Curved-edge optical mode converter for heat-assisted magnetic recording

A method for forming a write head, comprising:

• depositing a first waveguide layer;
• depositing a second waveguide layer adjacent to the first waveguide layer;
• applying a first mask to a substrate parallel surface of the second waveguide layer creating masked portions and exposed portions of the first and second waveguide layers;
• etching the exposed portions of the first and second waveguide layers;
• applying a second mask to the substrate parallel surface of the second waveguide layer, the second mask creating a masked section and an exposed section of the second waveguide layer;
• and
• milling the exposed section of the second waveguide layer, wherein the second layer has a cross sectional area in a plane perpendicular to the light propagation direction that increases along the light propagation direction, the cross sectional area being smaller proximate to an input coupler and larger proximate to a near field transducer (NFT) and wherein an interface between the first layer and the second layer comprises a curve.

A method for forming a write head, comprising:

• depositing a waveguide layer;
• applying a first mask to a substrate parallel surface of the waveguide layer creating a first masked portion and a first exposed portion of the waveguide layer;
• etching the first exposed portion of the waveguide layer;
• applying a second mask to the substrate parallel surface of the waveguide layer, the second mask creating a second masked portion and a second exposed portion;
• and
• milling the second exposed portion of the waveguide layer, wherein the waveguide layer has a cross sectional area in a plane perpendicular to the light propagation direction that increases along the light propagation direction, the cross sectional area being smaller proximate to an input coupler and larger proximate to a near field transducer (NFT) and wherein an interface between the first layer and the second layer comprises a curve.