Sumitomo Electric Industries, Limited

Hajime Tanaka

Tsutomu Ishikawa

Masataka Watanabe

Naoya Kono

Naoki Fujiwara

The light modulator includes a substrate having a main surface including a first area, a second area, and a third area, a first III-V compound semiconductor layer of a first conductivity-type provided on the first area, a second III-V compound semiconductor layer of a first conductivity-type or a second conductivity-type provided on the second area, a core provided on the third area and including a group III-V compound semiconductor, and an electrode connected to the first III-V compound semiconductor layer. The first III-V compound semiconductor layer includes a first portion having a thickness smaller than a thickness of the core in a second direction orthogonal to the main surface and a second portion having a thickness larger than the thickness of the first portion in the second direction. The second portion is disposed between the first portion and the core.

Light modulator

An optical modulator includes a waveguide formed of a semiconductor and configured to allow light to propagate therethrough; a first electrode disposed on the waveguide and electrically connected to the waveguide; and a second electrode separated from the waveguide and electrically connected to the waveguide. An edge of the second electrode on a light entry side is located downstream of an edge of the first electrode on the light entry side in a propagation direction of the light.

Optical modulator

A spot size converter includes a first waveguide including a first core layer, the first waveguide propagating light; and a second waveguide including a second core layer and provided on the first waveguide, the second waveguide propagating light. The first waveguide and the second waveguide extend in a waveguide direction. A first region and a second region are provided continuously along the waveguide direction. In the first region, the second waveguide has a tapered shape in a cross section which becomes narrower as going up away from the first waveguide. An angle between a side surface of the second waveguide and a bottom surface of the second waveguide is 60&#xb0; or less.

Spot size converter and manufacturing method of the same

An optical modulator includes: a waveguide made of semiconductor, a light being input to one of ends of the waveguide; and a first electrode provided on the waveguide and overlapping with a part of the waveguide, wherein the waveguide has a first region to a third region along a propagation direction of the light from the one of ends, wherein neither the first region nor a part of the second region on a side of the first region in the propagation direction overlaps with the first electrode, wherein the third region and a part of the second region on a side of the third region in the propagation direction overlap with the first electrode, wherein a second width of the second region is larger than a first width of the first region and a third width of the third region.

A multimode interferometer includes: a multimode waveguide mesa having a top face extending in a direction of a first axis, a first side face and a second side face that extend in the direction of the first axis, and a first end face and a second end face that are arranged in the direction of the first axis; and a waveguide mesa connected to the first end face at a port; first and second waveguide mesas connected to first and second ports on the second end face. The multimode waveguide mesa has a first side edge line shared by the top face and the first side face, and an end line shared by the top face and the first end face. The first side edge line forms an acute angle with the end line at an outer vertex where the first side edge line and the end line meet.

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Osaka, Japan

Hajime Tanaka