The Scattering Centers in Dielectric Thin Film Optical Waveguides

The properties and effects on the optical propagation loss of the scattering centers in dielectric thimn film optical waveguides are presented. Polymethyl-methacrylate, whose refractive index is n 2 =1.492 at a wavelength of λ=0.515 µm, is chosen as the material for the guide because of its excellent characteristics. The relations between the optical propagation loss of the guide and the scattering centers, which indicate the qualities of the guide, are disctussed both theoretically and experimentally. The results obtained here are as follows: the refractive index of the centers is n 1 =1.488 at λ=0.515 µm, the density function of the centers is expressed in the form N ( D )= N 0 exp (-γ D ) and the optical propagatiorn loss as α=∫ D N ( D ) Q ( D , n ,λ)d D , where D and Q ( D , n ,λ) are the diameter and the scattering cross section of the centers, respectively.