Optical Transmission Stability of Hybrid Sol–Gel Silica/Electrooptic Polymer Waveguide Modulators

We report the optical transmission stability of polymeric electrooptic (EO) modulators with hybrid sol-gel silica/EO polymer waveguides. Waveguide transitions between the passive sol-gel silica core and the active EO polymer core are performed with gradual refractive index changes using gray-scaled photobleaching and a tapered structure; these transitions are adiabatic. The three-dimensional beam propagation method showed stable waveguiding in the waveguide as long as the index of the EO polymer core is higher than that of the sol-gel core. The optical transmission for an optical input power of 30 mW at a wavelength of 1550 nm does not change for >;1200 h.