US 12,259,631 B2
Optical control element, optical modulation device using same, and optical transmission apparatus
Norikazu Miyazaki, Tokyo (JP); and Yu Kataoka, Tokyo (JP)
Assigned to SUMITOMO OSAKA CEMENT CO., LTD., Tokyo (JP)
Appl. No. 17/916,400
Filed by SUMITOMO OSAKA CEMENT CO., LTD., Tokyo (JP)
PCT Filed Dec. 4, 2020, PCT No. PCT/JP2020/045293
§ 371(c)(1), (2) Date Sep. 30, 2022,
PCT Pub. No. WO2021/199502, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 2020-062110 (JP), filed on Mar. 31, 2020.
Prior Publication US 2023/0152660 A1, May 18, 2023
Int. Cl. G02B 6/12 (2006.01); G02F 1/01 (2006.01); G02F 1/035 (2006.01); G02F 1/21 (2006.01); G02F 1/225 (2006.01); H04B 10/516 (2013.01)
CPC G02F 1/2255 (2013.01) [G02B 6/12 (2013.01); G02F 1/0123 (2013.01); G02F 1/035 (2013.01); G02F 1/212 (2021.01); G02F 1/225 (2013.01); H04B 10/516 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An optical control element comprising:
a substrate having an electro-optic effect;
an optical waveguide formed on the substrate; and
a control electrode controlling a light wave propagating through the optical waveguide, wherein
an input portion and an output portion of the optical waveguide are formed on the same side of the substrate,
the optical waveguide includes at least one Mach-Zehnder type optical waveguide portion that has two branched waveguides branched from one optical waveguide and combines the two branched waveguides to form one optical waveguide,
the branched waveguides have an even number of turned-back portions,
the control electrode includes a modulation electrode and a bias electrode,
the branched waveguides has a plurality of sections separated by the turned-back portions of the branched waveguides,
the modulation electrode and the bias electrode are provided in different sections of the branched waveguides,
the bias electrode is disposed in each of the sections before and after the turned-back portions,
the bias electrode has at least two wirings, each of which branches into a plurality of electrode portions,
in each of the sections, the wirings are arranged intersecting the branched waveguides,
in each of the sections, the electrode portions of the two wirings are arranged along the branched waveguides and opposite each other,
the electrode portions of one wiring and the electrode portions of the other wiring extend in opposite directions from each wiring along the branched waveguides, and
in each of the sections, the sign of the phase change formed by the bias electrode is set to be the same.