Optical waveguide type optical modulator and production method therefor

Abstract

There is provided a high performance optical waveguide type optical modulator with excellent long term reliability, in which contamination of the buffer layer in a forming process of a signal field adjustment region on the buffer layer by a lift-off method or an etching method, is prevented and DC drift thus suppressed. The optical waveguide type optical modulatorcomprises a substratehaving an electro-optic effect, optical waveguidesformed on the surface of this substratea traveling-wave type signal electrodeand ground electrodeswhich are provided on the substrateand control a lightwave, and a buffer layerprovided between the electrodesand the optical waveguidesand furthermore, a dielectric layeris provided on the entire surface of the buffer layeron the side of the electrodesand a signal field adjustment regionwhich has a wider width than that of the traveling-wave type signal electrodeand is made of a material with a higher refractive index than that of the dielectric layeris formed between the dielectric layerand the traveling-wave type signal electrode