Core-cladding boundary

Stationary (i.e. for dA/ dz = 0) localized solutions to Eq.(3.2) represent nonlinear modes in the planar waveguide and may be found in an analytical form via matching the partial solutions of Eq.(3.2) at the core/cladding boundary. The partial solutions are Jacobi elliptical function in the core and 2l rccosh — )E]/E in the cladding (the functional dependence similar to a fundamental soliton in a uniform nonlinear medium). Here is a parameter which depends on the boundary conditions. Contrary to the modes of a linear waveguide, the transverse profile of a nonlinear mode depends on the power in the mode. 

In this paper, we have used the next numerical scheme to evaluate transverse profiles of the nonlinear modes. First, continuity conditions for and dA / at the core-cladding boundary have been applied for a... 

As the light passes from one medium to another, the refracted light obeys Snell s law (see Equation 9.2). By convention, the angles used in calculating the light paths are measured from a line drawn normal to the axis of the core-clad boundary or fiber centerline. 

Figure 6.8 shows the DMA of a GI POF fabricated by interfacial-gel polymerization and another with double cladding fabricated by coextrusion (see Chapter 5). The attenuation of the GI POF fabricated by coextrusion increases rapidly as the launching position shifts from the core center to the core-cladding boundary, whereas a slight increment in the attenuation is observed in the GI POF fabricated by interfacial-gel polymerization. This is because the structural imperfections at the core-cladding interface that are formed during the coextrusion... 

In previous studies, it was presumed that a GI POP fabricated by this process would have a refractive index distribution with a tail at the core/cladding boundary, not as steep as that prepared by the conventional batch process [50]. Therefore, the bandwidth of the GI POF obtained by dopant diffusion coextrusion would be inferior to that obtained by the batch process. However, contrary to this expectation, a GI POF without any tail prepared by the process was reported in 2007 [57]. If low-molecular-weight molecules diffuse in a radial direction, their diffusion can be expressed by Fick s diffusion equation... 

To minimize the require development program associated with the SSR, the use of a high-alloy steel for a core jacket was selected. There were two consequences of selecting this clad material on the reactor design. First, the selection of clad determines the temperature at the core/clad boundary and thus sets certain balance-of-plant design criteria. Second, given that the SSR concept is based on a monolithic right circular cylinder, a system to shut down the reactor should be located external to the core to maximize the temperature of the coolant at the exit from the reactor. 

Radiation modes with p kn, i e. 0 = n/2, are composed of plane waves at near normal incidence to the core-cladding boundary so that they are only weakly influenced by the core. Thus, radiation modes with P < kn are approximately free-space modes with ej ej and = h. The implicit conditions discussed below in Section 25-11 help facilitate this limiting condition. At the other extreme, when P = kn, i.e. 0, 0, the plane waves that form a radiation mode are at near grazing incidence and are significantly influenced by the fiber core. 

Core-cladding boundary imperfections Figure 17 Classification of intrinsic and extrinsic factors affecting the POF attenuation. 

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