Reconstruction of the Characteristics and Determination of the Parameters of a Statistical Surface Roughness from Light Scattering Data in an Integrated Waveguide in the Presence of Noise

A computer simulation is used to obtain the solution to the direct and inverse problems of the waveguide scattering of laser radiation by a stationary statistical surface roughness of the substrate of an integrated optical waveguide in the presence of additive or multiplicative white noise. It is shown that the procedure developed for processing far-field scattering data is capable of providing the necessary information on the statistical properties of the surface roughness even when the signal-to-noise ratio is very low (SNR > 1). For a given additive or multiplicative noise with SNR ≥ 1, the proposed method allows one, in the model calculations, to reconstruct the autocorrelation function with an error within 50-80% when the roughness correlation interval varies from λ/50 to 10λ (correspondingly). In this case, the correlation interval can be determined with an error no greater than 10-30%, and an rms height of the order of 1-500 Å, with an error less than 5-15%. © 2003 MAIK "Nauka/Interperiodica".