Simple method for calculating the optical attenuation coefficient of a corrugated waveguide

An analysis is made of the method for the calculation of the attenuation coefficient of waves traveling in a strongly corrugated waveguide. The calculation method is based on the concept of zigzag propagation of light in the waveguide. The problem of selection of an unperturbed waveguide is considered. It is reported that the proposed method gives correct results for corrugation depths in the range 0 < 2σ < 0.5λ_w where 2σ is the corrugation depth and λ_w is the wavelength of light in the waveguide.