Optical device having structural and refractive index gradation, and method of fabricating the same

A method of forming a waveguide structure, comprising:

• expelling plasma from an applicator having a head toward a plurality of grating structures formed on a substrate, the plasma formed at atmospheric pressure in the head;
• depositing a layer over the plurality of grating structures by vaporizing a precursor with the plasma formed in the head;
• removing portions of the layer using a plasma from the applicator at atmospheric pressure to form a surface profile of the layer;
• and
• etching the plurality of grating structures through the layer.

A method of forming a waveguide structure, comprising:

• expelling plasma from an applicator having a head toward a substrate, the plasma formed at atmospheric pressure in the head;
• depositing one or more refractive layers over the substrate by vaporizing a precursor with the plasma formed in the head;
• depositing an overlayer on the one or more refractive layers;
• and
• forming a refractive grating structure by etching the one or more refractive layers through the overlayer.

A method of forming a waveguide structure, comprising:

• expelling plasma from an applicator having a head toward a plurality of grating structures formed on a substrate, the plasma formed at atmospheric pressure in the head;
• depositing a layer over the plurality of grating structures by vaporizing a precursor with the plasma formed in the head;
• and
• removing portions of the layer using a plasma from the applicator at atmospheric pressure to form a surface profile of the layer, the surface profile having a surface angle.