US 11,693,186 B2
Two-dimensional grating coupler and methods of making same
Chih-Tsung Shih, Hsinchu (TW); Chewn-Pu Jou, Hsinchu (TW); Stefan Rusu, Sunnyvale, CA (US); Felix Ying-Kit Tsui, Cupertino, CA (US); and Lan-Chou Cho, Hsinchu (TW)
Assigned to Taiwan Semiconductor Manufacturing Co., Ltd., Hsin-Chu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsin-Chu (TW)
Filed on Apr. 1, 2021, as Appl. No. 17/220,724.
Prior Publication US 2022/0317379 A1, Oct. 6, 2022
Int. Cl. G02B 6/34 (2006.01); G02B 6/30 (2006.01)
CPC G02B 6/34 (2013.01) [G02B 6/305 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus for optical coupling, comprising:
a planar layer;
a grating region comprising an array of scattering elements arranged in the planar layer to form a two-dimensional (2D) grating;
a first taper structure formed in the planar layer connecting a first side of the grating region to a first waveguide, wherein a shape of the first taper structure is a first triangle that is asymmetric about any line perpendicular to the first side of the grating region in the planar layer; and
a second taper structure formed in the planar layer connecting a second side of the grating region to a second waveguide, wherein a shape of the second taper structure is a second triangle that is asymmetric about any line perpendicular to the second side of the grating region in the planar layer, wherein the first side and the second side are substantially perpendicular to each other, wherein:
the array of scattering elements are evenly distributed in the planar layer such that there is a same distance between centers of every two adjacent scattering elements along either a first direction perpendicular to the first side of the grating region or a second direction perpendicular to the second side of the grating region,
the first triangle has a first base side residing on the first side of the grating region, has a first vertex opposite to the first base side, and has a first length along the first direction,
the first vertex has a first distance to a perpendicular bisector of the first base side in the planar layer,
the second triangle has a second base side residing on the second side of the grating region, has a second vertex opposite to the second base side, and has a second length along the second direction,
the second vertex has a second distance to a perpendicular bisector of the second base side in the planar layer; and
the first distance and the second distance are equal to each other.