions of quiescent gap solitons for c not equal to 0. The maximum frequency detuning limit within which stationary solutions of quiescent gap solitons may reside is found in an analytical form. The edge of the central bandgap always increases with increasing values of phase mismatch, and remains independent of coupling coefficient, under the maximum phase mismatch condition. In the maximum phase mismatch condition, no stationary solutions of quiescent gap solitons exist in both upper and lower gaps, as both upper and lower gaps are merged with the upper and lower branches of the central gap, respectively

Additional file 1: of Evaluation of medicines dispensing pattern of private pharmacies in Rajshahi, Bangladesh

Questionnaire for clients and Questionnaire for drug sellers. (DOCX 17 kb