Analysis of the nonlinear coaxial coupler

The authors present an analysis of the nonlinear properties in the coaxial fiber coupler. Two approaches are used, numerical beam propagation calculations in the radially symmetric waveguide and analysis of the coupled equations describing the interaction of the local modes. The two methods are compared and the region of validity of the local node analysis is then determined. They examine in detail the critical power condition for this structure and show how the design considerations to achieve this conditions can be understood. >