US 12,487,409 B2
Grating coupler
Satoshi Nishikawa, Tokyo (JP); and Masahiro Matsuura, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Appl. No. 18/039,495
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
PCT Filed Dec. 14, 2020, PCT No. PCT/JP2020/046493
§ 371(c)(1), (2) Date May 31, 2023,
PCT Pub. No. WO2022/130442, PCT Pub. Date Jun. 23, 2022.
Prior Publication US 2024/0004142 A1, Jan. 4, 2024
Int. Cl. G02B 6/34 (2006.01); G02B 6/124 (2006.01)
CPC G02B 6/34 (2013.01) [G02B 6/124 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A grating coupler comprising:
a first optical waveguide chip;
a second optical waveguide chip; and
a transparent member, wherein
the first optical waveguide chip includes a first substrate including a first substrate top surface, a first optical waveguide formed on the first substrate top surface, a first waveguide grating formed on the first substrate top surface, a first chip bottom surface, a first chip top surface opposite to the first chip bottom surface, and a first chip end surface connected to the first chip top surface and the first chip bottom surface,
the first waveguide grating is connected to the first optical waveguide and is more proximal to the first chip end surface than the first optical waveguide,
the second optical waveguide chip includes a second substrate including a second substrate top surface, a second optical waveguide formed on the second substrate top surface, a second waveguide grating formed on the second substrate top surface, and a second chip top surface,
the second waveguide grating is connected to the second optical waveguide and is more proximal to the first chip end surface than the second optical waveguide,
the second waveguide grating is arranged on the first substrate side relative to the first waveguide grating in a direction in which the first chip top surface and the first chip bottom surface are spaced apart from each other,
light incident on the grating coupler passes through a first light incident/exit surface of the first optical waveguide chip and a second light incident/exit surface of the second optical waveguide chip, and is coupled between the first waveguide grating and the second waveguide grating, the first light incident/exit surface extending along the first chip end surface, the second light incident/exit surface extending along the second chip top surface,
between the first light incident/exit surface and the second light incident/exit surface, an optical path of the light within an operating wavelength range of the grating coupler is filled with the transparent member, and
the transparent member is configured to reduce a change in an incidence position of the light incident on the grating coupler within the operating wavelength range of the grating coupler, compared to a case where the transparent member is not present.