US 12,461,306 B2
Optical waveguide element, optical modulation device using optical waveguide element, and optical transmission device using optical waveguide element
Yuki Kugimoto, Tokyo (JP); Yumi Murata, Tokyo (JP); Yu Kataoka, Tokyo (JP); and Shingo Takano, Tokyo (JP)
Assigned to SUMITOMO OSAKA CEMENT CO., LTD., Tokyo (JP)
Appl. No. 18/270,168
Filed by SUMITOMO OSAKA CEMENT CO., LTD., Tokyo (JP)
PCT Filed Dec. 22, 2021, PCT No. PCT/JP2021/047528
§ 371(c)(1), (2) Date Jun. 28, 2023,
PCT Pub. No. WO2022/181021, PCT Pub. Date Sep. 1, 2022.
Claims priority of application No. 2021-031062 (JP), filed on Feb. 26, 2021.
Prior Publication US 2024/0069281 A1, Feb. 29, 2024
Int. Cl. G02B 6/122 (2006.01); G02B 6/12 (2006.01)
CPC G02B 6/1228 (2013.01) [G02B 2006/12097 (2013.01); G02B 2006/12142 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An optical waveguide element comprising:
an optical waveguide substrate having a rib-type optical waveguide made of a material having an electro-optic effect; and
spot size conversion means for changing a mode field diameter of a light wave propagating through the optical waveguide at a position where an input end or an output end of the rib-type optical waveguide is formed,
wherein the spot size conversion means includes
a first configuration layer that is connected to the rib-type optical waveguide and includes a tapered portion in which a width of the optical waveguide expands,
a second configuration layer that is laminated on the first configuration layer and has a width narrower than a width of the first configuration layer, and
a third configuration layer that is disposed to cover the second configuration layer excluding a part of the second configuration layer close to the rib-type optical waveguide and has a width wider than the width of the second configuration layer.