Photonic integrated circuit structure
A photonic integrated circuit structure includes a substrate, a waveguide structure and a spot size converter. The waveguide structure is disposed over a surface of the substrate and has a receiving end. The spot size converter includes a concave mirror and a curved mirror. The concave mirror and the curved mirror are opposite to each other and have a common focus. The concave mirror is arranged to reflect a parallel beam from a transmitting end such that a first reflected beam is able to converge at the common focus, and the curved mirror is arranged to reflect the first reflected beam such that a second reflected beam is directed parallel to the receiving end of the waveguide structure.
1 . A method for manufacturing a spot size converter of a photonic integrated circuit, wherein the photonic integrated circuit comprises a substrate, a waveguide structure arranged on one surface of the substrate and a stack structure arranged opposite to the waveguide structure, a groove is defined between the waveguide structure and the stack structure, and the waveguide structure has a receiving end, the method comprising:
forming a curved mirror in the groove; and
forming a concave mirror above the waveguide structure, wherein the curved mirror and the concave mirror are disposed opposite to each other and have a common focus;
wherein the concave mirror is arranged to reflect a parallel beam from a transmitting end such that a first reflected beam is able to converge at the common focus, and the curved mirror is arranged to reflect the first reflected beam such that a second reflected beam is directed parallel to the receiving end of the waveguide structure,
wherein said first reflected beam is configured to propagate along a non-guided optical path before being reflected by said curved mirror into said second reflected beam, and
wherein the step of forming the concave mirror above the waveguide structure further comprises:
fully filling the groove with a removable material and covering an area above the waveguide structure and the stack structure with the removable material;
molding the removable materials according to the common focus so that one upper surface of the removable materials has a curve;
depositing another metal layer on the upper surface of the removable material;
removing a part of the another metal layer so as to form the concave mirror with the another metal layer on said curve; and
removing the removable material from the groove and the area above the waveguide structure and the stack structure.
2 . The method according to claim 1 , wherein the step of forming the curved mirror further comprises:
fully filling the groove with resin to form a resin layer;
patterning the resin layer according to the common focus so as to form the resin layer into a curved surface; and
forming a metal layer on the curved surface.
3 . A method for manufacturing a photonic integrated circuit structure, comprising:
providing a substrate with a surface;
forming a composite layer on the surface;
processing the composite layer to form a waveguide structure;
manufacturing the spot size converter according to the method of claim 2 ; and
disposing the spot size converter on the substrate at one side of the receiving end of the waveguide structure.
4 . The method according to claim 1 , wherein the step of forming the curved mirror further comprises:
processing the stack structure on the opposite side of the receiving end of the waveguide structure to form a curved surface opposite to the receiving end; and
forming a metal layer on the curved surface.
5 . A method for manufacturing a photonic integrated circuit structure, comprising:
providing a substrate with a surface;
forming a composite layer on the surface;
processing the composite layer to form a waveguide structure;
manufacturing the spot size converter according to the method of claim 4 ; and
disposing the spot size converter on the substrate at one side of the receiving end of the waveguide structure.
6 . The method according to claim 1 , wherein the curved mirror is a concave mirror or a convex mirror.
7 . A method for manufacturing a photonic integrated circuit structure, comprising:
providing a substrate with a surface;
forming a composite layer on the surface;
processing the composite layer to form a waveguide structure;
manufacturing the spot size converter according to the method of claim 6 ; and
disposing the spot size converter on the substrate at one side of the receiving end of the waveguide structure.
8 . The method according to claim 1 , wherein a ratio of a curvature radius of the concave mirror to a curvature radius of the curved mirror is equal to a ratio of a core radius of the transmitting end to a core radius of the receiving end.
9 . A method for manufacturing a photonic integrated circuit structure, comprising:
providing a substrate with a surface;
forming a composite layer on the surface;
processing the composite layer to form a waveguide structure;
manufacturing the spot size converter according to the method of claim 8 ; and
disposing the spot size converter on the substrate at one side of the receiving end of the waveguide structure.
10 . A method for manufacturing a photonic integrated circuit structure, comprising:
providing a substrate with a surface;
forming a composite layer on the surface;
processing the composite layer to form a waveguide structure;
manufacturing the spot size converter according to the method of claim 7 ; and
disposing the spot size converter on the substrate at one side of the receiving end of the waveguide structure.