RADIATION FIELD AND OPTICAL COUPLING EVALUATION USING A NEW MATHEMATICAL MODEL

The mathematical model elaborated in this paper is based on the concept of intrinsic modes in order to analyze and synthesize optical wave propagation along a non-uniform optical structure which is used in integrated optics communication as tapered optical coupler. The new mathematical model is simply developed by introducing modifications to the intrinsic integral, and its numerical evaluation illustrates the electromagnetic field distribution inside a taper thin film and also outside the waveguide constituted by the substrate and the cladding of lower refractive index. The proposed method permits efficiently tracking the behaviour of the optical waves both inside and outside the optical waveguide, and quantifying the radiation and optical coupling occurring from the taper thin film of higher refractive index to adjacent mediums until a total energy transfer; this happens at thicknesses lower than waveguide cutoff thickness of each mode. The new model can be applied to all types of tapered optical coupler, made from different optical materials and having different wedge angles.