US 12,130,536 B2
Optical modulator
Norikazu Miyazaki, Tokyo (JP); Kosuke Okahashi, Tokyo (JP); and Masayuki Motoya, Tokyo (JP)
Assigned to SUMITOMO OSAKA CEMENT CO., LTD., Tokyo (JP)
Appl. No. 17/599,491
Filed by SUMITOMO OSAKA CEMENT CO., LTD., Tokyo (JP)
PCT Filed Aug. 15, 2019, PCT No. PCT/JP2019/032007
§ 371(c)(1), (2) Date Sep. 28, 2021,
PCT Pub. No. WO2020/202596, PCT Pub. Date Oct. 8, 2020.
Claims priority of application No. 2019-067717 (JP), filed on Mar. 29, 2019.
Prior Publication US 2022/0146901 A1, May 12, 2022
Int. Cl. G02F 1/21 (2006.01); G02F 1/225 (2006.01)
CPC G02F 1/212 (2021.01) [G02F 1/2255 (2013.01)] 4 Claims
OG exemplary drawing
 
1. An optical modulator comprising:
a substrate having an electro-optic effect; and
an optical waveguide and a control electrode that are formed on the substrate, wherein
the optical waveguide has a structure in which a plurality of Mach-Zehnder type optical waveguides are disposed in parallel,
the control electrode has a GSSG type differential electrode structure in which two signal electrodes S are disposed between two ground electrodes G for one of the Mach-Zehnder type optical waveguides,
a distance W1 between the two signal electrodes S is set to less than twice a distance W2 between the adjacent signal electrode S and the ground electrode G,
a crosstalk suppressing unit that suppresses signal crosstalk is provided in the ground electrode sandwiched between adjacent Mach-Zehnder type optical waveguides,
the crosstalk suppressing unit is a protrusion formed on an upper surface of the ground electrode corresponding to, or aligned with, a resin layer, the resin layer arranged between the ground electrode and the substrate, and
the protrusion is higher than the upper surface of the signal electrode.