Composite optical waveguide structures: technology and features

The paper presents complex waveguide structures which have been fabricated on a basis of the gradient waveguide on the top of which a uniform waveguide film of high refractive index is deposited. The gradient waveguides were fabricated using the ion exchange method, whereas the uniform film with the application of the sol-gel method. The application of such a waveguide structure in the system of difference interferometer makes it possible to obtain high sensitivities of the effective refractive index against the changes of sensor layer parameters, in particular when the interference of the basic mode TM 0 with the first order mode TM 1 is applied. The paper presents the theoretical analysis of complex waveguide structures, their fabrication technology and the results of experimental studies.