Theory and Experiment on Coupled-Waveguide Optical Modulators with Schottky Contacts

Coupled-waveguide optical modulators with Schottky contacts are analysed in two waveguide configurations, namely, in embedded-waveguide configuration and in rib-waveguide configuration. It is shown that the heterostructured embedded-waveguide device is suitable for efficient modulation and that the homostructured rib-waveguide device has fairly small modulating power per bandwidth P/Δf in spite of its simpler structure. GaAs homostructured rib-waveguide devices including those with two sections of alternating Δβ were fabricated, and optical modulation was carried out at the light wavelength of 1.06 µm.