Titanium-indiffusion waveguides and methods of fabrication

An optical modulator structure, comprising:

• an electro-optic crystalline substrate;
• at least a pair of titanium indiffusion regions extending beneath the surface of the substrate, said titanium indiffusion regions having a crystalline structure;
• and
• deuterium disposed in said titanium indiffusion regions, said titanium indiffusion regions being substantially free of free-flowing protons.

A method for fabricating a titanium-indiffusion waveguide, said method comprising:

• disposing titanium in the desired form of the waveguide on the surface of an electro-optic crystalline substrate;
• wetting a carrier gas with deuterium oxide (D2O);
• flowing the wet carrier gas through a container containing the substrate;
• heating the substrate for a period of time to a temperature sufficient to cause the titanium to indiffuse into the substrate;
• cooling the substrate down to about room temperature;
• and
• sustaining the wet D2O environment throughout the titanium indiffusion process.

A method for fabricating an optical modulator having at least two titanium indiffusion waveguides, said method comprising:

• disposing a pair of titanium strips in the desired form of at least a pair of corresponding waveguides on the surface of an electro-optic crystalline substrate;
• wetting a carrier gas with deuterium oxide (D2O);
• flowing the wet carrier gas through a container containing the substrate;
• heating the substrate for a period of time to a temperature sufficient to cause the titanium to indiffuse into the substrate;
• cooling the substrate down to about room temperature, the wet D2O environment being sustained throughout the titanium indiffusion process;
• disposing a buffer layer over at least the titanium-indiffused portion of the substrate;
• and
• disposing electrodes on the buffer layer.