| CPC G02F 1/2257 (2013.01) [G02F 1/212 (2021.01)] | 17 Claims |
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1. A light modulator comprising:
a substrate including a cladding portion and a main surface having a first area, a second area, and a third area, the first area, the second area, and the third area each extending in a first direction along the main surface, the third area being disposed between the first area and the second area, and the cladding portion being located under the main surface within the substrate and under the third area;
a first III-V compound semiconductor layer of a first conductivity-type disposed on the first area and including a first portion and a second portion;
a second III-V compound semiconductor layer of the first conductivity-type or a second conductivity-type disposed on the second area;
a core disposed on the third area and containing a III-V compound semiconductor; and
an electrode connected to the first III-V compound semiconductor layer,
wherein the first portion has a thickness smaller than a thickness of the core in a second direction orthogonal to the main surface,
wherein the second portion has a thickness larger than the thickness of the first portion in the second direction, and the second portion is disposed between the first portion and the core,
wherein the cladding portion has a refractive index smaller than a refractive index of the first III-V compound semiconductor layer,
wherein the cladding portion includes a plurality of void portions and a plurality of supporting portions, each of the plurality of supporting portions supporting the core, and
wherein the plurality of void portions and the plurality of supporting portions are alternately arranged in a third direction orthogonal to both the first direction and the second direction.
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