US 12,449,574 B2
High efficiency grating coupler for a laser source
Eng Wen Ong, Breinigsville, PA (US); and Mark A. Webster, Bethlehem, PA (US)
Assigned to Cisco Technology, Inc., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on Oct. 18, 2021, as Appl. No. 17/451,265.
Prior Publication US 2023/0122662 A1, Apr. 20, 2023
Int. Cl. G02B 5/18 (2006.01); H01L 21/302 (2006.01); H01S 5/0225 (2021.01); H10H 20/819 (2025.01)
CPC G02B 5/1857 (2013.01) [H01L 21/302 (2013.01); H01S 5/0225 (2021.01); H10H 20/819 (2025.01); G02B 2005/1804 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A grating coupler having a wafer-bonded configuration, the grating coupler comprising:
a substrate;
an oxide layer disposed on the substrate;
a silicon nitride layer disposed above the oxide layer;
a polycrystalline silicon layer disposed above the silicon nitride layer;
a monocrystalline silicon layer disposed above the polycrystalline silicon layer; and
a bi-layer grating disposed above the silicon nitride layer, the bi-layer grating comprising:
a first etched layer of the polycrystalline silicon layer; and
a second etched layer of the polycrystalline silicon layer.