Designing waveguide filters with optical thin-film computational tools

By comparing computation results obtained with the film mode matching (FMM) method to those obtained with the Abeles optical thin-film computation met hod, we demonstrate that the Abels method may be used to compute the spectr al transmittance or reflectance of filters for waveguides. Some classical e xamples of integrated optics components are presented to check the validity of the Abeles computation method (ACM) for waveguides: an integrated Bragg reflector, an integrated narrow band-pass filter and a high-pass dichroic filter, Results obtained with the Abeles method can be very close to those obtained with the rigorous FMM method. Moreover, computation time can be di vided by a factor of 10,000 on a conventional PC. An automatic synthesis so ftware based on the ACM is then used to design an integrated gain flattenin g filter. Thus, we show that spectral filters for waveguides of arbitrary s pectral transmittance or reflectance can be designed with thin-film synthes is softwares based on the well-known Abeles method. (C) 2001 Elsevier Scien ce B.V. All rights reserved.