Analysis of optical waveguide structure using beam propagation method for optical wireless communications

Radiation scattered from a parabolic index planar waveguide with the insertion of metal strip at the centre is analyzed to design the photonic antenna, which transfers the energy from waveguide to free space, using beam propagation method (BPM). This technique allows the interpretation of the metal strip as scattering element of the underlying waveguide mode and radiating sources for the diffracted fields. The parabolic index planar waveguide with the insertion of metal strip with high refractive index value is evaluated and often explicit formulas for the radiating parameters of photonic antennas. The framework allows separation of the effects of the metal strip insertion with high refractive index value and the effects of the specific size of the metal strip element. A straightforward analogy between the effects of the metal strip element´s refractive index value, shape and the behaviour of photonic antenna systems allow a clear and sensitive understanding of the effects of metal strip on the directionality of waveguide coupled radiation. The results covered only TE modes and it is possible to achieve high directional photonic antennas in the range of optical wireless frequencies. The results are obtained for various operating wavelengths of parabolic index waveguide structure with power distribution along z-direction and the efficient wavelength is proposed for photonic antenna