OPTIMIZATION OF PARAMETERS OF INTEGRATED OPTICAL WAVEGUIDES BASED ON THIN-FILM SOL-GEL STRUCTURES BY USING MATHEMATICAL MODELLING Article Aliev S.A., Pakhlavonova K.D., Ravin A.R., Trofimov N.S., Chekhlova T.K. Journal of Physics: Conference Series. Institute of Physics Publishing. Vol. 1439. 2020.