Optical waveguide element and method of fabrication thereof

A method of fabricating an optical waveguide element, comprising the steps of:

• (a) forming, on a surface of an optical waveguide layer having a ridge type channel optical waveguide and formed by epitaxial growth, an amorphous thin film whose refractive index after epitaxial growth is smaller than a refractive index of the optical waveguide layer;
• (b) reshaping the amorphous thin film such that a taper-shaped portion, which has substantially the same width as a width of a channel optical waveguide and has a thickness which increases toward an end surface, remains above at least one of a light entering end portion and a light exiting end portion of the channel optical waveguide;
• and
• (c) forming a taper type cladding layer by solid phase epitaxially growing the reshaped amorphous thin film by heating the reshaped amorphous thin film.

A method of fabricating an optical waveguide element, comprising the steps of:

• (a) forming, by epitaxial growth and on a surface of a slab type optical waveguide layer formed by epitaxial growth, a slab type cladding layer whose refractive index is smaller than a refractive index of the optical waveguide layer;
• (b) forming a taper type cladding layer by reshaping the slab type cladding layer such that a taper-shaped portion, which has substantially the same width as a width of a channel optical waveguide and has a thickness which increases toward an end surface, remains above at least one of a light entering end portion and a light exiting end portion at which the channel optical waveguide is to be formed;
• and
• (c) forming a ridge type channel optical waveguide by reshaping the slab type optical waveguide layer into a predetermined channel pattern.