Optical waveguide structure
An optical waveguide structure includes a substrate and a core structure disposed on the substrate. The substrate includes a first waveguide region, a second waveguide region, and a transition region between the first waveguide region and the second waveguide region. The core structure includes first core segments arranged in a first direction and a second direction crossing the first direction on the transition region. The core structure includes second core segments arranged in the first direction and the second direction on the second waveguide region. The first direction and the second direction are parallel to a top surface of the substrate.
1. An optical waveguide structure comprising:
a substrate comprising a first waveguide region, a second waveguide region, and a transition region between the first waveguide region and the second waveguide region; and
a core structure disposed on the substrate,
wherein the core structure comprises:
first core segments arranged in a first direction and a second direction crossing the first direction on the transition region; and
second core segments arranged in the first direction and the second direction on the second waveguide region,
wherein the first direction and the second direction are parallel to a top surface of the substrate.
2. The optical waveguide structure of claim 1 , wherein the core structure further comprises a main core pattern crossing the first waveguide region and the transition region in the first direction, and
the main core pattern is disposed between the first core segments.
3. The optical waveguide structure of claim 2 , wherein the main core pattern crosses the second waveguide region via the transition region in the first direction, and
the main core pattern is disposed between the second core segments.
4. The optical waveguide structure of claim 3 , wherein the transition region comprises:
a first transition region adjacent to the first waveguide region; and
a second transition region adjacent to the second waveguide region,
wherein the main core pattern comprises a plurality of third core segments arranged to be spaced apart from each other in the first direction on the transition region, and
the first core segments are disposed around a column of the plurality of third core segments on the second transition region.
5. The optical waveguide structure of claim 4 , wherein each of the plurality of third core segments has a length in the first direction, and
the lengths of the plurality of third core segments gradually decrease in the first direction on the transition region.
6. The optical waveguide structure of claim 5 , wherein each of the plurality of third core segments has a width in the second direction, and
the widths of the plurality of third core segments gradually decrease in the first direction on the transition region.
7. The optical waveguide structure of claim 5 , wherein each of the plurality of third core segments has a width in the second direction, and
the widths of the plurality of third core segments gradually increase and then decrease in the first direction on the transition region.
8. The optical waveguide structure of claim 4 , wherein the main core pattern comprises a plurality of fourth core segments arranged to be spaced apart from each other in the first direction on the second waveguide region, and
the second core segments and the plurality of fourth core segments are aligned with each other in the second direction on the second waveguide region.
9. The optical waveguide structure of claim 8 , wherein the first core segments and the plurality of third core segments are aligned with each other in the second direction on the second transition region.
10. The optical waveguide structure of claim 4 , wherein the main core pattern comprises a plurality of fourth core segments arranged to be spaced apart from each other in the first direction on the second waveguide region, and
the second core segments and the plurality of fourth core segments are arranged in a zigzag form in the second direction on the second waveguide region.
11. The optical waveguide structure of claim 10 , wherein the first core segments and the plurality of third core segments are arranged in a zigzag form in the second direction on the second transition region.
12. The optical waveguide structure of claim 3 , wherein the transition region comprises:
a first transition region adjacent to the first waveguide region; and
a second transition region adjacent to the second waveguide region,
wherein the main core pattern has a line shape that is tapered in the first direction on the transition region, and
the first core segments are disposed around the main core pattern on the second transition region.
13. The optical waveguide structure of claim 12 , wherein the main core pattern has a line shape extending in the first direction on the second waveguide region, and
the second core segments are aligned with each other in the second direction with the main core pattern therebetween on the second waveguide region.
14. The optical waveguide structure of claim 13 , wherein the first core segments are aligned with each other in the second direction with the main core pattern therebetween on the second transition region.