US 12,436,442 B2
Waveguide device, optical scanning device and optical modulation device
Kentaro Tani, Miyoshi (JP); Jungo Kondo, Nagoya (JP); Keiichiro Asai, Nagoya (JP); Shuhei Higashihara, Nagoya (JP); and Naoki Fujita, Nagoya (JP)
Assigned to NGK INSULATORS, LTD., Nagoya (JP)
Filed by NGK INSULATORS, LTD., Nagoya (JP)
Filed on Jan. 12, 2024, as Appl. No. 18/411,196.
Application 18/411,196 is a continuation of application No. PCT/JP2022/018041, filed on Apr. 18, 2022.
Claims priority of application No. 2021-116666 (JP), filed on Jul. 14, 2021.
Prior Publication US 2024/0142852 A1, May 2, 2024
Int. Cl. G02F 1/313 (2006.01)
CPC G02F 1/313 (2013.01) 8 Claims
OG exemplary drawing
 
1. An optical scanning device, comprising:
a photonic crystal layer having holes periodically formed in an electro-optical crystal substrate;
a line-defect optical waveguide formed in the photonic crystal layer;
a first electrode arranged above the electro-optical crystal substrate, the first electrode being transparent to light;
a second electrode arranged below the electro-optical crystal substrate, and
a diffraction grating arranged in at least one portion selected from an upper portion, a left side surface portion, and a right side surface portion of the optical waveguide,
wherein each of the first electrode and the second electrode overlaps the optical waveguide in a thickness direction of the photonic crystal layer,
wherein a refractive index of the first electrode is lower than a refractive index of the electro-optical crystal substrate,
wherein a refractive index difference between the electro-optical crystal substrate and the first electrode is 0.2 or more and 1.2 or less,
wherein the first electrode is configured to change an emission angle of light emitted from an upper surface of the optical waveguide and to transmit the emitted light.