Optical apparatus and methods of manufacture thereof

Optical apparatus for evanescently coupling an optical signal across an interface between a first waveguide formed by laser inscription of a first substrate and an additional waveguide, the optical apparatus comprising:

• the first substrate, wherein the first waveguide comprises a curved section configured to provide evanescent coupling of the optical signal between the first waveguide and the additional waveguide;
• and
• the additional waveguide, wherein the additional waveguide comprises a second waveguide of a second substrate;
• the optical apparatus further comprises a further waveguide on the first substrate;
• the second substrate has a ledge-type arrangement that comprises an edge coupler;
• the first substrate has a shape that is complementary to the shape of the ledge-type arrangement of the second substrate to provide complementary coupling of the first substrate and the second substrate;
• and
• the edge coupler is configured to provide coupling between the further waveguide and the second waveguide when the first substrate and the second substrate are coupled, thereby providing coupling of an optical signal between the first waveguide and the second waveguide via the further waveguide.

A method of manufacturing an optical apparatus, the method comprising:

• providing a first substrate;
• forming a first waveguide in the first substrate by laser inscription so that the first waveguide comprises a curved section;
• providing a second substrate comprising a second waveguide;
• coupling the first substrate and second substrate together so that the curved section is configured to provide evanescent coupling of an optical signal across an interface between the first waveguide and the second waveguide;
• and
• providing a further waveguide on the first substrate;
• the second substrate has a ledge-type arrangement that comprises an edge coupler;
• the first substrate has a shape that is complementary to the shape of the ledge-type arrangement of the second substrate to provide complementary coupling of the first substrate and the second substrate;
• and
• the edge coupler is configured to provide coupling between the further waveguide and the second waveguide when the first substrate and the second substrate are coupled, thereby providing coupling of an optical signal between the first waveguide and the second waveguide via the further waveguide.

A method of manufacturing an optical apparatus, the method comprising:

• providing a first substrate;
• depositing a sacrificial layer on the first substrate;
• laser inscribing the first waveguide in the first substrate;
• removing a portion of the sacrificial layer to expose a portion of the first substrate;
• providing a further waveguide on the exposed portion of the first substrate;
• and
• providing a second substrate comprising a second waveguide;
• the second substrate has a ledge-type arrangement that comprises an edge coupler;
• the first substrate has a shape that is complementary to the shape of the ledge-type arrangement of the second substrate to provide complementary coupling of the first substrate and the second substrate;
• and
• the edge coupler is configured to provide coupling between the further waveguide and the second waveguide when the first substrate and the second substrate are coupled, thereby providing coupling of an optical signal between the first waveguide and the second waveguide via the further waveguide.